Journal of Science and Medicine in Sport

Journal of Science and Medicine in Sport

Attitudes, beliefs and knowledge related to doping in football players

01-08-2019 – Gordon S. Waddington

Editorial

The influence of bowling velocity on movement variability in experienced older aged lawn bowlers

06-05-2019 – Mark G.L. Sayers

Journal Article

Objectives

This project examined the movement strategies adopted by highly experienced older aged lawn bowlers when performing Draw and Drive deliveries.

Design

Cross-sectional.

Methods

Twenty five experienced (10.2 ± 7.8 years) older aged lawn bowlers (67.3 ± 7.0 years) who play lawn bowls at least once per week volunteered to participate in this study. Participants performed 10 Draw and Drive deliveries at a target positioned 23 m away while standing on two force platforms (600 Hz), while an infrared motion capture system (200 Hz) recorded phases times and both foot and bowl positioning. Normalised root mean square (No
RMS) analyses was used to assess the bowl path consistency during the delivery phase. Correlation analyses assessed for relationships between age and experience and the spatiotemporal variables, with paired t-tests and effect size (ES) analyses used to examine differences between delivery types.

Results

None of the spatiotemporal or No
RMS data achieved more than low correlations with either age or playing experience (R2 < 0.2). Although bowl release velocities were significantly slower for the Draw 5.25 ± 0.72 m/s than for the Drive deliveries 6.40 ± 0.97 m/s (p < 0.001, ES = 1.96) there were limited changes in any of the spatiotemporal variables. No
RMS data remained largely unchanged between Draw (5.10 ± 1.65) and Drive (5.07 ± 1.49, p = 0.925, ES = 0.02) deliveries.

Conclusions

These highly experienced lawn bowlers are adapting their technique to the different task demands of the two delivery types without altering their specific movement strategies.

Using 360° virtual reality as a decision-making assessment tool in sport

17-04-2019 – Aden Kittel, Paul Larkin, Nathan Elsworthy, Michael Spittle

Journal Article

Objectives

To examine the reliability, construct validity and ecological validity of 360° VR and match broadcast footage for off-field decision-making assessment in Australian football umpires.

Design

Validation assessments with test re-test reliability.

Methods

Two video-based tests of 60 clips each were developed to assess Australian football umpire decision-making, including 360° video of small-sided Australian football games and match broadcast footage of AFL games. Elite (n = 13) and amateur (n = 15) umpires participated in two testing sessions, in a randomised, counterbalanced design. Test re-test reliability was assessed using Cohen’s Kappa for individual clips and Intraclass Correlation Coefficients for test scores. Video tests were assessed for construct validity. Ecological validity of the decision-making processes was assessed for each method.

Results

31 clips met the minimum Kappa criteria for the 360° VR test and 28 clips for match broadcast. Results indicated strong reliability for the 360° VR (ICC = 0.89) and match broadcast (ICC = 0.89) tests. For both video modes, elite umpires performed significantly better in decision-making accuracy than amateur (p < 0.05). For ecological validity of the decision-making processes, 360° VR was rated significantly higher than match broadcast vision (p < 0.05) overall.

Conclusions

This is the first study to examine the reliability and validity of 360° VR footage as an off-field decision-making assessment tool in sport. As match broadcast vision is commonly used to assess decision-making in athletes and officials, results suggest that 360° VR is also an appropriate assessment tool. Although both video modes demonstrate similar reliability and construct validity, 360° VR was considered more specific to in-game decision-making processes, suggesting stronger ecological validity.

Changes in inflammation markers after a 10-week high-intensity combined strength and endurance training block in women: The effect of hormonal contraceptive use

13-06-2019 – J.K. Ihalainen, A.C. Hackney, R.S. Taipale

Journal Article

Objectives

The influence of hormonal contraceptives (HC) on inflammation and body composition after high-intensity combined strength and endurance training was investigated.

Design

Active healthy women formed two training groups: HC users (HCU, n = 9) and those who had never used HC (NHC, n = 9). Training included two strength training sessions and two high-intensity interval training sessions per week for 10 weeks.

Methods

Before (PRE) and after (POST) the training intervention, high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1beta (IL-1β) concentrations were measured. Dual-energy X-ray absorptiometry was used to estimate fat mass (FM), abdominal fat mass (a
FM), and lean mass (LM).

Results

Circulating concentrations of hs-CRP decreased significantly in the NHC from pre to post with −0.46 mg l−1 (95% CI: −0.78, −0.14, p = 0.009, ES = 0.434), whereas a significant increase was observed in HCU from pre to post with 0.89 mg l−1 (95% CI: 1.66, 0.12, p = 0.048, ES = 1.988) with a significant between-group difference (p = 0.015). In addition, hs-CRP concentration was significantly higher in HCU than in NHC after training (p = 0.036) at post. Lean mass increased significantly more in NHC than in HCU (p = 0.049).

Conclusions

High-intensity combined strength and endurance training can modify inflammation and body composition of women. The present study showed that inflammation, in terms of hs-CRP was higher post training in HCU than NHC, which may be associated with smaller gains in lean mass in response to training.

Normative values of the motor competence assessment (MCA) from 3 to 23 years of age

04-06-2019 – Luis P. Rodrigues, Carlos Luz, Rita Cordovil, Pedro Bezerra, Bruno Silva, Miguel Camões, Ricardo Lima

Journal Article

Objectives

Growing evidence of the importance of motor competence for developing a healthy lifestyle has been established in the last decade. Nonetheless, no single instrument or observation tool have been able to fully measure this construct, particularly because most were built for the diagnosis of children in risk for motor impairment; are limited to a few years of the developmental span; lack objectivity in the assessment protocols; or do not include the locomotor, stability, and manipulative components. This led to the difficulty of comparing researches, and longitudinally follow children into adulthood. Recently, a novel proposal to assess motor competence was presented – the Motor Competence Assessment (MCA) – and this study aims to present the MCA normative data from 3-to-23 years.

Design and methods

Two thousand and eighty-seven participants (1102 boys) between 3 and 23 years of age were evaluated in the MCA (standing long jump, 10 m shuttle run, throwing velocity, kicking velocity, lateral jumps, shifting platforms). Results for each test were introduced in the LMS Chartmaker 2.3. The best model for test and sex was used, resulting in normative curves and percentile values.

Results

Final norms showed a good fit to the instrument developmental expectations, allowing to differentiate and classify performances along the age interval.

Conclusions

The MCA age- and sex- normative values allow to assess motor competence from childhood to early adulthood. Future directions will include obtaining a total MCA score and the normative scores for the MCA components (stability, locomotion, object control), and to expand the norms to adulthood and old age.

Normative Yo-Yo Intermittent Recovery Level 1 and Yo-Yo Intermittent Endurance Level 1 test values of boys aged 9–16 years

17-06-2019 – Boris Schmitz, Carina Pfeifer, Kiana Kreitz, Matthias Borowski, Andreas Faldum, Stefan-Martin Brand

Journal Article, Review

Objectives

To provide age- and sex-specific reference values of Yo-Yo tests in children and adolescents.

Design

Systematic review.

Methods

A literature search for articles on Yo-Yo Intermittent (YYI) tests was performed in MEDLINE, SPORTDiscus, Web of Science and Google Scholar. Original reports on healthy children/adolescents 6–16 years of age were eligible. For each test, age- and sex-related reference values were calculated using global means and percentiles.

Results

Ninety-two studies (7398 participants) fulfilled the eligibility criteria. The YYI tests most frequently used were the Yo-Yo Intermittent Recovery Level 1 test (YYIR1, 57.8%), Yo-Yo Intermittent Endurance Level 1 test (YYIE1, 14.7%), Yo-Yo Intermittent Recovery Level 1 Children’s test (YYIR1C, 12.7%), Yo-Yo Intermittent Endurance Level 2 test (YYIE2, 8.8%) and the Yo-Yo Intermittent Recovery Level 2 test (YYIR2, 5.9%). Of these, 71.6% reported test results of boys, 17.6% reported mixed test results and 10.8% reported test results of girls. Smoothed centile curves for the YYIR1 and YYIE1 over the entire age range were generated for boys, revealing constantly increasing performance with increasing age.

Conclusions

YYI tests values differ with respect to age and sex. In boys, development of YYIR1 and YYIE1 test values (6–16 years of age) was different, suggesting better applicability of the YYIR1 test for boys >13 years of age. The results may be used to rate YYI test performance for continuous screening and to identify children with low physical fitness. Since limited data was available of females, further research on YYI tests is needed with respect to sex-specific results.

The use of the Körperkoordinationstest für Kinder in the talent pathway in youth athletes: A systematic review

22-06-2019 – J. O’Brien-Smith, R. Tribolet, M.R. Smith, K.J.M. Bennett, J. Fransen, J. Pion, M. Lenoir

Journal Article, Review

Objectives

Identifying talented athletes from an early age to accelerate their development requires the investment of substantial resources. Due to the need for multifactorial approaches to talent identification, motor competence assessments are increasingly prevalent in contemporary testing batteries. Therefore, the aim of this review was to evaluate the literature on the use of a product-oriented motor competence assessment tool, the Körperkoordinationstest für Kinder (KTK) in the talent pathway and determine whether it is warranted in such programs.

Methods

Three electronic databases (i.e. PubMed, SPORTDiscus and Web of Science) were searched for studies that used at least one component of the KTK to assess motor competence for talent detection, identification, development and selection in athletic populations. A total of 21 articles were included in the review, of which seven used the full version of the KTK and 14 used modified versions or individual components of the battery. The quality of included studies was assessed using a modified version of the Joanna Brigg’s Institute Critical Appraisal Checklist.

Results

The analysed literature suggests that the KTK can successfully distinguish between athletes of different competition levels and across different sporting domains, however, findings should be interpreted with caution due to the cross-sectional nature of the studies. Furthermore, the moving sideways subtest displayed the greatest discriminative power for athletes of different competition levels. Motor competence was not affected by maturation and did not differ between genders or playing positions.

Conclusions

Collectively, these findings suggest that the KTK is a useful motor competence assessment in the talent pathway.

The incidence, prevalence, nature, severity and mechanisms of injury in elite female cricketers: A prospective cohort study

12-06-2019 – Nirmala Kanthi Panagodage Perera, Alex Kountouris, Joanne L. Kemp, Corey Joseph, Caroline F. Finch

Journal Article

Objectives

Incidence, prevalence, nature, severity and mechanisms of injury in elite female cricketers over two seasons from March 2014 to March 2016, inclusive.

Design

Prospective cohort study.

Methods

Injury data collected via Cricket Australia’s Athlete Management System on all elite female players over two seasons were analysed. Profiles of the nature, anatomical location and mechanism of injuries were presented according to dominant player position. Injury incidence rates were calculated based on match playing hours.

Results

There were 600 medical-attention injuries; with 77.7% players reporting ≥1 injury. There were 79.5% acute injuries compared to gradual onset injuries. Of the all medical-attention injuries, 20.2% led to time-loss; 34.7% were match-time-loss injuries. Match injury incidence was 424.7 injuries/10,000 h for all injuries and 79.3 injuries/10,000 h for time-loss injuries. Of all the injuries, 31.8% were muscle injuries and 16.0% joint sprains. Wrist and hand (19.8%), lumbar spine (16.5%) and knee (14.9%) injuries were the most common time-loss injuries. Six players sustained lumber spine bone stress injury that resulted in the most days missed due to injury (average 110.5 days/injury).

Conclusions

There is a need to focus on specific injuries in female cricket, including thigh, wrist/hand and knee injuries because of their frequency, and lumbar spine injuries because of their severity.

Do riders who wear an air jacket in equestrian eventing have reduced injury risk in falls? A retrospective data analysis

05-06-2019 – Lindsay E. Nylund, Peter J. Sinclair, Peta L. Hitchens, Stephen Cobley

Journal Article

Objectives

To investigate the association between air jacket usage and rider injury severity in equestrian eventing competition falls world-wide.

Design

Retrospective data analysis.

Methods

An analysis was conducted on Fédération Equestre Internationale data for 1819 riders who fell wearing an air jacket and 1486 riders who fell while not wearing an air jacket from 2015 to 2017. Injury data were categorised as either ‘no/slight injury’ or ‘serious/fatal injury’. A chi-square test determined whether an association was present between injury severity category and air jacket usage and binary logistic regression determined the effect size of this association.

Results

As a result of falls, 3203 riders sustained no/slight injuries and 102 sustained serious/fatal injuries. While 55.0% of riders who fell were wearing an air jacket, they represented 67.6% of the serious/fatal injury outcomes. Air jacket usage was significantly associated with serious/fatal injuries in falls ( = 6.76; p = 0.009). Riders wearing an air jacket had 1.7 times (95%CI 1.14–2.64) increased odds of sustaining a serious or fatal injury in a fall compared to riders not wearing an air jacket.

Conclusions

Riders wearing an air jacket were over represented in the percentage of serious or fatal injuries in falls compared to riders who only wore a standard body protector. Further research is needed to understand the reason(s) for this finding. It is recommended that additional data on injury outcomes, rider characteristics and the biomechanics of falls be examined in future analyses, and that air jacket and body protector characteristics be further investigated.

Variation in renal responses to exercise in the heat with progressive acclimatisation

16-05-2019 – Jessica Omassoli, Neil E. Hill, David R. Woods, Simon K. Delves, Joanne L Fallowfield, Stephen J. Brett, Duncan Wilson, Richard W. Corbett, Adrian J. Allsopp, Michael J. Stacey

Journal Article

Objectives

To investigate changes in renal status from exercise in the heat with acclimatisation and to evaluate surrogates markers of Acute Kidney Injury.

Design

Prospective observational cohort study.

Methods

20 male volunteers performed 60 min standardised exercise in the heat, at baseline and on four subsequent occasions during a 23-day acclimatisation regimen. Blood was sampled before and after exercise for serum creatinine, copeptin, interleukin-6, normetanephrine and cortisol. Fractional excretion of sodium was calculated for corresponding urine samples. Ratings of Perceived Exertion were reported every 5 min during exercise. Acute Kidney Injury was defined as serum creatinine rise ≥26.5 μmol L−1 or fall in estimated glomerular filtration rate >25%. Predictive values of each candidate marker for developing Acute Kidney Injury were determined by ROC analysis.

Results

From baseline to Day 23, serum creatinine did not vary at rest, but showed a significant (P < 0.05) reduction post-exercise (120 102, 139 versus 102 91, 112 μmol L−1). Acute Kidney Injury was common (26/100 exposures) and occurred most frequently in the unacclimatised state. Log-normalised fractional excretion of sodium showed a significant interaction (exercise by acclimatization day), with post-exercise values tending to rise with acclimatisation. Ratings of Perceived Exertion predicted AKI (AUC 0.76, 95% confidence interval 0.65–0.88), performing at least as well as biochemical markers.

Conclusions

Heat acclimatization is associated with reduced markers of renal stress and AKI incidence, perhaps due to improved regional perfusion. Acclimatisation and monitoring Ratings of Perceived Exertion are practical, non-invasive measures that could help to reduce renal injury from exercise in the heat.

Using causal energy categories to report the distribution of injuries in an active population: An approach used by the U.S. Army

30-04-2019 – Veronique D. Hauschild, Anna Schuh-Renner, Terrence Lee, Melissa D. Richardson, Keith Hauret, Bruce H. Jones

Journal Article

Objectives

To describe the etiologic distribution of all injuries among U.
S. Army Active Duty soldiers by causal energy categories.

Design

Retrospective cohort, descriptive analysis.

Methods

Injury was defined as the interruption of tissue function caused by an external energy transfer (mechanical, thermal, radiant, nuclear, chemical, or electrical energy). A comprehensive injury matrix standardized categories by causal energies, body locations, and injury types. Categories differentiated acute (ACT) from cumulative micro-traumatic (CMT) overuse injuries, and musculoskeletal injuries (MSKI) from those affecting other or multiple body systems (non-MSKI). International Classification of Diseases (ICD) diagnoses codes were organized into established categories. The matrix was applied to electronic health records for U.
S. Army soldiers in 2017.

Results

Mechanical energy transfers caused most injuries (97%, n = 809,914): 76% were CMT overuse and the remaining were ACT (<21%). The majority (83%) were MSKI (71% CMT, 12% ACT). While almost one-half (47%) were to lower extremities (38% CMT, 9% ACT) the most frequently injured anatomical sites were the knee and lower back (16% each, primarily CMT).

Conclusions

For the first time all soldiers’ injuries have been presented in the same context for consistent comparisons. Findings confirm the vast majority of injuries in this physically-active population are MSKI, and most are CMT MSKI. A very small portion are non-MSKI or injuries caused by non-mechanical energy (e.g., heat- or cold-weather). Most Army injuries are to the lower extremities as a grouped body region, but additional matrix specificity indicates the most injured anatomical locations are the knee, lower back, and shoulder.

MRI findings are associated with time to return to play in first class cricket fast bowlers with side strain in Australia and England

27-06-2019 – Andrew R. Nealon, Sean I. Docking, Phil E. Lucas, David A. Connell, Eamon S. Koh, Jill L. Cook

Journal Article

Objectives

To investigate the reliability of reporting and relationship between MRI parameters at injury and time to return to play (RTP) in first class cricket fast bowlers with side strain in Australia and England.

Design

Cohort study.

Methods

Eighty MRI scans of side strain injuries to 57 fast bowlers were sourced. Ten scans were reported by three experienced radiologists to determine intra- and inter-rater reliability. The relationship between six MRI parameters (muscle injured, presence of a muscle tear, rib level of injury, presence of blood fluid products/haematoma, periosteal stripping, rib oedema) and time to RTP was investigated with 39 scans reported by a single radiologist with known intra-rater reliability. The association between parameters and time to RTP was analysed with an ordinal logistic regression model.

Results

Recovery time was prolonged with a mean of 39 days (standard deviation: 14 days) and 44% of bowlers requiring more than 6 weeks to RTP. Reliability levels between parameters varied widely. The presence or absence of a muscle tear was the only MRI parameter associated with time to RTP. Players with a muscle tear were 8 times more likely to take more than 6 weeks to RTP. The multifactorial model was predictive of recovery time in only 53% of this cohort, leaving 47% of total variance in time to RTP unexplained.

Conclusions

The presence of a muscle tear was associated with time to RTP in cricket fast bowlers with side strain injury in first class cricket in Australia and England.

Mechanisms of traumatic injury to the shoulder girdle in the Australian Football League

17-06-2019 – Laura M. Schwab, Tim McGrath, Melinda M. Franettovich Smith, M. Dilani Mendis, Deirdre McGhee, Julie Hides

Journal Article

Objective

To investigate mechanisms of shoulder girdle injuries and their impact on players from the Australian Football League (AFL).

Design

Retrospective video analysis.

Methods

Two experienced sports physiotherapists (>10 years) examined video footage of shoulder complex injuries that occurred in the 2015 premiership season. Information obtained from video footage included activity prior to injury; mechanism of injury; arm, head and neck position and point of body contact at the time of injury. Player demographics and injury characteristics were obtained from club and media data.

Results

The most common mechanism of injury was lateral contact (34.6%) followed by hyperflexion/ abduction of the shoulder (19.2%). Glenohumeral joint (GHJ) dislocations and subluxations were the most frequent diagnosis for all mechanisms of injury, and occurred in a variety of shoulder positions. Over 80% of injuries occurred with the arm below 100° of shoulder flexion or abduction. The most common activity prior to injury was ‘ball in dispute’ (34.6%). Lateral contact injuries had the highest overall severity (two-thirds of players missed >3 games) and over 50% of shoulder injuries required surgery. Players missed on average 5.1 season games due to shoulder injury.

Conclusion

The lateral contact mechanism was the most common and severe mechanism of shoulder injury. Improved understanding of shoulder girdle injury mechanisms can help guide the use of preventative strategies and injury management programs in elite AFL players.

Attitudes, beliefs and knowledge related to doping in different categories of football players

28-05-2019 – Jaime Morente-Sánchez, Thomas Zandonai, Mikel Zabala Díaz

Journal Article

Objectives

The aim of this study was to study and compare attitudes, beliefs and knowledge about doping of footballers, from elite to under-18 categories.

Design

The descriptive exploratory design used an instrument combining a validated questionnaire (Performance Enhancement Attitude Scale: PEAS) with qualitative open-ended questions.

Methods

A total of 1324 Spanish football players (average age 22.56 ± 5.62 years) from 88 football teams that ranged from elite to under-18 categories: Elite (ELI, n = 304), non-elite Professional (PRO, n = 308), top Amateur (AMA, n = 330), elite Under-18 (U18, n = 334) and elite Female (FEM, n = 48) composed the sample.

Results

PEAS overall scores (range 17–102, with higher scores representing more permissive attitudes) was 34.02 ± 11.08. The overall scores for all groups analysed were: FEM: 33.75 ± 14.73; ELI: 30.61 ± 9.91; PRO: 34.23 ± 11.13; AMA: 35.05 ± 10.35; and U18: 35.93 ± 11.50. Significant differences were observed between ELI and PRO (p < 0.001), ELI and AMA (p < 0.001), and ELI and U18 (p < 0.001). 95% of participants did not know the meaning of WADA; 97.4% did not know the Prohibited List; 5% admitted having used banned substances and 23.7% knew dopers.

Conclusions

This study showed different an important lack of knowledge about doping and an high levels of supplement use in this sample of footballers assessed. It which clearly reinforces the idea of implementing a wide educational doping prevention programme in football environment.

Decreased dynamic balance and dorsiflexion range of motion in young and middle-aged adults with chronic ankle instability

28-05-2019 – Kyle B. Kosik, Nathan F. Johnson, Masafumi Terada, Abbey C. Thomas, Carl G. Mattacola, Phillip A. Gribble

Journal Article

Objectives

The purpose of this study was to compare dynamic balance and weight-bearing dorsiflexion range of motion between young and middle-aged adults with and without chronic ankle instability.

Design

Cross-sectional.

Methods

One hundred and two young adults were classified as either having chronic ankle instability (n = 38), coper (n = 27) or a healthy-control (n = 37). A total of 55 middle-aged adults were identified as having chronic ankle instability (n = 16), coper (n = 15) or a healthy-control (n = 24). Participants completed the weight-bearing lunge test and the anterior, posteromedial and posterolateral reach directions of the star excursion balance test.

Results

Middle-aged adults had shorter reach distances for each direction of the star excursion balance test compared to the young adults (p < 0.001). Regardless of age, participants with chronic ankle instability performed worse on the star excursion balance test compared to the coper (p < 0.05) and healthy-control group (p < 0.05). Similarly, participants with chronic ankle instability had less dorsiflexion compared to healthy-controls (p < 0.05), but not the coper group (p > 0.05).

Conclusions

Deficits in dynamic postural control do not continue to decline with advancing age in individuals with chronic ankle instability, however, these impairments appear to continue to persist compared to uninjured controls.

Comment on: “CrossFit and rhabdomyolysis: A case series of 11 patients presenting at a single academic institution”

28-05-2019 – Fábio Hech Dominski, Thaís Cristina Siqueira, Thiago Teixeira Serafim, Alexandro Andrade

Letter

Energetically optimal stride frequency is maintained with fatigue in trained ultramarathon runners

29-04-2019 – Gianluca Vernillo, Gregory Doucende, Johan Cassirame, Laurent Mourot

Journal Article

Objectives

At a given running speed, humans naturally endeavor to achieve an optimal stride frequency that minimizes metabolic cost. Research has suggested that runners select this near optimal stride frequency in some process of self-optimization even during fatiguing tasks up to 1-h of high-intensity running. Here, we studied whether runners demonstrate a similar self-optimizing capability after an ultramarathon of 6 h.

Design

Controlled pre-post study.

Method

We collected temporal stride kinematics and metabolic data in nine (experimental group) male runners before and after 6 h of running and in six (control group) male ultramarathon runners who did not run, but stayed awake and performed normal, daily physical activities avoiding strenuous exercises over the 6-h period. For each participant, preferred and optimal stride frequencies were measured, where stride frequency was systematically varied above and below PSF (±4% and ±8%).

Results

Preferred and optimal stride frequencies across time and group showed no significant differences (p ≥ 0.276). Furthermore, neither the overall relationship between metabolic cost and stride frequency, nor the energetically optimal stride frequency changed substantially after several hours of running.

Conclusions

Similar dynamics of stride frequency adjustments in the experimental group occurred as those found in a non-fatigued state. This suggests that after an ultramarathon of 6 h, runners were still able to optimize their gait, and automatically adjust it in order to converge on the energetically optimal gait.

Four men in a boat: Ultra-endurance exercise alters the gut microbiome

06-05-2019 – David M. Keohane, Trevor Woods, Pat O’Connor, Sean Underwood, Owen Cronin, Ronan Whiston, Orla OSullivan, Paul Cotter, Fergus Shanahan, Michael G.M Molloy

Journal Article

Objectives

Compositional and functional adaptions occur in the gut microbiome in response to habitual physical activity. The response of the gut microbiome to sustained, intense exercise in previously active individuals, however, is unknown. This study aimed to prospectively explore the gut microbiome response of four well-trained male athletes to prolonged, high intensity trans-oceanic rowing, describing changes in microbial diversity, abundance and metabolic capacity.

Design

A prospective, repeated-measures, within-subject report.

Methods

Serial stool samples were obtained from four male athletes for metagenomic whole-genome shotgun sequencing to record microbial community structure and relevant functional gene profiles before, during and after a continuous, unsupported 33-day, 5000 km transoceanic rowing race. Calorific intake and macronutrient composition were recorded by validated food frequency questionnaire and anthropometry was determined by body composition analysis and cardiorespiratory testing.

Results

Microbial diversity increased throughout the ultra-endurance event. Variations in taxonomic composition included increased abundance of butyrate producing species and species associated with improved metabolic health, including improved insulin sensitivity. The functional potential of bacterial species involved in specific amino and fatty acid biosynthesis also increased. Many of the adaptions in microbial community structure and metaproteomics persisted at three months follow up.

Conclusions

These findings demonstrate that prolonged, intense exercise positively influences gut microbial diversity, increases the relative abundance of some bacterial species and up-regulates the metabolic potential of specific pathways expressing microbial gene products. These adaptions may play a compensatory role in controlling the physiological stress associated with sustained exertion as well as negating the deleterious consequences accompanying endurance exercise.

Australian netball injuries in 2016: An overview of insurance data

17-08-2019 – Corey Joseph, Geraldine Naughton, Alanna Antcliff

Journal Article

Objectives

The objective of this study is to profile the netball-specific sporting injuries from in a national community-level insurance claim database.

Design

An audit of insurance injury claims.

Methods

An electronic dataset containing successful injury insurance claim data from the 2016 netball season was retrospectively coded. Data were de-identified and coded to meet the Orchard Sports Injury Classification System. Descriptive data reported included age, injury date, activity type, anatomical injury location, nature of injury, weather conditions, indoor/outdoor surface, quarter injury occurred, and open text for injury description.

Results

The dataset contained 1239 claims that were approved for payment by the insurance company. The overall incidence rate was 2.936 successful injury claims per 1000 participants. The average age of players with claims was 34 years. The majority of successful claims came from players aged 22 to 29 years (n = 328; 27%) and 30–39 years (n = 279; 23%) age groups. Of the successful claims for injury, most occurred during matches (n = 1116; 92%), and were for injuries to the knee (n = 509; 42%) and ankle (n = 356; 29%) and for sprains/ligament damage (n = 687; 57%) or fractures (n = 182; 15%).

Conclusions

Netball injuries profiled by an injury insurance dataset of successful claims mostly occurred to the knee and ankle. Sprains and ligament damage were the most common type of injury. This study strengthens the evidence for national injury prevention policies and strategies. Findings from the current study could be used in future to expand into mechanisms of injury, and injury diagnoses.

Validity and reliability assessment of 3-D camera-based capture barbell velocity tracking device

20-08-2019 – Curtis L. Tomasevicz, Ryan M. Hasenkamp, Daniel T. Ridenour, Christopher W. Bach

Journal Article

Velocity-based training (VBT) requires the monitoring of lift velocity plus the prescribed resistance weight. A validated and reliable device is needed to capture the velocity and power of several exercises.

Objectives

The study objectives were to examine the validity and reliability of the Elite Form Training System® (EFTS) for measures of peak velocity (PV), average velocity (AV), peak power (PP), and average power (AP).

Design

Validity of the EFTS was assessed by comparing measurements simultaneously obtained via the Qualisys Track Manager software (C-motion, version 3.90.21, Gothenburg, Sweden) utilizing 6 motion capture cameras (Oqus 400, 240 Hz, Gothenburg, Sweden).

Methods

Six participants performed 6 resistance exercises in 2 sessions: power clean, dead lift, bench press, back squat, front squat, and jump squat.

Results

Simple Pearson correlations indicated the validity of the device (0.982, 0.971, 0.973, and 0.982 for PV, AV, PP, and AP respectively) and ranged from 0.868 to 0.998 for the 6 exercises. The test-retest reliability of the EFTS was shown by lack of significant change in the Pearson correlation (<0.3% for each variable) between the 2 sessions. The multiple count error rate was 2.0% and the missed count error rate was 2.1%.

Conclusions

The validity and reliability of the EFTS were classified as excellent across all variables and exercises with only one exercise showing a slight influence by the velocity of the movement.

Do tattoos impair sweating?

23-08-2019 – Samuel Chalmers, Amy E. Harwood, Nathan B. Morris, Ollie Jay

Editorial

Hand and wrist OA in elite former cricket and rugby union players

20-06-2019 – Gordon S. Waddington

Editorial

Subgroup characteristics of patients with chronic ankle instability in primary care

18-03-2019 – Adinda K.E. Mailuhu, Edwin H.G. Oei, John M. van Ochten, Patrick J.E. Bindels, Sita M.A. Bierma-Zeinstra, Marienke van Middelkoop

Journal Article

Objectives

To examine clinical and radiological characteristics of participants with an ankle sprain in general practice, classified into subgroups of a previously described chronic ankle instability (CAI) model.

Design

Cross-sectional study.

Methods

206 participants, who visited their general practitioner with a lateral ankle sprain 6–12 months before inclusion, completed a questionnaire, physical examination, radiography and magnetic resonance imaging. They were classified into three subgroups of the previously described CAI-model: mechanical instability (MI), perceived instability (PI) and recurrent sprains (RS). Regression analyses were applied to evaluate differences in subgroup characteristics.

Results

A total of 192 participants were eligible to be classified into the model. Of these participants, 153 participants were classified into the subgroups and 39 could not be classified. With overlap between the subgroups and patients falling into more than one subgroup, 59 were classified having MI, 145 having PI and 30 having RS. Participants with RS and PI were more often sports participants (OR 6.83;95%CI 1.35–34.56 and OR 4.44;95%CI1.06–18.63 respectively) than participants without RS and PI. Participants with MI more often had a tenderness on palpation of the anterior talofibular ligament (OR 4.09;95%CI 1.91–8.72) and a KL-score ≥ 1 in the talonavicular joint on X-ray (OR 2.24;95%CI 1.09–4.58), compared to participants without MI.

Conclusions

Sports participation, tenderness on palpation of the anterior talofibular ligament and early signs of osteoarthritis were variables that discriminated between subgroups of CAI. However, further research is mandatory in order to examine the usefulness of the CAI model in relation to prognosis and suitable intervention.

The prevalence of hand and wrist osteoarthritis in elite former cricket and rugby union players

04-04-2019 – Mary E. Jones, Madeleine A.M. Davies, Karishma Shah, Simon Kemp, Nick Peirce, Kirsten M. Leyland, Keith A. Stokes, Andrew D. Judge, Julia L. Newton, Dominic Furniss, Nigel K. Arden

Journal Article

Objectives

This study aimed to determine the prevalence of hand and wrist osteoarthritis in former elite cricket and rugby union players, by sport and playing position, and to define the prevalence of severe hand injury, and its association with hand osteoarthritis.

Design

Cross-sectional.

Methods

Data from cross-sectional studies of former elite male cricket and rugby players were used to determine the prevalence of hand pain, physician-diagnosed osteoarthritis, and previous severe injury. Multivariable logistic regression was used to determine the association of previous injury with pain and osteoarthritis.

Results

Data from 200 cricketers and 229 rugby players were available. Complete case analysis resulted in 127 cricketers and 140 rugby players. Hand pain was more prevalent amongst cricketers (19.7%) than rugby players (10.0%). The prevalence did not differ between cricket and rugby players for hand osteoarthritis (2.4% and 3.6%), wrist osteoarthritis (1.6% and 2.1%), or previous severe hand injury (36.2% and 31.4%). No significant association between previous hand injury and pain or osteoarthritis was identified in either sport.

Conclusions

Former elite cricketers reported more hand pain than rugby players. No significant association was found between self-reported severe injury and hand osteoarthritis in either cohort, potentially indicating that risk factors aside from injury may be more prominent in the development of hand osteoarthritis.

A novel role of probiotics in improving host defence of elite rugby union athlete: A double blind randomised controlled trial

23-04-2019 – Kate L. Pumpa, Andrew J. McKune, Joanna Harnett

Journal Article

Objective

To examine the effects of a probiotic protocol on the incidence and severity of respiratory and gastrointestinal infections in elite rugby union athletes across an international competition season. Associations were also investigated between salivary biomarkers of stress (cortisol, alpha-amylase) and mucosal immunity (secretory(s)-Ig
A).

Design

A double-blind RCT was conducted over 27-weeks, divided into three stages: (1) control period; (2) domestic competition; and (3) international competition.

Methods

Athletes were assigned a probiotic (n = 9) or placebo (n = 10) supplement. Ultrabiotic 60™ or placebo was taken with food twice daily for 17 weeks and SB Floractiv™ 250 mg added twice daily during stage three.

Results

Five infections were diagnosed by the team sports physician across the 27-weeks, three within the intervention period in athletes randomised to the placebo group. No significant group x time interaction effects for salivary cortisol, alpha-amylase or s-Ig
A were identified over the 27-week time period, although a significant main effect for group and time was identified for salivary cortisol, alpha-amylase, and s-Ig
A (p < 0.05 for all). When considering stage, significant differences were identified in stage one with s-Ig
A lower in the probiotic group (p = 0.015). In stage two and three, salivary cortisol was higher in the probiotic group (p = 0.016 and p = 0.001 respectively), and salivary alpha-amylase was higher in the probiotic group in stage three (p = 0.007).

Conclusion

The probiotic protocol used in this study was associated with an increase in salivary alpha-amylase supporting its possible role as a host defence peptide.

Achilles tendon morphology assessed using image based spatial frequency analysis is altered among healthy elite adolescent athletes compared to recreationally active controls

20-04-2019 – Michael Cassel, Lucie Risch, Frank Mayer, Hannes Kaplick, Aaron Engel, Kornelia Kulig, Greg Bashford

Journal Article

Objectives

Although expected, tendon adaptations in adolescent elite athletes have been underreported. Morphologically, adaptations may occur by an increase in collagen fiber density and/or organization. These characteristics can be captured using spatial frequency parameters extracted from ultrasound images. This study aims to compare Achilles tendon (AT) morphology among sports-specific cohorts of elite adolescent athletes and to compare these findings to recreationally active controls by use of spatial frequency analysis.

Design

Cross-sectional observational study.

Method

In total, 334 healthy adolescent athletes from four sport categories (ball, combat, endurance, explosive strength) and 35 healthy controls were included. Longitudinal ultrasound scans were performed at the AT insertion and midportion. Intra-tendinous-morphology was quantified by performing spatial frequency analysis assessing eight parameters at standardized ROIs. Increased values in five parameters suggest a higher structural organization, and in two parameters higher fiber density. One parameter represents a quotient combining both organization and fiber density.

Results

Among athletes, only ball sport athletes exhibited an increase in one summative parameter at pre-insertion site compared to athletes from other sport categories. When compared to athletes, controls had significantly higher values of four parameters at pre-insertion and three parameters at midportion site reflecting differences in both, fiber organization and density.

Conclusions

Intra-tendinous-morphology was similar in all groups of adolescent athletes. Higher values found in non-athletes might suggest higher AT fiber density and organization. It is yet unclear whether the lesser structural organization in young athletes represents initial AT pathology, or a physiological adaptive response at the fiber cross-linking level.

Injury prevention strategies specific to pre-elite athletes competing in Olympic and professional sports — A systematic review

02-04-2019 – Erin A. Smyth, Phillip Newman, Gordon Waddington, Juanita R. Weissensteiner, Michael K. Drew

Journal Article, Review

Objectives

To describe and evaluate injury prevention interventions for pre-elite athletes who compete in an Olympic or professional sport.

Design

Systematic review.

Methods

This review was prospectively registered (PROSPERO CRD42017065083) and a systematic electronic search was conducted in May 2017. The following inclusion criteria were applied: (1) studies including and analysing data specific to pre-elite athletes (determined by the T3/T4 levels of the FTEM model); (2) featured injury prevention interventions; (3) provided sufficient data related to injury such that the effect can be analysed e.g. injury rates, incidence, prevalence, injury rate ratios; (4) featured randomised and non-randomised controlled trials or prospective cohorts.

Results

A total of 13,480 articles were retrieved with 121 titles identified and 11 studies satisfying the inclusion criteria. No studies demonstrated a low risk of bias. Four different interventions were identified: exercise (n = 7, 64%), psychological (n = 2, 18%), equipment (n = 1, 9%), nutrition (n = 1, 9%). Of the seven exercise interventions, four showed a protective effect and three found no significant effect, providing conflicting evidence. Caution is advised due to high risk of bias, low intervention reporting and minimal evidence for implementation planning in all seven studies.

Conclusions

There is limited evidence from level 2 and 3 studies suggesting exercise and psychology interventions may prevent injury in pre-elite athletes. There is an absence of evidence to support the use of equipment and nutrition interventions in pre-elite athletes. There is a need for quality research designs confirming the clinical impact of existing injury prevention interventions for pre-elite athletes.

Prevalence of sports-related injuries in paralympic judo: An exploratory study

14-04-2019 – Kristina Fagher, Osman Hassan Ahmed, Nicolina Pernheim, Emma Varkey

Journal Article

Objectives

The aim was to assess the 1-year retrospective prevalence of athletes reporting a sports-related injury among Paralympic judokas with visual impairment (VI), and to identify any associations between injury, vision class, gender and weight category.

Design

Cross-sectional retrospective study.

Methods

The data were collected through an adapted questionnaire given to athletes with VI during an international training camp. A total of 45 Paralympic judokas answered the questionnaire. Descriptive statistics and chi-square statistics (p < 0.05) were used to analyse the data. Spearman’s correlation was used to analyse multiple injuries.

Results

Thirty-eight of the athletes reported an injury, giving a 1-year prevalence of 84% (95% CI 71–93). Male athletes reported significantly more injuries compared to female athletes (p = 0.023). Over two thirds of the injuries (71%; 95% CI 55–83) had a traumatic onset. The majority of injuries (74%; 95% CI 58–85) occurred during judo training, and in the standing technique tachi waza (82%; 95% CI 66–91). The shoulder was the most single affected body location (29%). Forty-five percent of the injuries led to a time loss from sport for more than three weeks, and 40% of judokas reported multiple injuries.

Conclusions

The results from this study demonstrate a high prevalence of mainly traumatic and severe sports-related injuries amongst athletes with VI participating in Paralympic judo. A first step towards prevention could be to minimize the time in tachi waza. However, to improve sports safety and to develop effective strategies for injury prevention, more comprehensive epidemiological studies, and also technical studies assessing injury mechanisms are warranted.

Repeated muscle glycogen supercompensation with four days’ recovery between exhaustive exercise

04-04-2019 – Thomas M. Doering, Gregory R. Cox, José L. Areta, Vernon G. Coffey

Journal Article

Objectives

To determine if a 4 d period of high carbohydrate intake can supercompensate muscle glycogen and exercise work capacity on back-to-back occasions.

Design

Seven trained cyclists (6 male, VO2peak: 57 ± 4 m
L kg−1 min−1) completed a 9-d experimental period, consisting of three intermittent exhaustive cycling trials on days 1 (trial 1), 5 (trial 2) and 9 (trial 3). Following trial 1 cyclists were fed a high carbohydrate diet (˜10 g kg−1 day−1) for eight days to assess their capacity to repeatedly supercompensate muscle glycogen with 4 d recovery.

Methods

A resting muscle biopsy was obtained prior to each trial consisting of 2 min work intervals (90–60% peak power output) interspersed with 2 min recovery (40% peak power output) repeated until exhaustion. Each 72-h period between trial days included two days of low volume cycling and a rest day. Resting muscle glycogen and total work completed was determined for each trial day.

Results

Baseline muscle glycogen on day 1 (583.6 ± 111.0 mmol kg−1 dry mass) was supercompensated on day 5 (835.1 ± 112.8 mmol kg−1 dry mass; p = 0.04, d = 2.25) and again on day 9 (848.3 ± 111.4 mmol kg−1 dry mass; p = 0.01, d = 2.38). Total cycling work capacity increased from trial 1 to trial 2 (+8.7 ± 5.4 k
J kg−1; p = 0.01; d = 1.41); a large effect was observed in trial 3 compared to trial 1 (+6.4 ± 6.8 k
J kg−1; p = 0.10; d = 1.10).

Conclusions

A 4 d high carbohydrate feeding strategy is sufficient to repeatedly supercompensate muscle glycogen content following exhaustive exercise and results in enhanced work capacity.

Brief in-play cooling breaks reduce thermal strain during football in hot conditions

04-06-2019 – Samuel Chalmers, Jason Siegler, Ric Lovell, Grant Lynch, Warren Gregson, Paul Marshall, Ollie Jay

Journal Article

Objectives

The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches.

Design

Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT.

Methods

Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOLwater), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption and the application of an ice towel around the neck (COOLtowel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HTextended).

Results

The difference in rectal temperature change was significantly lower in the COOLwater (−0.25 °C), COOLtowel (−0.28 °C), and HTextended (−0.21 °C) trials in comparison to the REG (all p < 0.05). Exercising heart rate and session rating of perceived exertion was lower in the COOLwater (−13 bpm; −1.4 au), COOLtowel (−10 bpm; −1.3 au), and HTextended (−8 bpm; −0.9 au) trials in comparison to the REG trial (all p < 0.05). The cooling interventions did not significantly change skin temperature or thermal sensation in comparison to the REG (all p > 0.05).

Conclusions

All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.

Flexible learning spaces reduce sedentary time in adolescents

23-03-2019 – Katharina E. Kariippanon, Dylan P. Cliff, Anthony D. Okely, Anne-Maree Parrish

Journal Article

Objectives

Many schools internationally are replacing traditional classrooms (TC) with innovative flexible learning spaces (FLS) to improve academic outcomes. Via a stealth approach, there may be additional unintended health benefits if students reduce their total and prolonged sitting. The aim of this study was to compare student sitting patterns between TC and FLS.

Design

School-based cross-over trial.

Methods

Students at nine secondary schools (n = 191, M age = 13.2 ± 1.0 years) wore activ
PAL accelerometers in both a traditionally furnished and arranged classroom (TC), and a FLS containing a variety of furniture and layout options, utilizing student-centered pedagogies, for the duration of one double classroom lesson (M = 76 min). The lesson content and teacher were consistent across both conditions. Data were analyzed using multilevel mixed-effects linear regression.

Results

In FLS, students spent less class time sitting (mean = 18%; 95% CI: −20.8, −15.0), and accumulated more breaks in sitting (2.1; 95% CI: 0.8, 3.5 per 60 min), more bouts of intermittent (≤9 min) sitting (2.2; 95% CI: 0.8, 3.6 per 60 min), and fewer bouts of prolonged (≤30 min) sitting (−0.2; 95% CI: −0.3, −0.1 per 60 min), than in TC. Students also spent more class time standing (15%; 95% CI: 12.7, 18.0) and stepping (3%; 95% CI: 2.0, 3.1) in FLS than TC.

Conclusion

The results suggest that, by stealth, elements of FLS including a variety of furniture and resources, and greater use of student-centered pedagogies, facilitate improvements in adolescents’ sedentary profiles during class time. This may translate into beneficial health impacts over a longer period given the health benefits of reducing total and breaking up prolonged sitting.

A source of systematic bias in self-reported physical activity: The cutpoint bias hypothesis

09-04-2019 – Tim S. Olds, Sjaan R. Gomersall, Spencer T. Olds, Kate Ridley

Journal Article

Objectives

Estimates of adults’ moderate-to-vigorous physical activity (MVPA) based on self-report are generally higher than estimates derived from criterion measures. This study examines a possible explanation for part of this discrepancy: the cutpoint bias hypothesis. This hypothesis proposes that inter- and intra-individual variability in energy expenditure, combined with the fact that adults perform a high proportion of daily activities at or just above the traditional 3 MET cutpoint, result in systematic over-estimates of MVPA.

Design

Cross-sectional.

Methods

Time-use recalls (n = 6862) were collected using the Multimedia Activity Recall for Children and Adults from 2210 adults (1215 female, age 16–93 years) from 16 studies conducted in Australia and New Zealand between 2008-2017. Minutes spent in MVPA were estimated using models with varying levels of intra- and inter-individual (total variability) Unadjusted (0% total variability), Low (11.9%), Best Guess (20.7%), and High (30.0%).

Results

In the Unadjusted model, participants accumulated an average of 129 (standard deviation 127) min/day of MVPA. Estimated MVPA was 98 (110), 99 (107) and 108 (107) min/day in the Low, Best Guess and High variability models, respectively, with intra-class correlation coefficients with the Unadjusted model ranging from 0.78 to 0.83.

Conclusions

These findings support the hypothesis of a cutpoint bias, which probably contributes to the large disparities seen between self-reported and criterion measures of MVPA. Future studies are needed to confirm these findings using other self-report instruments and in other populations.

Muscle strength field-based tests to identify European adolescents at risk of metabolic syndrome: The HELENA study

08-05-2019 – José Castro-Piñero, Kelly R. Laurson, Enrique G. Artero, Francisco B Ortega, Idoia Labayen, Azahara I. Ruperez, Mahmoud Zaqout, Yannis Manios, Jeremy Vanhelst, Ascension Marcos, Angela Polito, Marcela Gonzalez-Gross, Kurt Widhalm, Luis A Moreno, Angel Gutierrez, Jonatan R Ruiz

Journal Article

Objectives

To determine whether handgrip strength (HG) and/or standing long jump (SLJ) are capable of detecting risk of metabolic syndrome (Met
S) in European adolescents, and to identify age- and sex-specific cut points for these tests.

Design

Cross-sectional study.

Methods

Participants included 969 (aged 12.5–17.5 years old) adolescents from 9 European countries (n = 520 girls). Absolute and relative HG and SLJ tests were used to assess upper and lower muscle strength, respectively. Met
S status was determined using the age- and sex-specific cut points proposed by Jolliffe and Janssen´s, Additionally, we computed a continuous cardiometabolic risk index with the average z-score of four cardiometabolic risk factors: Wait circumference, mean arterial pressure, triglycerides/high-density lipoprotein cholesterol, and fasting insulin.

Results

The prevalence of Met
S was 3.1% in European adolescents. Relative HG and absolute SLJ were the best tests for detecting the presence of Met
S (Area under the receiver operating characteristic (AUC) = 0.799, 95%CI:0.773–0.824; and AUC = 0.695 95%CI:0.665–0.724), respectively) and elevated cardiometabolic risk index (AUC = 0.873, 95%CI:0.838–0.902; and AUC = 0.728 95%CI:0.698–0.756), respectively) and, regardless of cardiorespiratory fitness. We provide age- and sex-specific cut points of upper and lower muscle strength for European adolescents to identify the presence of Met
S and elevated cardiometabolic risk index.

Conclusions

The proposed health-related cut points could be used as a starting point to define health-related levels of upper and lower muscle strength in adolescents. Likewise, the diagnostic statistics provided herein can be used to offer feedback to adolescents, parents, and education and health professionals about what it means to meet or fail test standards.

The A + FMS cluster randomized controlled trial: An assessment-based intervention on fundamental movement skills and psychosocial outcomes in primary schoolchildren

06-06-2019 – Cecilia H.S. Chan, Amy S.C. Ha, Johan Y.Y. Ng, David R. Lubans

Journal Article

Objectives

To evaluate the effectiveness of an assessment-based intervention that emphasizes fun, mastery, and support (A + FMS) on primary schoolchildren’s fundamental movement skills (FMS), perceptions of physical and movement skill competence, teacher support and enjoyment.

Design

Cluster randomized controlled trial.

Methods

Ten clusters (classes) (n = 282; mean age 8.4 years, SD 0.56) were randomised to the A + FMS or wait-list control group in a 1:1 ratio. Teachers in the A + FMS group were required to attend six hours of training and integrate 550 min of assessment for learning strategies into their PE lessons for up to a maximum of 13 weeks. FMS competence in jump, skip, hop, overhand throw, dribble and catch was the primary outcome assessed using the Test of Gross Motor Development-3rd Edition. Secondary outcome measures included perceptions of physical and FMS competence, teacher support, and student enjoyment using questionnaires. Multilevel modelling for the analysis of clustered data was used to determine the effectiveness of the intervention.

Results

Significant intervention effects were found for locomotor skills (adjusted mean difference, 2.47 units; Cohen’s d = 0.76), overall FMS competence (3.72 units; Cohen’s d = 0.93) and perceived teacher support (0.21 units; Cohen’s d = 0.05). However, there was a group-by-time effect for perceived physical competence (−0.16 units; Cohen’s d = −0.07) in favouring of the control group.

Conclusions

An assessment-based teacher-led FMS intervention was effective in improving FMS proficiency in primary schoolchildren. The results highlight the need for increased teacher support to develop positive self-perceptions of competence while promoting children’s FMS.

Trial registration CUHK_CCRB00479.

Effects of different protocols of high intensity interval training for VO2max improvements in adults: A meta-analysis of randomised controlled trials

09-02-2019 – Daizong Wen, Till Utesch, Jun Wu, Samuel Robertson, John Liu, Guopeng Hu, Haichun Chen

Journal Article, Review

Objectives

To examine the effects of different protocols of high-intensity interval training (HIIT) on VO2max improvements in healthy, overweight/obese and athletic adults, based on the classifications of work intervals, session volumes and training periods.

Design

Systematic review and meta-analysis.

Methods

PubMed, Scopus, Medline, and Web of Science databases were searched up to April 2018. Inclusion criteria were randomised controlled trials; healthy, overweight/obese or athletic adults; examined pre- and post-training VO2max/peak; HIIT in comparison to control or moderate intensity continuous training (MICT) groups.

Results

Fifty-three studies met the eligibility criteria. Overall, the degree of change in VO2max induced by HIIT varied by populations (SMD = 0.41–1.81, p < 0.05). When compared to control groups, even short-intervals (≤30 s), low-volume (≤5 min) and short-term HIIT (≤4 weeks) elicited clear beneficial effects (SMD = 0.79–1.65, p < 0.05) on VO2max/peak. However, long-interval (≥2 min), high-volume (≥15 min) and moderate to long-term (≥4–12 weeks) HIIT displayed significantly larger effects on VO2max (SMD = 0.50–2.48, < 0.05). When compared to MICT, only long-interval (≥2 min), high-volume (≥15 min) and moderate to long-term (≥4–12 weeks) HIIT showed beneficial effects (SMD = 0.65–1.07, < 0.05).

Conclusions

Short-intervals (≤30 s), low-volume (≤5 min) and short-term (≤4 weeks) HIIT represent effective and time-efficient strategies for developing VO2max, especially for the general population. To maximize the training effects on VO2max, long-interval (≥2 min), high-volume (≥15 min) and moderate to long-term (≥4–12 weeks) HIIT are recommended.

Transitioning from club to national teams: Training and match load profiles of international footballers

25-03-2019 – Denny Noor, Alan McCall, Mark Jones, Craig Duncan, Fabian Ehrmann, Tim Meyer, Rob Duffield

Journal Article

Objectives

To quantify and profile the training and match loads of international footballers as they transition from club-to-camp-to-tournament contexts during multiple international tournaments.

Design

Retrospective single-cohort observational study.

Methods

External (session duration and count) and internal (session Rating of Perceived Exertion s-RPE) load data of all outfield players from the same national team were compared between club, pre-tournament camp and initial tournament phases of 3 recent international competitions. Further, load profiles were compared between each phase based on the acute:chronic (A/C) ratio using a 7 to 21-day ratio.

Results

Moderate-to-large effect sizes existed for increased number of sessions (ES = 1.92; 90% CI: 1.56, 2.27) and s-RPE training load (ES = 1.16; 0.84, 1.48) from club to camp. Conversely, transitioning from camp-to-tournament showed very large effects for decreased number of training sessions (ES = −3.17; −3.47, −2.86) and s-RPE training load (ES = −2.05; −2.35, −1.75), alongside increased number of matches (ES = 1.87; 1.55, 2.18) and s-RPE match load (ES = 1.57; 1.25, 1.89). Consequently, a moderate effect was evident for increased A/C ratio during the club-to-camp transition (ES = 1.02; 0.70, 1.33), while a moderate decrease in the A/C ratio occurred during the tournament (ES = −0.76; −1.06, −0.46).

Conclusions

International footballers showed expected increased training load when entering into pre-tournament camps, predominately via increased number of training sessions. Subsequent reductions in training volume coincide with increased match volume, though total load decreases. Such profiles provide insight into load accumulation transitioning from club to national teams in international footballers.

Mid-flight trunk flexion and extension altered segment and lower extremity joint movements and subsequent landing mechanics

25-03-2019 – Daniel J. Davis, Taylour J. Hinshaw, Meghan L. Critchley, Boyi Dai

Journal Article

Objectives

To assess the effect of mid-flight trunk flexion and extension on the movements of body segments and lower extremity joints and subsequent landing mechanics during a jump-landing task.

Design

Participants performed three jump-landing conditions in a randomized order.

Methods

Forty-one participants completed jump-landing trials when performing three different mid-flight trunk motion: reaching forward, reaching up, and reaching backward. Whole-body kinematic and ground reaction force data were collected.

Results

The reaching backward condition resulted in a more posteriorly positioned upper body center of mass (COM) and more anteriorly positioned pelvis COM, legs COM, hip, and knee joint positions relative to the whole-body COM in flight and at initial contact of landing. The reaching backward condition showed the least hip flexion and ankle plantarflexion angles at initial contact as well as the least hip and knee flexion angles and the greatest ankle dorsiflexion angles at 100 ms after landing. The reaching backward condition also demonstrated the greatest peak posterior ground reaction forces, peak and average knee extension moments, peak and average hip flexion moments, and peak knee varus moments within the first 100 ms after landing. Opposite changes were observed for the reaching forward condition.

Conclusions

Mid-flight trunk extension resulted in body postures that predisposed individuals to land with increased knee extension and varus moments and decreased knee flexion angles, which are indirectly associated with increased ACL loading. These findings may help to understand altered trunk motion during certain ACL injury events and provide information for developing jump-landing training strategies.

Isolated ingestion of caffeine and sodium bicarbonate on repeated sprint performance: A systematic review and meta-analysis

01-05-2019 – João P. Lopes-Silva, Hui C. Choo, Emerson Franchini, Chris R. Abbiss

Journal Article, Review

Objectives

This study is a systematic review and meta-analysis aimed at investigating the isolated effects of caffeine and sodium bicarbonate (Na
HCO3) ingestion on repeated sprint ability (RSA).

Methods

Following a search through PubMed and Scopus, 13 studies (7 with caffeine and 6 with Na
HCO3) were found to meet inclusion criteria. Random-effects of standardized mean difference (SMD) for total work and best sprint performance was examined. Study quality was assessed using Qual
Syst.

Results

The meta-analysis indicated that caffeine ingestion did not improve the total work done (weighted average effect size Hedges’s g = −0.01, 95%CI: −0.32 to 0.31, p = 0.97), best sprint (weighted average effect size Hedges’s g = −0.02, 95% CI: −0.32 to 0.27; p = 0.87) or last sprint performance (weighed average effect size Hedge’s g = −0.27, 95%CI: −0.68 to 0.14; p = 0.20), when compared with a placebo condition. Similarly, Na
HCO3 ingestion did not improve the total work done (weighted average effect size Hedges’s g = 0.43, 95% CI: −0.11 to 0.97, p = 0.12), best sprint (weighted average effect size Hedges’s g = 0.02, 95% CI −0.30 to 0.34; p = 0.90) or last sprint performance (weighted average effect size Hedge’s g = 0.20, 95%CI: −0.13 to 0.52, p = 0.14), compared with a placebo condition. Quality assessment of selected articles was classified as strong.

Conclusion

This meta-analysis provides evidence that repeated sprint ability is not affected by acute ingestion of caffeine or Na
HCO3.

Normalization influences knee abduction moment results: Could it influence ACL-injury research, too? Response to Letter to the Editor by Dr. Timothy E. Hewett

01-04-2019 – Marc F. Norcross

Letter

Functional polymorphisms within the inflammatory pathway regulate expression of extracellular matrix components in a genetic risk dependent model for anterior cruciate ligament injuries

10-08-2019 – Mathijs A.M. Suijkerbuijk, Marco Ponzetti, Masouda Rahim, Michael Posthumus, Charlotte K. Häger, Evalena Stattin, Kjell G. Nilsson, Anna Teti, Duncan E. Meuffels, Bram J.C. van der Eerden, Malcolm Collins, Alison V. September

Journal Article

Objectives

To investigate the functional effect of genetic polymorphisms of the inflammatory pathway on structural extracellular matrix components (ECM) and the susceptibility to an anterior cruciate ligament (ACL) injury.

Design

Laboratory study, case–control study.

Methods

Eight healthy participants were genotyped for interleukin (IL)1B rs16944 C > T and IL6 rs1800795 G > C and classified into genetic risk profile groups. Differences in type I collagen (COL1A1), type V collagen (COL5A1), biglycan (BGN) and decorin (DCN) gene expression were measured in fibroblasts either unstimulated or following IL-1β, IL-6 or tumor necrosis factor (TNF)-α treatment.

Moreover, a genetic association study was conducted in: (i) a Swedish cohort comprised of 116 asymptomatic controls (CON) and 79 ACL ruptures and (ii) a South African cohort of 100 CONs and 98 ACLs. Participants were genotyped for COL5A1 rs12722 C > T, IL1B rs16944 C > T, IL6 rs1800795 G > C and IL6R rs2228145 G > C.

Results

IL1B high-risk fibroblasts had decreased BGN (p = 0.020) and COL5A1 (p = 0.012) levels after IL-1β stimulation and expressed less COL5A1 (p = 0.042) following TNF-α treatment. Similarly, unstimulated IL6 high-risk fibroblasts had lower COL5A1 (p = 0.012) levels than IL6 low-risk fibroblasts.

In the genetic association study, the COL5A1-IL1B-IL6 T–C–G (p = 0.034, Haplo-score 2.1) and the COL5A1-IL1B-IL6R T–C–A (p = 0.044, Haplo-score: 2.0) combinations were associated with an increased susceptibility to ACL injury in the Swedish cohort when only male participants were evaluated.

Conclusions

This study shows that polymorphisms within genes of the inflammatory pathway modulate the expression of structural and fibril-associated ECM components in a genetic risk depended manner, contributing to an increased susceptibility to ACL injuries.

Sports Participation, Health Behaviours, and Body Fat during Childhood and Early Adolescence: A Multiple Mediation

21-08-2019 – Stewart A. Vella, Lauren A. Gardner, Byron Kemp, Matthew J. Schweickle, Dylan P. Cliff

Journal Article

Objectives

The aim of this study was to simultaneously explore multiple pathways through which sports participation during childhood and adolescence may be associated with adiposity over time.

Design

Data were drawn from the Kindergarten cohort of the Longitudinal Study of Australian Children. A total of 4286 children provided sports participation data at age 10 years and were followed up 24 and 48 months later.

Method

Time spent in organised sports at age 10 years and time spent in physical activity at age 12 years were measured via parental-reported time-use diary. Dietary behaviours were self-reported at age 12 years. Screen time was parent-reported. Body fat was measured at age 14 using bioelectrical impedance analysis. Two parallel multiple mediation models were tested to examine the longitudinal associations between sport participation at age 10 and body fat at age 14 via the mediating variables of physical activity, screen time, and dietary behaviours. One model was run for all participants, and a second model was run only for those participants who reported participating in organised sports.

Results

There were no significant indirect relationships between sports participation and body fat via any of the mediating variables in the total sample, or among sport participants.

Conclusions

There is a dearth of evidence to support substantial rhetoric and policy to promote organised sports programs as public health initiatives in their current form during childhood and adolescence. Better quality evidence is needed, however, modifications to sport programs may be necessary to elucidate meaningful benefits for adiposity.

Epidemiology of hospital-treated cricket injuries sustained by women from 2002–2003 to 2013–2014 in Victoria, Australia

20-08-2019 – Nirmala Kanthi Panagodage Perera, Joanne L. Kemp, Corey Joseph, Caroline F. Finch

Journal Article

Objectives

To present the first comprehensive epidemiological profile of hospital-treated injuries sustained by female cricketers from 2002–2003 to 2013–2014 in Victoria, Australia.

Design

Analysis of routinely collected hospital data (detailed case-series).

Methods

A retrospective analysis of hospital-treatment data associated with cricket injuries sustained by women between 1 July 2002 and 30 June 2014, inclusive were extracted from databases held by the Victorian Injury Surveillance Unit in Australia.

Results

Over the 12-year period, 668 cases were treated in Victoria. Of these, 547 were emergency department (ED)-presentations. There were 121 hospital-admissions, of which, the length of stay was <2 days for 78.5% cases. All cases were treated and released, and no fatalities were reported. The 10–14 year age group most frequently presented to ED (19.9%) and were most commonly admitted to hospital (16.5% of the total admissions). Fractures were the most common cause of hospital-admissions (47.1%) but only accounted for 17.2% of the ED-presentations. Dislocations, sprains and strains, were the most common (36.4%) cause of ED-presentations. The head was the most commonly injured anatomical location (27.8% of ED-presentations and 28.1% of hospital-admissions), followed by the wrist and hand (27.8% ED-presentations and 17.4% hospital-admissions).

Conclusions

These findings provide the first overview of the nature of injuries requiring hospital attendance in female cricketers, and a foundation to inform the development of targeted injury prevention programs for female cricketers.

Rowers with a recent history of low back pain engage different regions of the lumbar erector spinae during rowing

03-08-2019 – Eduardo Martinez-Valdes, Fiona Wilson, Neil Fleming, Sarah-Jane McDonnell, Alex Horgan, Deborah Falla

Journal Article

Objectives

Despite the high prevalence of low back pain (LBP) in rowers, there are few studies investigating changes in lumbar muscle activation in rowers with a recent history of LBP. Such knowledge is relevant to understand potential mechanisms contributing to the maintenance and recurrence of LBP in rowers. For the first time, we evaluate the spatial distribution of erector spinae (ES) activity in rowers with and without a recent history of LBP, using a novel application of high-density surface electromyography (HDEMG).

Design

Cross-sectional study.

Methods

Asymptomatic rowers (N = 10) and rowers with a recent history of LBP (N = 8) performed 7 × 4-min exercise bouts (rowing ergometer) until volitional exhaustion. HDEMG signals were acquired bilaterally over the lumbar ES and the root mean square (RMS) amplitude and entropy were analyzed. In addition, the y-axis coordinate of the barycentre (RMS-map) was used to assess changes in ES spatial activation.

Results

As the load increased, rowers with LBP showed higher amplitude (p < 0.01) and less complexity (entropy) of the HDEMG signals (p < 0.001). In addition, rowers with LBP showed opposite displacements of the barycentre, specifically showing a caudal shift of muscle activity at high intensities (p < 0.001).

Conclusions

Both the magnitude of activation and distribution of ES activity were altered in rowers with a recent history of LBP. The lower complexity of signals together with the caudal displacements of the barycentre suggest an inefficient recruitment of the ES as the load progressed. Modification of the rowing technique in conjunction with feedback from HDEMG might prove useful in future studies.

Social cohesion and peer acceptance predict student-athletes’ attitudes toward health-risk behaviors: A within- and between-group investigation

28-07-2019 – Scott Graupensperger, Alex J. Benson, Bethany C. Bray, M. Blair Evans

Journal Article

Objectives

Collegiate student-athletes often engage in health-risk behaviors such as alcohol misuse and hazing, but the literature in this domain lacks evidence pertaining to how peers shape attitudes towards such behaviors. We investigated how peer acceptance and social cohesion relate to attitudes towards alcohol use, marijuana use, drinking and driving, playing through a concussion, performance enhancing substance use, and hazing.

Design

Cross-sectional survey.

Methods

Participants were 387 NCAA athletes from 23 intact teams. Multilevel modeling was used to examine the extent that health-risk attitudes clustered within teams and enabled us to disentangle individual-level and group-level effects of peer acceptance and social cohesion.

Results

Intraclass correlation coefficients revealed that health-risk attitudes clustered within teams. At the individual-level, student-athletes who perceived higher levels of peer acceptance, relative to teammates, held riskier attitudes towards alcohol use, playing through a concussion, and hazing. Meanwhile, those who perceived higher levels of social cohesion relative to teammates held less risky attitudes towards playing through a concussion. At the group-level, teams with greater peer acceptance held less risky attitudes towards playing through a concussion, whereas teams with greater social cohesion held riskier attitudes toward playing through a concussion.

Conclusions

These data indicated that health-risk behaviors may cluster within teams, and that peer acceptance and cohesiveness are differentially associated with attitudes toward risky behavior. Given that peer influence is a multilevel phenomenon, it is prudent that prevention efforts leverage social processes within teams, while reducing pressures to engage in risky behaviors.

Maintaining motivation and health among recreational runners: Panel study of factors associated with self-rated performance outcomes at competitions

07-08-2019 – Håkan Gauffin, Bo Tillander, Örjan Dahlström, Johan Lyth, Ben Raysmith, Jenny Jacobsson, Toomas Timpka

Journal Article

Objectives

To investigate health-related factors associated with self-rated race performance outcomes among recreational long-distance runners.

Design

Panel study.

Methods

Data were collected from runners one month before and after a community-level race event including distances from 8 to 42.2 km. The primary outcome measure was self-rated race performance outcome. The explanatory variables represented health complaints suffered during the build-up year, the pre-race month, and the race and among full marathon runners predicted objective performance outcome (mean pace equal to training pace or faster). Multiple logistic regression was used to determine factors associated with the self-rated performance outcome.

Results

Two-hundred forty-five runners (29%) provided complete data sets. Seventy-four percent of the runners reached their desired race performance outcome. Achievement of the performance outcome was more likely when having avoided illness during the build-up and pre-race periods (OR = 3.8; 95% CI:1.8–8.0, p < 0.001), having avoided per-race injury (OR=3.0; 95% CI:1.2–7.4, p = 0.02) and avoided per-race illness (OR = 4.1; 95% CI:1.3–15, p = 0.020). Having obtained the self-rated performance outcome was also associated with running a shorter distance (OR=3.6; 95% CI: 1.7–8.0, p = 0.001) and being younger than 50 years of age (OR = 2.4; 95% CI:1.1–5.3–8.3, p = 0.03). Having met the predicted objective performance outcome predisposed marathon runners to also obtain the self-rated performance outcome (OR = 4.7, 95% CI: 1.5–16, p < 0.01).

Conclusions

Having avoided illness during build-up and pre-race was positively associated with self-rated race performance outcome among recreational runners. Adjusting the desired performance outcomes with regard to recent illness and age may help recreational runners to more often achieve their goals and thereby prevent them from leaving the sport.

The effects of hyperoxia on repeated sprint cycling performance & muscle fatigue

25-07-2019 – Michael S. Porter, Jordan Fenton, Katharine E. Reed

Journal Article

Objectives

Hyperoxia (>21% oxygen) can evoke performance improvements in aerobic and anaerobic exercise. The aims of the current study were to determine the effects of breathing hyperoxic gas (fraction of inspired oxygen FiO2 1.00) on repeated cycle performance, and to assess the nature and extent of fatigue after intermittent sprinting.

Design & methods

Testing (n = 14 males) comprised two visits to the laboratory. Each session involved 10 × 15 s repeated cycle sprints breathing Fi
O2 1.00 (hyperoxia) or Fi
O2 0.21 (normoxia). Muscle fatigue was measured pre and post sprints using Maximal Voluntary Contraction (MVC), voluntary activation (VA) and potentiated doublet twitch (PTF). Blood lactate (BLa) was taken between sprints.

Paired samples t-tests were used to examine difference between conditions in power output (peak and mean Watts) and BLa. Two-way ANOVA was used to examine fatigue variables pre and post sprints according to condition.

Results

Mean power output was 4% greater in hyperoxia (p < 0.01), with no difference in peak power (p > 0.05). There was a significant increase in BLa in hyperoxia compared with normoxia (p < 0.01) in sprints 4 and 8, as well as meaningful difference in sprints 4–10. There was no significant difference in fatigue factors (MVC, VA and PTF) (p > 0.05) in response to the cycling, although a large drop in PTF occurred in both conditions.

Conclusion

Hyperoxia can elicit improvements in mean cycling power, with no significant change in post exercise muscle fatigue. Hyperoxia as a training aid may provide performance enhancing effects during repeated sprint cycling by reducing concurrent muscle fatigue, primarily via peripheral factors.

A 2.5u202fmin cold water immersion improves prolonged intermittent sprint performance

23-07-2019 – Mikel Egaña, Larry Jordan, Tommy Moriarty

Journal Article

Objectives

We investigated if cold water immersion (CWI) affects exercise performance during a prolonged intermittent sprint test (IST), designed to mimic activity patterns of team-sports.

Design

Randomized-crossover design.

Methods

Ten male team-sport players completed 3 IST protocols (two 40-min “halves” of repeated 2-min blocks consisting of a 8-s “all-out” sprint, 100-s active recovery and 12-s rest) on a cycle ergometer at normothermic conditions. Each “half” was separated by a 15 min recovery period of either: (i) passive rest, (ii) 5-min CWI at 8 °C (CWI-5) or (iii) 2.5-min CWI at 8 °C (CWI-2.5), in a random counterbalanced order.

Results

Physical performance, core temperature (Tcore) and heart rate were not different among conditions in the first half. In the passive rest trial, total work (TW) and peak power (PP) were lower during the second half (TW: 5.04 ± 1.11 k
J; PP: 929 ± 286 W) than the first half (TW: 5.66 ± 1.02 k
J; PP: 1009 ± 266 W); while TW and PP were not different between halves following CWI-5 (first half, TW: 5.34 ± 1.02 k
J, PP: 1016 ± 283 W; second half, TW: 5.19 ± 1.38 k
J; PP: 996 ± 318 W) and CWI-2.5 (first half, TW: 5.47 ± 1.19 k
J, PP: 966 ± 261 W; second half, TW: 5.25 ± 1.17 k
J; PP: 952 ± 231 W). Tcore was lower until the 20th minute of the second half after CWI-5 and CWI-2.5 compared with passive rest.

Conclusions

A post-exercise 2.5–5-min CWI attenuates the reductions in prolonged sprint performance that occur in the second half of team sports, due, at least partly, to reductions in core temperature and associated increase in heat storage.

Corrigendum to “Brief in-play cooling breaks reduce thermal strain during football in hot conditions” J. Sci. Med. Sport 22 (2019) 912–917

13-07-2019 – Samuel Chalmers, Jason Siegler, Ric Lovell, Grant Lynch, Warren Gregson, Paul Marshall, Ollie Jay

Published Erratum

Longitudinal associations among cardiorespiratory and muscular fitness, motor competence and objectively measured physical activity

16-07-2019 – T. Jaakkola, S. Yli-Piipari, M. Huhtiniemi, K. Salin, S. Seppälä, H. Hakonen, A. Gråstén

Journal Article

Objectives

This study aimed to investigate cross-lagged associations in motor competence, cardiorespiratory fitness, muscular fitness and accelerometer-based moderate-to-vigorous physical activity (MVPA) engagement.

Design

One-year prospective follow-up study.

Methods

A sample was 491 (275 girls; M at baseline = 11.27, SD = .32) Finnish physical education students. Students’ motor competence was assessed by (1) two-legged jumping from side to side test, (2) throwing-catching combination test and (3) 5-leaps test. Their cardiorespiratory fitness was analyzed by a 20-m shuttle run test and muscular fitness by curl-up and push-up tests. Additionally, students’ MVPA was measured objectively by hip-worn accelerometers.

Results

Results demonstrated that: (1) cardiorespiratory fitness measured at Grade 5 was the only significant predictor of later MVPA and this association appeared only in the boys’ group, (2) MVPA assessed at Grade 5 significantly predicted cardiorespiratory fitness in the girls’ group, (3) cardiorespiratory fitness collected at Grade 5 associated with muscular fitness, locomotor and stability skills in both girls and boys, and (4) locomotor skills measured at Grade 5 predicted significantly muscular fitness, locomotor and manipulative skills in both sex groups.

Conclusions

Elementary school years are important in providing students with experiences in physical activity (PA) which leads to improvements s in cardiorespiratory health. Additionally, this study showed that cardiorespiratory fitness collected at Grade 5 associated with later muscular fitness, and locomotor and stability skills in both sex groups. These findings are noteworthy because muscular fitness in youth has several health-related benefits and motor competence in childhood and adolescence has positive association with later PA engagement.

The impact of physical activity and sport on social outcomes among Aboriginal and Torres Strait Islander people: A systematic scoping review

10-07-2019 – Rona Macniven, Karla Canuto, Rachel Wilson, Adrian Bauman, John Evans

Journal Article, Review

Objectives

To identify and describe existing evidence of the impact of sport and physical activity programs on social outcomes among Aboriginal and Torres Strait Islander people.

Design

Systematic scoping review.

Methods

Nine scientific databases (MEDLINE, Scopus, SPORTSDiscus, Psyc
INFO, Informit, Database of Abstracts of Reviews of Effects (DARE), The Cochrane Library, The Campbell Library, Pro
Quest Dissertations and Theses) and grey literature were systematically searched for programs or activities that target Aboriginal and Torres Strait Islander people and use physical activity and sport participation to improve one or more of six social and community outcomes of: (i) education; (ii) employment; (iii) culture; (iv) social and emotional wellbeing; (v) life skills; (vi) crime reduction.

Results

Of the 1160 studies identified, 20 met the inclusion criteria and were published between 2003 and 2018. Most studies reported positive findings across multiple, broad outcomes of education (N = 11), employment (N = 1), culture (N = 9), social and emotional wellbeing (N = 12), life skills (N = 5) and crime reduction (N = 5). Some evidence was found for increased school attendance and improved self-esteem resulting from physical activity and sport participation as well as enhanced aspects of culture, such as cultural connections, connectedness, values and identity.

Conclusions

There is some evidence of benefit across the six social outcomes from physical activity and sport programs. This promotes their continuation and development, although critical appraisal of their methods is needed to better quantify benefits, as well as the generation of new evidence across indicators where gaps currently exist, particularly for employment and crime reduction outcomes.

Why exercise may be beneficial in concussion rehabilitation: A cellular perspective

28-07-2019 – Ryan T. Dech, Scott A. Bishop, J. Patrick Neary

Journal Article, Review

Introduction

Concussion diagnosis and rehabilitation management has become a prevalent area of research, and yet much is still unknown about these complex injuries. Historically, exercise prescription post-concussion was conservatively used for rehabilitation due to the suspected harmful effects that exercise can have on damaged neurons, and increase in symptoms. However, there has been a shift to implement exercise earlier into recovery as several studies have demonstrated positive outcomes.

Objective

The objective of this literature review is to update the reader about new advances in concussion research related to the beneficial effects of physical activity from both a neurometabolic and a broader physiological perspective, using gene expression as a vehicle to demonstrate why and how physical activity has the capacity to optimize recovery from a cellular perspective. To further this clinical guideline, the evidence must continue to support these positive outcomes from an inductive and deductive physiologic approach (i.e., the clinical evidence aligned from a micro- to macroscopic approach and vice versa).

Design

Narrative review.

Methods

Pubmed and Medline were used with the following key words: concussion and, physical activity, neurometabolic, gene regulation, trauma, nervous system, mild head injury, acute exercise, cellular physiology and pathophysiology.

Conclusion

It is our contention that understanding the cellular perspective will help guide clinical management, and promote research into post-concussion exercise.

A data-driven, meaningful, easy to interpret, standardised accelerometer outcome variable for global surveillance

11-07-2019 – Alex V. Rowlands, Lauren B. Sherar, Stuart J. Fairclough, Tom Yates, Charlotte L. Edwardson, Deirdre M. Harrington, Melanie J. Davies, Fehmidah Munir, Kamlesh Khunti, Victoria H. Stiles

Journal Article

Objectives

Our aim is to demonstrate how a data-driven accelerometer metric, the acceleration above which a person’s most active minutes are accumulated, can (a) quantify the prevalence of meeting current physical activity guidelines for global surveillance and (b) moving forward, could inform accelerometer-driven physical activity guidelines. Unlike cut-point methods, the metric is population-independent (e.g. age) and potentially comparable across datasets.

Design

Cross-sectional, secondary data analysis.

Methods

Analyses were carried out on five datasets using wrist-worn accelerometers: children (N = 145), adolescent girls (N = 1669), office workers (N = 114), pre- (N = 1218) and post- (N = 1316) menopausal women, and adults with type 2 diabetes (N = 475). Open-source software (GGIR) was used to generate the magnitude of acceleration above which a person’s most active 60, 30 and 2 min are accumulated: M60ACC; M30ACC and M2ACC, respectively.

Results

The proportion of participants with M60ACC (children) and M30ACC (adults) values higher than accelerations representative of brisk walking (i.e., moderate-to-vigorous physical activity) ranged from 17 to 68% in children and 15 to 81% in adults, tending to decline with age. The proportion of pre-and post-menopausal women with M2ACC values meeting thresholds for bone health ranged from 6 to 13%.

Conclusions

These metrics can be used for global surveillance of physical activity, including assessing prevalence of meeting current physical activity guidelines. As accelerometer and corresponding health data accumulate it will be possible to interpret the metrics relative to age- and sex- specific norms and derive evidence-based physical activity guidelines directly from accelerometer data for use in future global surveillance. This is where the potential advantages of these metrics lie.

Epidemiology of bone stress injuries in Australian high performance athletes: A retrospective cohort study

17-07-2019 – Gemma K. Ruddick, Gregory A. Lovell, Michael K. Drew, Kieran E. Fallon

Journal Article

Objectives

To examine the epidemiology of bone stress injuries in an elite sports institute.

Design

Retrospective cohort study at the Australian Institute of Sport.

Methods

A retrospective analysis of the clinical records contained within the Australian Institute of Sport Athlete Management System electronic database was performed. Records with Orchard Sports Injury Classification System codes relating to bone stress injuries and stress fractures were reviewed and descriptive statistics relating to sport, site of injury, athlete age, sex and activity were analysed.

Results

In the three-year period January 2014–2017, 11,942 injuries were recorded across 48 sports. 181 bone stress injuries (0.15% of all injuries) were recorded across 16 sports. BSIs in the foot and lumbar spine were the most common accounting for 30% and 23% of all the reported BSIs respectively. Gymnasts had a high frequency of lumbar spine stress injuries (n = 24, 51%) and rowers had a high frequency of rib stress injuries (n = 22, 88%). The most common location for stress injuries, equally distributed across a variety of sports, were in the foot (n = 54, 30%). Female athletes recorded more BSIs than males.

Conclusion

Across a three-year period, 0.15% of injuries were related to bone stress injuries. Almost double the cases were recorded in female athletes. Sport specific injury sites were observed in the dataset.

Does increased midsole bending stiffness of sport shoes redistribute lower limb joint work during running?

06-07-2019 – Sasa Cigoja, Colin R. Firminger, Michael J. Asmussen, Jared R. Fletcher, W. Brent Edwards, Benno M. Nigg

Journal Article

Objectives

To investigate if lower limb joint work is redistributed when running in a shoe with increased midsole bending stiffness compared to a control shoe.

Design

Within-subject with two conditions: (1) commercially available running shoe and (2) the same shoe with carbon fibre inserts to increase midsole bending stiffness.

Methods

Thirteen male, recreational runners ran on an instrumented treadmill at 3.5 m/s in each of the two shoe conditions while motion capture and force platform data were collected. Positive and negative metatarsophalangeal (MTP), ankle, knee, and hip joint work were calculated and statistically compared between conditions.

Results

Running in the stiff condition (with carbon fibre inserts) resulted in significantly more positive work and less negative work at the MTP joint, and less positive work at the knee joint.

Conclusions

Increased midsole bending stiffness resulted in a redistribution of positive lower limb joint work from the knee to the MTP joint. A larger MTP joint plantarflexor moment due to increased v
GRF at the instant of peak positive power and an earlier onset of MTP joint plantarflexion velocity were identified as the reasons for lower limb joint work redistribution.

Using the single leg squat as an assessment of stride leg knee mechanics in adolescent baseball pitchers

10-07-2019 – Kyle Wasserberger, Jeff Barfield, Adam Anz, James Andrews, Gretchen Oliver

Journal Article

Objectives

Lack of control of the lower extremity or trunk during single leg tasks is often associated with pathomechanic adaptations during the pitching motion which may increase the risk of pain and injury to the upper extremity. The objectives of the study were to determine the amount of variability in stride knee mechanics accounted for by compensations during a common movement assessment, the single leg squat (SLS) and to establish the usefulness of SLS as a screening tool for at-risk athletes.

Design

Cross-sectional design.

Methods

Sixty-one adolescent baseball pitchers performed a SLS on each leg. Participants performed three fastball pitches to a catcher at a regulation distance. Kinematic data were collected at 100 Hz using an electromagnetic tracking device.

Results

MANOVAs with follow-up one-way ANOVAs were used to examine the amount of variance in pitching knee mechanics explained by SLS compensations. At stride foot contact, there was a significant effect of SLS valgus angle on knee valgus angle (F1,51 = 23.16, p < 0.001, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” overflow=”scroll” class=”math”>ηp2=0.31) and valgus moment (F1,51 = 8.28, p = 0.006, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si2.gif” overflow=”scroll” class=”math”>ηp2=0.14). At ball release (BR), there was a significant effect of SLS valgus angle on flexion angle (F1,51 = 9.37, p = 0.004, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si3.gif” overflow=”scroll” class=”math”>ηp2=0.16) and valgus angle (F1,51 = 26.93, p < 0.001, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si4.gif” overflow=”scroll” class=”math”>ηp2=0.35). Examination of the average values occurring between SFC and BR, revealed a significant effect of SLS valgus angle on knee valgus angle (F1,51 = 30.91, p < 0.001, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si5.gif” overflow=”scroll” class=”math”>ηp2=0.38).

Conclusions

SLS compensations are potentially a useful screening tool for stride knee mechanics in adolescent baseball pitchers.

Sitting time and depression in young women over 12-years: The effect of physical activity

06-07-2019 – T.G. Pavey, W.J. Brown

Journal Article

Objectives

Lack of physical activity (PA) and prolonged sitting time (ST) are associated with increased risk of mortality and chronic illnesses, including depression. While there have been claims that the two risks are ‘independent’, their joint and stratified effects are unclear. The aim of this study was to explore the combined effects of physical activity and sitting time on the 12 year risk of depressive symptoms (DS) in young women.

Design

Cohort-9061 young participants in the Australian Longitudinal Study on Women’s Health completed triennial surveys from 2000 (age 22–27), to 2012.

Methods

Generalised Estimating Equation models were used to calculate the joint effects of PA and ST on DS, with <4 h/day of ST and the highest PA quartile as the reference categories. Relationships between PA and DS, and between ST and DS, were also examined after stratification by ST and PA respectively.

Results

In the adjusted joint effects model, compared with the reference category (low sitting, high PA), odds for DS were significantly higher in women who sat for >4, 6 and 8 h/day and reported doing no PA. In every physical activity category, women who sat for ≥10 h/day were at highest risk of DS (OR for lowest physical activity quartile, 1.72 95% CI = 1.38–2.14; OR for highest physical activity quartile, 1.49 95% CI = 1.16–1.91). After stratification by ST, odds of DS were reduced in women who reported any physical activity (compared with none), except when ST was >10 h/day. After stratification by physical activity, the increased risk of sitting 8–10 h/day was attenuated by any physical activity, but there was no reduction in risk of depressive symptoms with increasing PA levels in women who sat for ≥10 h per day.

Conclusions

These data suggest that there are both joint and stratified effects of too little activity and too much sitting on the risk of depressive symptoms in young women. High levels of PA are protective against the hazards of high ST at this life stage, except in women with very high levels of sitting.

Resistance training enhances delayed memory in healthy middle-aged and older adults: A randomised controlled trial

10-07-2019 – Kieran J. Marston, Jeremiah J. Peiffer, Stephanie R. Rainey-Smith, Nicole Gordon, Shaun Y. Teo, Simon M. Laws, Hamid R. Sohrabi, Ralph N. Martins, Belinda M. Brown

Journal Article

Objectives

High-intensity exercise is a potential therapeutic tool to postpone or prevent the onset of cognitive decline. However, there is a lack of sufficient evidence regarding the longitudinal effects of structured resistance training on cognitive function in healthy adults. The purpose of this study was to investigate the effect of two ecologically valid, intense 12-week resistance training programs on cognitive function in late middle-aged adults.

Design

Single-site parallel randomised controlled trial at the Department of Exercise Science strength and conditioning laboratory. Groups allocated by minimisation randomisation.

Methods

Forty-five healthy adults (age range = 41–69 years) were enrolled and randomised into (A) high-load, long rest resistance training (n = 14), or (B) moderate-load, short rest resistance training (n = 15) twice per week for 12 weeks, or a non-exercising control (n = 16). Follow-up within seven days. Data were collected September 2016–December 2017. Cognitive function assessed using the Cog
State computerised battery. Assessors were blinded to participant group allocation. Secondary outcomes were maximal muscle strength and body composition.

Results

Forty-four participants were analysed in 2018. Delayed verbal memory performance was improved (p = 0.02) in resistance training groups (g = 0.67–0.79) when compared to the control group, with no differences between training groups. Likewise, increases in maximal muscle strength were observed (p < 0.01) in resistance training groups when compared to the control group, with no differences between training groups. No differences in body composition were observed. There were no adverse events or side-effects of the intervention.

Conclusions

12 weeks of intense resistance training improves delayed verbal memory irrespective of training design (i.e., high-load vs. moderate-load).

Trial registration

This study is registered at www.anzctr.org.au ACTRN12616000690459.

Is sport enough? Contribution of sport to overall moderate- to vigorous-intensity physical activity among adolescents

07-07-2019 – Harriet Koorts, Anna Timperio, Lauren Arundell, Kate Parker, Gavin Abbott, Jo Salmon

Journal Article

Objectives

This study examined the contribution of sports participation to overall moderate-to-vigorous physical activity (MVPA) among adolescents, and explored potential moderators.

Design

Cross-sectional observational study using survey and accelerometry data drawn from the NEighbourhood Activity in Youth (NEArb
Y) study.

Methods

Adolescents (n = 358) were recruited from secondary schools in Melbourne, Australia. Average min/day in MVPA was assessed using accelerometry. Participants self-reported sports participation (number of teams, type, frequency, and months of participation). Regression models determined the percent variance in MVPA explained by the sport variables, adjusted for wear time, age and sex, and accounting for clustering at the school level. Additional analyses tested if age, sex, body mass index (BMI), and socioeconomic status (SES) moderated relationships between sport variables and MVPA.

Results

Participants (mean 15.3 years, 59% female) spent a mean (SD) of 68.6 (27.4) min/day in MVPA and 50% reported participating in any sport. Those who participated in sport did so 3.4 times/week on average and accumulated 7 min/day of MVPA more than those who did no sport. For each additional sport participated in, on average, there were approximately 5 additional min/day of MVPA. The number and frequency of sports participation explained 3.2% and 3.8% of the variance in MVPA respectively. Participation in field hockey and gymnastics explained 2.2% and 3.6% of the variance in MVPA, respectively. There were no moderating effects.

Conclusions

Sport appears to make a very small contribution to adolescents’ average daily physical activity. Effectiveness of approaches to increasing youth population levels of physical activity via sports participation needs to be tested.

Validity of the Polar Team Pro Sensor for measuring speed and distance indoors

06-07-2019 – Jordan L. Fox, Cody J. O’Grady, Aaron T. Scanlan, Charli Sargent, Robert Stanton

Journal Article

Objectives

To assess the validity of the Polar Team Pro Sensor for measuring speed and distance indoors during continuous locomotive and change-of-direction tasks at low, medium, and high intensities.

Design

Descriptive validation study.

Methods

26 recreationally-active participants (age: 32.2 ± 11.0 yr; stature: 173.3 ± 9.9 cm; body mass: 74.2 ± 16.2 kg) completed three trials of low- (walking speed), medium- (jogging speed), and high-intensity (maximal sprinting speed) continuous locomotive and change-of-direction tasks. Participants wore back- and chest-mounted sensors to determine mean speed and total distance covered. One-way analysis of variance, t-tests, Pearson’s Product moment correlation, and Bland–Altman plots were utilised to compare the speed and distance measured with the back- and chest-mounted sensors to reference measures (measured distance of the court via a trundle wheel and speed derived from measured distance and electronic timing lights).

Results

Speed and distance measured using the back- and chest-mounted sensors showed wide limits of agreement, which increased at high intensities for speed. The sensors typically underestimated speed and distance by as much as 2.76 km h−1 and 32.6 m, and overestimated speed and distance by as much as 4.52 km h−1 and 59.6 m across tasks and intensities compared to reference measures (168.45 and 40.00 m).

Conclusions

There was low agreement between both back- and chest-mounted sensors and the reference devices for measuring speed and distance indoors. Practitioners should understand the limitations and potential for error when using the Polar Team Pro Sensors indoors to measure speed and distance during continuous locomotive and change-of-direction tasks.

Dietary intakes of professional Australian football league women’s (AFLW) athletes during a preseason training week

06-07-2019 – Sarah L. Jenner, Brooke L. Devlin, Adrienne K. Forsyth, Regina Belski

Journal Article

Objectives

In 2016 the Australian football league introduced the first women’s league, integrating part-time female athletes into the professional sporting environment. This study aims to assess the dietary intakes of professional Australian football league women’s (AFLW) athletes to highlight key focus areas for nutrition and additionally provide nutrition recommendations for dietitians working with these athletes.

Design

Cross-sectional study.

Methods

Dietary intake data was collected from 23 players from the same club competing in the Australian football league women’s, during a preseason week. Dietary intakes were assessed using three day estimated food records.

Results

Majority of athletes did not meet recommendations for carbohydrate (96%, n = 22), iron (87%, n = 20) and calcium (61%, n = 14). In comparison, majority of athletes met protein (74%, n = 17) and fat (78%, n = 18) recommendations. No significant difference was found in energy intake on main training, light training and recovery days (p > 0.05). Energy and carbohydrate intakes reported by AFLW athletes (1884 ± 457 kcal day−1 and 2.7 ± 0.7 g kg−1 day−1) were consistent with values reported in previous studies that included professional female athletes.

Conclusions

This research highlights that further exploration of the factors that influence dietary intake is required to support athletes to meet energy and carbohydrate recommendations required for desired training and performance outcomes.

Snowsport trauma and safety: Understanding and reducing the likelihood of injury in snowsports

30-06-2019 – Irving S. Scher, Jeremy Witchalls, Richard M. Greenwald, Nicola Petrone

Editorial

Tattoos do not affect exercise-induced localised sweat rate or sodium concentration

27-06-2019 – Ethan Rogers, Christopher Irwin, Danielle McCartney, Gregory R. Cox, Ben Desbrow

Journal Article

Objectives

Skin tattoos have been shown to reduce localised sweat rate and increase sweat sodium concentration (Na+) when sweating is artificially stimulated. This study investigated whether similar responses are observed with exercise-induced sweating.

Design

Unblinded, within-participant control, single trial.

Methods

Twenty-two healthy individuals (25.1 ± 4.8 y (Mean ± SD), 14 males) with a unilateral tattoo ≥11.4 cm2 in size, ≥2 months in age, and shaded ≥50% participated in this investigation. Participants undertook 20 min of intermittent cycling (4 × 5 min intervals) on a stationary ergometer in a controlled environment (24.6 ± 1.1 °C; 64 ± 6% RH). Resultant sweat was collected into absorbent patches applied at two pairs of contralateral skin sites (pair 1: Tattoo vs. Non-Tattoo; pair 2: Control 1 vs. Control 2 (both non-tattooed)), for determination of sweat rate and sweat Na+. Paired samples t-tests were used to determine differences between contralateral sites.

Results

Tattoo vs. Non-Tattoo: Neither sweat rate (Mean ± SD: 0.92 ± 0.37 vs. 0.94 ± 0.43 mg·cm−2·min−1, respectively; p = 0.693) nor sweat Na+ (Median(IQR): 37(32–52) vs. 37(31–45) m
M·L−1, respectively; p = 0.827) differed. Control 1 vs. Control 2: Neither sweat rate (Mean±SD: 1.19 ± 0.53 vs. 1.19 ± 0.53 mg·cm−2·min−1, respectively; p = 0.917) nor sweat Na+ (Median(IQR): 29(26–41) vs. 31(25–43) m
M·L−1, respectively; p = 0.147) differed. The non-significant differences for sweat rate and Na+ between Tattoo vs. Non-Tattoo were inside the range of the within participant variability (sweat rate CVi = 5.4%; sweat Na+ CVi = 4.4%).

Conclusions

Skin tattoos do not appear to alter the rate or Na+ of exercise-induced sweating. The influence of skin tattoos on localised sweat responses may have previously been over-estimated.

Exacerbated heat strain during consecutive days of repeated exercise sessions in heat

27-06-2019 – Riana R. Pryor, J. Luke Pryor, Lesley W. Vandermark, Elizabeth L. Adams, Rachel M. Brodeur, Lawrence E. Armstrong, Elaine C. Lee, Carl M. Maresh, Jeffrey M. Anderson, Douglas J. Casa

Journal Article

Objectives

An exercise session in a hot environment may increase thermal strain during subsequent exercise sessions on the same and consecutive days. Therefore, this study was conducted to determine lasting physiological strain from moderate-high intensity, intermittent exercise in heat on subsequent exercise.

Design

Repeated measures laboratory study.

Methods

Seventeen healthy, recreationally active men (age: 22 ± 3 y, maximal oxygen consumption: 54.6 ± 5.3 m
L kg−1 min−1) underwent two intermittent moderate-high intensity aerobic exercise sessions separated by 2 h of rest one day, followed by one session 24 h later in a 40 °C, 40% relative humidity environment. Heart rate, rectal temperature, heat stress perception, and environmental symptoms were assessed.

Results

100%, 35%, and 71% of participants completed the full exercise protocol during the first exercise session, second exercise session, and the following day, respectively. Exercising heart rate and rectal temperature were greater during the second exercise session (189 ± 11 bpm, 38.80 ± 0.47 °C) than the first identical exercise session (180 ± 17 bpm, p = 0.004; 38.41 ± 0.52 °C, p = 0.001), respectively. Immediate post-exercise heart rate, rectal temperature, thirst, thermal sensation, fatigue, and perceived exertion were similar among exercise sessions despite a shorter exercise duration during the second exercise session (93 ± 27 min, p = 0.001) and the following day (113 ± 12 min, p = 0.032) than the first exercise session (120 ± 0 min).

Conclusions

Moderate-high-intensity intermittent exercise in the heat resulted in greater heat strain during a second exercise session the same day, and exercise the subsequent day.

Epidemiology of elite sprint kayak injuries: A 3-year prospective study

27-06-2019 – Liam A. Toohey, Michael K. Drew, Nicola Bullock, Britt Caling, Lauren V. Fortington, Caroline F. Finch, Jill L. Cook

Journal Article

Objectives

To analyse the characteristics of injuries sustained by elite sprint kayak athletes, to investigate relationships between initial and subsequent injuries, and to examine injury differences between male and female athletes.

Design

Descriptive epidemiology study.

Methods

Data from 63 athletes (37 male, 26 female) of the Australian national sprint kayak squad were prospectively collected over three continuous years (September 2014-August 2017). All medical attention injuries were recorded irrespective of time-loss and modality of training. Descriptive analyses were performed, and frequency comparisons across genders assessed with chi squared tests.

Results

Forty-nine athletes (78%) sustained 146 injuries (median = 2, interquartile range = 1–4, range = 0–12). Most injuries were to the upper limb (48%), with the shoulder being the most common body site injured (27%). Thirty-one athletes (49%) sustained at least one subsequent injury, equating to 97 subsequent injuries. The majority (68%) of subsequent injuries occurred at a different site and nature to previous injuries. Male athletes were more likely to sustain an injury than remain injury free compared to female athletes (Chi2(1) = 6.75, p = 0.009), but there was no difference between males and females who thereafter sustained a subsequent injury (Chi2(1) = 0.84, p = 0.359).

Conclusions

Injury occurrence is common in sprint kayak, with many athletes experiencing more than one injury. Small variations in injury characteristics exist between male and female athletes in sprint kayak. This study identifies upper limb and trunk, and joint and muscle injuries as the most prevalent sprint kayak injuries, providing a focus for the development of future injury prevention strategies.

Functional differences in softball pitchers with and without upper extremity pain

25-06-2019 – Gretchen D. Oliver, Gabrielle G. Gilmer, Kenzie B. Friesen, Hillary A. Plummer, Adam W. Anz, James R. Andrews

Journal Article

Objectives

Though pitchers often throw during multiple games in a day, there are currently no pitch count restrictions in softball. The accumulation of high pitch counts over time may contribute to the development of upper extremity pain. The purpose of our study was to examine functional characteristics of shoulder and hip range of motion (ROM), isometric strength (ISO), and ball speed in softball pitchers with and without upper extremity (UE) pain.

Design

Controlled laboratory design.

Methods

Fifty-three NCAA Division I softball pitchers (20.0 ± 1.4 years; 173.3 ± 8.3 cm; 80.9 ± 12.3 kg) participated and were divided into two groups: pain-free (n = 30) and pain in the UE (n = 23). Bilateral shoulder and hip external rotation (ER) and internal rotation (IR) ROM and ISO were measured prior to pitching to a catcher located 13.1 m (43 ft) away.

Results

Independent samples t-tests revealed significantly greater throwing side (TS) hip ER ROM (p = 0.012), TS hip IR ISO (p = 0.038), glove side (GS) hip ER ISO (p = 0.025), TS shoulder ER ISO (p = 0.002), GS shoulder IR (p = 0.006) and ER (p = 0.004) ISO in the pain free group versus the UE pain group.

Conclusions

Differences in shoulder and hip ROM and ISO exist between those who have upper extremity pain and those who do not. Therefore, findings suggest that both the upper and lower extremities should be considered when treating softball pitchers with UE pain.

Additional evidence supports association of common genetic variants in MMP3 and TIMP2 with increased risk of chronic Achilles tendinopathy susceptibility

19-06-2019 – Guanghua Nie, Xiaodong Wen, Xiaojun Liang, Hongmou Zhao, Yi Li, Jun Lu

Journal Article

Objectives

To systematically evaluate the effects of matrix metalloproteinase-3 (MMP3) and tissue inhibitor of metalloproteinase-2 (TIMP2) on chronic Achilles tendinopathy (AT) susceptibility. Chronic AT is one of the most prevalent and severe injuries in athletes. Early studies suggested that tendon extracellular matrix (ECM) may be involved in the pathogenesis of chronic AT. MMP3 is an important member of the MMP family and is important to ECM integrity. In addition, tissue inhibitor of metalloproteinase-2 (TIMP2) can indirectly limit the activity of MMP3 activity.

Design

Case-control genetic association study.

Methods

A total of 1084 chronic AT patients and 2188 controls with Chinese Han ancestry were recruited. Twenty-one SNPs, 4 mapped to MMP3 and 17 mapped to TIMP2, were selected and genotyped. Genetic association analyses and e
QTL analyses were performed. In addition, we also examined the potential effects of epistasis using a case-only study design.

Results

Two SNPs, rs679620 (OR = 0.82, P = 0.0006, MMP3) and rs4789932 (OR = 1.2, P = 0.0002, TIMP2) were identified to be significantly associated with chronic AT risk. No significant results were obtained from epistasis analyses. SNP rs4789932 was identified to be strongly associated with the gene expression level of TIMP2 in two types of human tissues: atrial appendage (P = 0.0003) and tibial artery (P = 0.0009).

Conclusions

We have identified genetic polymorphisms in MMP3 and TIMP2 to be significantly associated with chronic AT risk. Further e
QTL analyses indicated that SNP rs4789932 of TIMP2 was related to the gene expression levels of TIMP2. These results suggest important roles for MMP3 and TIMP2 in the pathophysiology of chronic AT.

The importance of nicotine use among winter sports athletes especially in skiers

17-06-2019 – Thomas Zandonai, Cristiano Chiamulera

Letter

A helmetless-tackling intervention in American football for decreasing head impact exposure: A randomized controlled trial

18-06-2019 – Erik E. Swartz, Jay L. Myers, Summer B. Cook, Kevin M. Guskiewicz, Michael S. Ferrara, Robert C. Cantu, Hong Chang, Steven P. Broglio

Journal Article

Objectives

To evaluate a behavioral intervention to reduce head impact exposure in youth playing American football.

Design

Nested randomized controlled trial.

Methods

Participants, ages 14–17 years, wore head impact sensors (SIM-G™) during two seasons of play. Those randomized to the intervention group underwent weekly tackling/blocking drills performed without helmets (Wo
H) and shoulder pads while the control group trained as normal, matching frequency and duration. Research personnel provided daily oversight to maintain fidelity. Head impact frequency (≥10 g) per athlete exposure (Imp
AE) was analyzed over time (two 11-week seasons) using mixed effect models or ANCOVA. Secondary outcomes included exposure-type (training, game) and participation level (entry-level versus upper-level secondary education).

Results

One-hundred fifteen participants (59 Wo
H, 56 control) met compliance criteria, contributing 47,382 head impacts and 10,751 athlete exposures for analysis. Wo
H had fewer Imp
AE during games compared to control participants at weeks 4 (p = 0.0001 season 1, p = 0.0005 season 2) and 7 (p = 0.0001 both seasons). Upper-level Wo
H participants had less Imp
AE during games than their matched controls at weeks 4 (p = 0.017 and p = 0.026) and 7 (p = 0.037 and p = 0.014) in both seasons, respectively. Upper-level Wo
H also had fewer Imp
AE during training at week 7 (p = 0.015) in season one.

Conclusions

Tackling and blocking drills performed without a helmet during training reduced the frequency of head impacts during play, especially during games. However, these differences disappeared by the end of the season. Future research should explore the frequency of behavioral intervention and a dose-response relationship considering years of player experience.

Trial registration

Clinical
Trials.gov # NCT02519478.

Feasibility of using a novel instrumented human head surrogate to measure helmet, head and brain kinematics and intracranial pressure during multidirectional impact tests

06-07-2019 – Nicola Petrone, Gianluca Candiotto, Edoardo Marzella, Federico Uriati, Giovanni Carraro, Mikael Bäckström, Andrey Koptyug

Journal Article

Objectives

Aim of the work is to present the feasibility of using an Instrumented Human Head Surrogate (IHHS-1) during multidirectional impacts while wearing a modern ski helmet. The IHHS-1 is intended to provide reliable and repeatable data for the experimental validation of FE models and for the experimental evaluation of modern helmets designed to enhance the degree of protection against multidirectional impacts.

Design

The new IHHS-1 includes 9 triaxial MEMS accelerometers embedded in a silicone rubber brain, independently molded and presenting lobes separation and cerebellum, placed into an ABS skull filled with surrogate cerebrospinal fluid. A triaxial MEMS gyroscope is placed at the brain center of mass. Intracranial pressure can be detected by eight pressure sensors applied to the skull internal surface along a transversal plane located at the brain center of mass and two at the apex. Additional MEMS sensors positioned over the skull and the helmet allow comparison between outer and inner structure kinematics and surrogate CSF pressure behavior.

Methods

The IHHS-1 was mounted through a Hybrid III neck on a force platform and impacted with a striker connected to a pendulum tower, with the impact energies reaching 24J. Impact locations were aligned with the brain center of mass and located in the back (sagittal axis), right (90° from sagittal axis), back/right (45°), and front right (135°) locations. Following dynamic data were collected: values of the linear accelerations and angular velocities of the brain, skull and helmet; intracranial pressures inside the skull.

Results

Despite the relatively low intensity of impacts (HIC at skull max value 46), the skull rotational actions reached BrIC values of 0.33 and angular accelerations of 5216 rad/s2, whereas brain angular acceleration resulted between 1,44 and 2,1 times lower with similar values of BrIC.

Conclusions

The IHHS-1 is a physical head surrogate that can produce repeatable data for the interpretation of inner structures behavior during multidirectional impacts with or without helmets of different characteristics.

The effects of relative cycling intensity on saddle pressure indexes

09-06-2019 – Wendy Holliday, Julia Fisher, Jeroen Swart

Journal Article

Objectives

To compare pressure load and distribution in various saddle zones through a range of workloads in order to provide clinicians and bike fitters with a better understanding of how to optimise saddle positioning.

Design

Experimental, quantitative study.

Methods

Saddle pressure of seventeen male well-trained cyclists was recorded at 60, 80 and 90% of maximal heart rate, based on data collected during a peak power output test.

Results

Loaded area increased significantly and progressively with increased workload while mean pressure did not change significantly. Point of load indexes in longitudinal and transverse planes both increased significantly and progressively with increases in workload. Distribution of load did not change with intensity.

Conclusions

Saddle pressure mapping should ideally be performed at an intensity similar to that which the cyclist will encounter during the majority of their training and racing. Comparative measurements of saddle pressures should also standardise workload intensity to ensure reliability of these measurements.

Coach knowledge in talent identification: A systematic review and meta-synthesis

28-05-2019 – Alexandra H. Roberts, Daniel A. Greenwood, Mandy Stanley, Clare Humberstone, Fiona Iredale, Annette Raynor

Journal Article, Review

Objectives

Talent identification traditionally relies on the knowledge and perceptions of expert coaches to identify and predict potential future elite athletes. Experiential coach knowledge is a valuable source of information to guide research in this ill-defined and under-researched area. This review aims to synthesize current empirical understanding of coach knowledge as it relates to decision making in talent identification.

Design

This systematic review and meta-synthesis used the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify relevant literature.

Methods

Eligible studies were critically appraised for quality, and key findings from the 14 studies were integrated to allow for thematic analysis.

Results

The meta-synthesis revealed the key theme of ‘instinct’ as the primary contributor to coach decisions during talent identification. Subordinate themes informing coach instinct were ‘drive and ambition’, ‘game intelligence’ and ‘physical and technical skills’.

Conclusions

Coaches appear to make decisions about talent based on their tacit knowledge or instinct. Understanding how coaches develop these instinctual ‘feelings’ may guide future research into talent identification and enhance our understanding of how experiential coach knowledge is developed and utilised in the daily training environment.

Incidence and impact of time loss and non-time-loss shoulder injury in elite South African cricketers: A one-season, prospective cohort study

04-06-2019 – Megan Dutton, Nicholas Tam, Janine Gray

Journal Article

Objectives

To determine the incidence, prevalence and impact of shoulder injury in elite South African cricketers.

Design

Prospective longitudinal cohort study.

Methods

One hundred and six senior national/franchise cricketers completed a pre-season Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) score. All injuries sustained during the 2016/2017 season were captured on an injury reporting system. Injuries were verified by the respective squad physiotherapist at the end of the season and post-season KJOC score was obtained from all the players.

Results

Eighteen percent (95% CI: 11–25%) of cricketers sustained a shoulder injury, at a rate of 0.19 injuries per player per year. Annual injury prevalence was 1.1%. Shoulder injury occurred primarily while throwing (58%). Fielding performance was maintained by adapting throwing technique (58%) or fielding position (21%). Thirty-two percent of shoulder injuries resulted in time lost to matches and/or training. A history of shoulder injury increased the risk of sustaining another injury by 1.91 times (95% CI: 1.73–2.15). Irrespective of injury, cricketers demonstrated consistently low pre- (78.5 ± 15.6) and post-season (81.2 ± 17.1) KJOC scores. Pre-season KJOC scores were significantly lower (r2 = 0.106, p = 0.001) in those cricketers with a history of shoulder injury. Cricketers who sustained a seasonal shoulder injury had significantly lower (r2 = 0.112, p < 0.001) post-season KJOC scores, indicating persistent shoulder pain or dysfunction.

Conclusion

This is the first study to report both time- and non-time-loss shoulder injury in elite South African cricketers. All non-time-loss shoulder injuries compromised primary skill, while some resulted in changes to throwing technique and fielding position. Thus shoulder injury, whether it results in time loss or not, potentially impacts match performance.

The Exercise and Sports Science Australia position statement: Exercise medicine in cancer management

07-07-2019 – Sandra C. Hayes, Robert U. Newton, Rosalind R. Spence, Daniel A. Galvão

Journal Article, Review

Objectives

Since Exercise and Sports Science Australia (ESSA) first published its position statement on exercise guidelines for people with cancer, there has been exponential growth in research evaluating the role of exercise pre-, during and post-cancer treatment.

Design and Methods

The purpose of this report is to use the current scientific evidence, alongside clinical experience and exercise science principles to update ESSA’s position statement on cancer-specific exercise prescription.

Results

Reported in this position statement is a summary of the benefits accrued through exercise following a cancer diagnosis and the strengths and limitations of this evidence-base. An exercise prescription framework is then proposed to enable the application of cancer-specific considerations for individualisation, specificity, safety, feasibility and progression of exercise for all patients. Additional specific exercise prescription considerations are provided for the presence of haematological, musculoskeletal, systemic, cardiovascular, lymphatic, gastrointestinal, genitourinary and neurological disease- and treatment-related concerns, as well as presence of co-morbid chronic disease. Further, we also identify and discuss cancer-specific pragmatic issues and barriers requiring consideration for exercise prescription.

Conclusions

While for the majority, multimodal, moderate to high intensity exercise will be appropriate, there is no set prescription and total weekly dosage that would be considered evidence-based for all cancer patients. Targeted exercise prescription, which includes the provision of behaviour change advice and support, is needed to ensure greatest benefit (as defined by the patient) in the short and longer term, with low risk of harm.

The relationship of team and individual athlete performances on match quarter outcome in elite women’s Australian Rules football

28-05-2019 – Emily E. Cust, Alice J. Sweeting, Kevin Ball, Hamish Anderson, Sam Robertson

Journal Article

Objectives

To evaluate the relationships between the athlete distribution of team performance indicators and quarter outcome in elite women’s Australian Rules football matches.

Design

Retrospective longitudinal cohort analysis.

Methods

Thirteen performance indicators were obtained from 56 matches across the 2017 and 2018 Australian Football League Women’s (AFLW) seasons. Absolute and relative values of 13 performance indicators were obtained for each athlete, in each quarter of all matches. Eleven features were further extracted for each performance indicator, resulting in a total of 169 features. Generalised estimating equations (GEE) and regression decision trees were run across the different feature sets and dependent variables, resulting in 22 separate models.

Results

The GEE algorithm produced slightly lower mean absolute errors across all dependent variables and feature sets comparative to the regression decision tree models. Quarter outcome was more accurately explained when considered as total points scored comparative to quarter score margin. Team differential and the 75th percentile of individual athlete Inside 50s were the strongest features included in the models.

Conclusions

Modelling performance statistics by quarter outcomes provides specific practical information for in-game tactics and coaching in relation to athlete performances each quarter. Within the current elite women’s Australian Rules football competition, key high performing individual athletes’ skilled performances within matches contribute more to success rather than a collective team effort.

Vascular and oxygenation responses of local ischemia and systemic hypoxia during arm cycling repeated sprints

21-05-2019 – Sarah J. Willis, Arthur Peyrard, Thomas Rupp, Fabio Borrani, Grégoire P. Millet

Journal Article

Objectives

The purpose of this study was to investigate the acute vascular and oxygenation responses to repeated sprint exercise during arm cycling with either blood flow restriction (BFR) or systemic hypoxia alone or in combination.

Design

The study design was a single-blinded repeated-measures assessment of four conditions with two levels of normobaric hypoxia (400 m and 3800 m) and two levels of BFR (0% and 45% of total occlusion).

Methods

Sixteen active participants (eleven men and five women; mean ± SD; 26.4 ± 4.0 years old; 73.8 ± 9.8 kg; 1.79 ± 0.07 m) completed 5 sessions (1 familiarization, 4 conditions). During each test visit, participants performed a repeated sprint arm cycling test to exhaustion (10 s maximal sprints with 20 s recovery until exhaustion) to measure power output, metabolic equivalents, blood flow, as well as oxygenation (near-infrared spectroscopy) of the biceps brachii muscle tissue.

Results

Repeated sprint performance was decreased with both BFR and systemic hypoxia conditions. Greater changes between minimum-maximum of sprints in total hemoglobin concentration (Δt
Hb) were demonstrated with BFR (400 m, 45% and 3800 m, 45%) than without (400 m, 0% and 3800 m, 0%) (p < 0.001 for both). Additionally, delta tissue saturation index (ΔTSI) decreased more with both BFR conditions than without (p < 0.001 for both). The absolute maximum TSI was progressively reduced with both BFR and systemic hypoxia (p < 0.001).

Conclusions

By combining high-intensity, repeated sprint exercise with BFR and/or systemic hypoxia, there is a robust stimulus detected by increased changes in blood perfusion placed on specific vascular mechanisms, which were more prominent in BFR conditions.

Short- and middle-term high-altitude exposure does not affect visual acuity and contrast sensitivity of healthy young people

04-06-2019 – Till Krusche, Gernot Jendrusch, Petra Platen

Journal Article

Objective

Visual acuity and contrast sensitivity are crucial for optimal performance and safe sport activity. From a practical sport-specific perspective, visual performance is obligatory for orientation and movement control in mountainous areas. The purpose of this study was to analyze the effect of hypobaric hypoxic conditions on visual acuity and contrast sensitivity of short-term and middle-term acclimatized healthy young people.

Design

This study used a repeated-measure design with ten eye-healthy and physically active students representing different types of sports.

Methods

With the help of a computer-based Landolt C and a Sine Wave Contrast test, visual performance was investigated similar before (156 m), during a nine-day high-altitude sojourn (sleeping level: 890–4640 m), and three months later (156 m). All tests were performed under standardized illumination conditions. Additionally, morning blood oxygen saturation, hematocrits, hemoglobin, body mass, and self-reported symptoms of acute mountain sickness criteria were determined.

Results

Whole blood oxygen saturation declined during altitude exposure. The analysis of central visual performance at altitude showed no effect of hypobaric hypoxia.

Conclusion

Our data suggest that activity in a hypobaric hypoxia condition at moderate to high altitude levels of up to 4600 m does not affect visual acuity and contrast sensitivity of acclimatized healthy young people. However, in contrast to previous studies that outlined acutely impaired central visual performance with respect to hypoxia, we suggest that acclimatization might induce adaptation of visual perception performance and therefore reduce the risk of accidents resulting from partial loss of visual performance at altitude.

The use of medication and alcohol in recreational downhill skiers: Results of a survey including 816 subjects in Tyrol

28-05-2019 – Verena Menz, Marc Philippe, Elena Pocecco, Gerhard Ruedl, Tomas Woldrich, Renate Sommersacher, Martin Burtscher

Journal Article

Objective

The aim of this study was to collect data on the medication and alcohol use in recreational downhill skiers.

Design

Cross-sectional study.

Methods

The study was conducted during the 2014 winter season in different ski resorts in Tyrol, Austria. Participants were asked to complete a brief survey including questions about basic anthropometric data (age, stature, weight) the use of medication (yes/no) and alcohol intake on the skiing day or the day before (yes/no).

Results

In total, 816 persons with an age between 6–87 years were surveyed. In general, 22% of the male and 20% of the female recreational downhill skiers reported the use of medication. In the age group >40 years, half of the respondents were taking medication on a regular basis. 30% of males and 16% of females reported to consume alcohol on the skiing day whereas more than 50% drank alcohol on the evening before skiing the next day. 63% of those under medication concomitantly consumed alcohol.

Conclusions

The findings confirm a high prevalence of medication use and alcohol consumption in recreational downhill skiers. Even more importantly, 63% of skiers under medication concomitantly consumed alcohol. Considering the fact that only a small amount of alcohol can already affect motor and cognitive skills, it may be strongly assumed that the risk for skiing injuries is increased with alcohol consumption. Side effects of simultaneous intake of drugs and alcohol may include hypotension, vertigo and collapse which are thought to be associated with increased risks of skiing falls and injuries.

Passive range of motion of the hips and shoulders and their relationship with ball spin rate in elite finger spin bowlers

20-05-2019 – Liam Sanders, Steve McCaig, Paul J. Felton, Mark A. King

Journal Article

Objectives

Investigate rotational passive range of motion of the hips and shoulders for elite finger spin bowlers and their relationship with spin rate.

Design

Correlational.

Methods

Spin rates and twelve rotational range of motion measurements for the hips and shoulders were collected for sixteen elite male finger spin bowlers. Side to side differences in the rotational range of motion measurements were assessed using paired t-tests. Stepwise linear regression and Pearson product moment correlations were used to identify which range of motion measurements were linked to spin rate.

Results

Side to side differences were found with more external rotation (p = 0.039) and less internal rotation (p = 0.089) in the bowling shoulder, and more internal rotation in the front hip (p = 0.041). Total arc of rotation of the front hip was found to be the best predictor of spin rate (r = 0.552, p =  0.027), explaining 26% of the observed variance. Internal rotation of the rear hip (r = 0.466, p =  0.059) and the bowling shoulder (r = 0.476, p =  0.063) were also associated with spin rate.

Conclusions

The technique and performance of elite finger spin bowlers may be limited by the passive range of motion of their hips and shoulders. The observed side to side differences may indicate that due to the repetitive nature of finger spin bowling adaptive changes in the rotational range of motion of the hip and shoulder occur.