Journal of Science and Medicine in Sport

Journal of Science and Medicine in Sport

Do tattoos impair sweating?

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

Editorial

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

Journal Article, Published Erratum

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

17-06-2019 – Thomas Zandonai, Cristiano Chiamulera

Letter

Benefit of exercise in concussion rehabilitation

10-09-2019 – Gordon S. Waddington

Editorial

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.

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.

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.

Biological maturation and match running performance: A national football (soccer) federation perspective

06-05-2019 – Ric Lovell, Job Fransen, Rhearne Ryan, Tim Massard, Rebecca Cross, Tahleya Eggers, Rob Duffield

Journal Article

Objectives

To examine the influence of maturation and its interaction with playing position upon physical match performances in U15 footballers from a national federation.

Design

Observational study.

Methods

278 male outfield players competing in a national tournament were assessed for somatic maturity and match physical performances according to playing position. Stature, sitting height, and body mass were measured and entered into an algorithm to estimate the age at peak height velocity (APHV). Players match movements were recorded by Global Positioning System devices (10 Hz), to determine peak speed, and total- (TD), low-speed running (LSR; ≤13.0 km h−1), high-speed running (HSR; 13.1–16.0 km h−1), very high-speed running (VHSR; 16.1–20.0 km h−1) and sprint distances (SPR; >20.0 km h−1) expressed relative to match exposure (m min−1).

Results

Linear-mixed models using log transformed response variables revealed a significant contribution of estimated APHV upon TD (1.01; 95% CI: 0.99–1.02 m·min−1; p < 0.001), HSR (1.05; 95% CI: 0.98–1.13 m min−1; p < 0.001) and VHSR (1.07; 95% CI: 1.00–1.14 m min−1; p = 0.047). An increase by one year in APHV was associated with an increase of 0.6, 5.4 and 6.9% in TD, HSR and VHSR respectively. No effects of APHV were observed for LSR, SPR, and peak speed. Further, no APHV effects were observed relative to players’ field position.

Conclusions

Later maturing players covered substantially more higher-intensity (HSR and VHSR) running in matches, irrespective of playing position. The greater match intensity of later maturing players may inform talent identification and athletic development processes within a national federation.

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.

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.

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.

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.

Daily steps and diet, but not sleep, are related to mortality in older Australians

17-10-2019 – Stina Oftedal, Elizabeth G. Holliday, John Attia, Wendy J. Brown, Clare E. Collins, Benjamin Ewald, Nicholas Glozier, Mark McEvoy, Philip J. Morgan, Ronald C. Plotnikoff, Emmanuel Stamatakis, Corneel Vandelanotte, Mitch J. Duncan

Journal Article

Objectives

Supporting healthy ageing is a key priority worldwide. Physical activity, diet quality and sleep are all associated with health outcomes, but few studies have explored their independent associations with all-cause mortality in an older population in the same model. The study aim was to examine associations between step-count, self-reported diet quality, restless sleep, and all-cause mortality in adults aged 55–85 years.

Design

A prospective cohort study of adults in Newcastle, New South Wales, Australia.

Method

Data were from 1697 participants (49.3% women; baseline mean age 65.4 ± 7.1 years). Daily steps (measured by pedometer), diet quality (from a modified Australian Recommended Food Score), and frequency of restless sleep (by self-report) were assessed in relation to all-cause mortality using Cox proportional hazard regression with adjustment for sex, age, household income and smoking. Baseline data were collected between January 2005 and April 2008, and last follow-up was in March 2017 (median follow-up 9.6 years).

Results

Higher step count (HR: 0.93, 95%CI: 0.88–0.98 per 1000-step increment) and higher diet quality (HR: 0.86, 95%CI: 0.74–0.99 per 8-point increment in diet quality score) were associated with reduced mortality risk. Restless sleep for ≥3 nights/week was not associated with mortality risk (HR: 1.03, 95%CI: 0.78–1.39). Sensitivity analyses, adjusting for chronic disease and excluding deaths <1 year after baseline, did not change these estimates.

Conclusions

Increased daily steps and consumption of a greater variety of nutrient-dense foods every week would result in substantial health benefits for older people. Future research should include a greater variety of sleep measures.

Y balance test: Are we doing it right?

12-10-2019 – Andrea Fusco, Giuseppe Francesco Giancotti, Philip X. Fuchs, Herbert Wagner, Rubens A. da Silva, Cristina Cortis

Journal Article

Objectives

The multifaceted characteristic and task-specificity of postural control clearly reflects the need of knowing which factors could influence the balance measures in order to provide reliable and unbiased information. Therefore, this study aimed to investigate the effects of selected anthropometric characteristics, sex, lower limb’s strength and dominance on the Y balance test (YBT).

Design

Descriptive laboratory study.

Methods

Forty-two young adults performed the YBT. The raw and normalized reach distances values were recorded. ANOVA was used to examine differences between sex and limb dominance, whereas multiple linear regression models were built to identify variables associated with better postural control.

Results

No significant sex differences were observed, except for the normalized anterior direction (p = 0.0324). No significant differences between limbs emerged. Regression models significantly explained between 8–49% of the variance. Trunk length, strength, and the interaction between sex with strength were the major predictors of the raw measures. Unexpectedly, lower limb length explained only 0.08% of the raw anterior direction variance. Strength and its interaction with sex were positively associated with normalized measures. Surprisingly, the relative lower limb length variable was negatively associated with the normalized measures. Each % point increase in relative lower limb length was associated with a decrease in normalized performance ranging from 1.73 to 4.91%.

Conclusions

Anthropometric characteristics, sex and lower limb strength differently influenced the YBT measures, regardless of limb dominance. Consequently, these variables should be controlled to limit the variability for an accurate evaluation of postural balance, especially if different YBT measures are used.

Bone geometry and lower extremity bone stress injuries in male runners

09-10-2019 – Kristin L. Popp, Adam C. Frye, Steven D. Stovitz, Julie M. Hughes

Journal Article

Bone stress injuries (BSI) are common among distance runners and research investigations examining risk factors for BSI among men are limited. Therefore, investigations are needed to determine if men with a history of BSI have skeletal properties that may heighten BSI incidence.

Objectives

To analyze differences in bone density, bone geometry, and estimates of bone strength in male runners with and without a BSI history.

Design

Cross-sectional.

Methods

We recruited 36 male distance runners ages 18–41 for this study. We used peripheral quantitative computed tomography (p
QCT) to assess volumetric bone mineral density (v
BMD, mg/mm3), bone geometry (total and cortical bone area, mm2), tibia robustness (total area/tibia length, mm) and estimates of bone strength (section modulus and polar strength-strain index, mm3) at 5 tibial sites.

Results

After adjusting for age, the BSI group had more slender tibias (9%), lower stress strain indices (−16%), lower section moduli (−17%) and smaller total cross-sectional (−11%) and cortical areas (−12%) at the 66% site of the tibia compared with controls (P < 0.05 for all). Similar differences were found at all other measurement sites. After adjusting for body size, differences in bone outcomes remained significant at the 66% site.

Conclusions

These results indicate that men with a history of BSI have lower estimated bending strength compared to controls because of narrower tibias. However, differences are largely attenuated in the distal ½ of the tibia after adjusting for body size. Thus, smaller tibia size, particularly at the mid-diaphysis, may be an important indicator for BSI incidence.

Using cooperative networks to analyse behaviour in professional Australian Football

05-10-2019 – William B. Sheehan, Rhys Tribolet, Mark L. Watsford, Andrew R. Novak, Michael J. Rennie, Job Fransen

Journal Article

Objectives

Reducing the dimensionality of commonly reported complex network characteristics obtained from Australian Football League (AFL) games to facilitate their practical use and interpretability.

Design

Retrospective longitudinal design where individual players’ interactions, determined through the distribution and receipt of kicks and handballs, during official AFL games were collected over three seasons.

Methods

A principal component analysis was used to reduce the number of characteristics related to the cooperative network analysis.

Results

The principal component analysis derived two individual-based principal components pertaining to in- and out-degree importance and three team-based principal components related to connectedness and in- and out-degree centralisation.

Conclusions

This study is the first to provide a simplified, novel method for analysing complex network structures in an Australian Football context with both the team- and individual-derived metrics revealing useful information for coaches and practitioners. This may consequently guide opposition analysis, training implementation, player performance ratings and player selection.

Prevalence and application of priming exercise in high performance sport

09-10-2019 – Peter W. Harrison, Lachlan P. James, Mike R. McGuigan, David G. Jenkins, Vincent G. Kelly

Journal Article

Objectives

Recent research has revealed that low volume resistance ‘priming’ exercise may improve neuromuscular performance when completed within 48 h before competition. The aim of this study was to investigate the current prevalence and application of this strategy by practitioners in sport.

Design

This study surveyed practitioners who were currently programming and/or prescribing resistance training programs for high performance athletes.

Methods

Sixty-nine practitioners completed the online survey relating to their perceptions of resistance priming exercise strategies and the training methods prescribed in the days prior to competition.

Results

Fifty-one percent of respondents currently prescribed priming exercise. Of the practitioners who prescribed this strategy, most respondents (59%) prescribed this session within 8 h of competition. Sessions typically included 2–3 upper body and lower body exercises (mean = 2.5 ± 0.7 and 2.1 ± 0.6 respectively), usually involving both loaded and unloaded activities. Large variations in exercise selection were reported, however, unloaded jumps (87%), loaded jumps (60%) and bench press (56%) were commonly prescribed. A low volume of sets (mean = 2.8 ± 0.9) and repetitions (mean = 3.8 ± 1.3) were used during these sessions. Lastly, various resistance loading strategies were prescribed, ranging from unloaded activities to heavy loaded exercises performed at ≥85% 1RM.

Conclusions

Priming exercise is currently prescribed by many practitioners to prepare athletes for competition. A wide range of priming exercise methods are used, despite limited evidence supporting these methods. Future research should examine the effects of the various priming methods which are currently applied in practice.

Pain perception and coping strategies influence early outcomes following knee surgery in athletes

30-09-2019 – Joshua S. Everhart, Aaron J. Chafitz, Kristie M. Harris, Steven E. Schiele, Charles F. Emery, David C. Flanigan

Journal Article

Objectives

To determine whether pain perceptions and coping strategies are predictive of the following outcomes after knee surgery in athletes: (1) return to similar level of sport, (2) improvement in symptoms, and (3) improvement in kinesiophobia.

Design

Prospective cohort study.

Methods

101 athletes (52 men, 49 women; mean age 32.7 years) at mean 12.1 months follow-up were included. Independent relationships between patient outcomes and pre-operative measures were determined: short form McGill Pain questionnaire (SF-MPQ), Pain Catastrophizing Scale (PCS), Pain Coping Measure (PCM), and the brief COPE subscales of acceptance, denial, positive reframing, and use of instrumental support. Adjustment was performed for length of follow-up, symptom duration, surgical history, age, activity level, and surgical procedure.

Results

Rate of return to similar level of sport was 73%; severe pain catastrophizers (PCS >36 points) had increased odds of not returning to similar level of sport (OR 11.3 CI 1.51, 236; p = 0.02) whereas COPE-use of instrumental support was protective (per point increase: 0.72 CI 0.54, 0.94; p = 0.02). Problem-focused coping positively correlated with improvement in IKDC-S scores (beta 0.032 SE 0.010; p = 0.001). Improvement in kinesiophobia after surgery was less likely with higher pre-operative perceived pain frequency (OR 0.23 CI 0.06, 0.71; p = 0.009) and higher COPE-denial scores (OR 0.43 CI 0.21, 0.88; p = 0.02).

Conclusions

Among athletes undergoing knee surgery, severe pain catastrophizing is negatively associated with return to similar level of sport. Instrumental support and problem-focused coping strategies are associated with improved outcomes. High preoperative pain scores are negatively associated with improvement in kinesiophobia after rehabilitation.

Harmful association of sprinting with muscle injury occurrence in professional soccer match-play: A two-season, league wide exploratory investigation from the Qatar Stars League

09-10-2019 – Warren Gregson, Valter Di Salvo, Matthew C. Varley, Mattia Modonutti, Andrea Belli, Karim Chamari, Matthew Weston, Lorenzo Lolli, Cristiano Eirale

Journal Article

Objectives

To investigate the impact of physical efforts performed in the period preceding activity as a potential risk factor of muscle injury during match-play within a sample of professional soccer players.

Design

Observational cohort study.

Methods

Match load (running >14.4–19.8 km/h, high-speed running >19.8–25.2 km/h, sprinting >25.2 km/h, leading and explosive sprint type) averaged in 1-min and 5-min periods prior to an event or non event for 29 professional outfield soccer players. Conditional logistic and Poisson regression models estimated the relationship between load and injury for a 2 within-subject standard deviation in match load or 1-action increment in the number of sprinting activities, respectively. Associations were deemed beneficial or harmful based on non-overlap of the 95% confidence intervals against thresholds of 0.90 and 1.11, respectively.

Results

An increment in sprinting distance +2-SDs = 11 m covered over a 1-min period (odds ratio OR: 1.22, 95%CI, 1.12 to 1.33) increased the odds of muscle injury.

Conclusions

Our study provides novel exploratory evidence that the volume of sprinting during competitive soccer match-play has a harmful association with muscle injury occurrence.

Distinct microbiome composition and metabolome exists across subgroups of elite Irish athletes

29-09-2019 – Ciara M. O’Donovan, Sharon M. Madigan, Isabel Garcia-Perez, Alan Rankin, Orla O’ Sullivan, Paul D. Cotter

Journal Article

Objectives

The gut microbiome has begun to be characterised in athlete groups, albeit, to date, only across a subset of sports. This study aimed to determine if the gut microbiome and metabolome differed across sports classification groups (SCGs) among elite Irish athletes, many of whom were participating in the 2016 Summer Olympics.

Methods

Faecal and urine samples were collected from 37 international level athletes. Faecal samples were prepared for shotgun metagenomic sequencing and faecal and urine samples underwent metabolomic profiling.

Results

Differences were observed in the composition and functional capacity of the gut microbiome of athletes across SCGs. The microbiomes of athletes participating in sports with a high dynamic component were the most distinct compositionally (greater differences in proportions of species), while those of athletes participating in sports with high dynamic and static components were the most functionally distinct (greater differences in functional potential). Additionally, both microbial (faecal) and human (urine) derived metabolites were found to vary between SCGs. In particular cis-aconitate, succinic acid and lactate, in urine samples, and creatinine, in faeces, were found to be significantly different between groups. These differences were evident despite the absence of significant differences in diet, as determined using food frequency questionnaires, which were translated into nutrient intake values using FETA.

Conclusions

Differences in the gut microbiome and metabolome between groups, in the absence of dietary changes, indicates a role for training load or type as a contributory factor. Further exploration of this hypothesis has the potential to benefit athletes, aspiring athletes and the general public.

External and internal workload demands of women’s twenty 20 cricket competition

26-09-2019 – Fabian Garcia-Byrne, Jonathan D. Buckley, Chris Bishop, Stephen Schwerdt, Jonathon Porter, David Bailey, Thomas P. Wycherley

Journal Article

Objective

To quantify the external and internal workloads of women’s Twenty–Twenty (T20) cricket and compare match demands between International, National and Youth level cricket players.

Design

A retrospective analysis of data collected form T20 matches played by Australian teams (International level, n = 3; National level, n = 12; Youth level, n = 4) during the 2016–17 Australian cricket season.

Method

Thirty-four women’s T20 cricket players playing for the Australian (International; n = 10), South Australian (National; n = 11) and South Australian Youth (Youth; n = 13) teams participated in the study. Global Positioning System devices captured player movements during matches including distance (metres m), Player
Load (arbitrary units AU), and distance covered at different velocities. A smartphone app was used to capture the sessional rating of perceived exertion (s
RPE) for each match Multilevel mixed-effects linear regression was performed for each outcome to evaluate the differences between player level (International, National and Youth). Statistical significance was set at p < 0.05.

Results

International players covered the most total distance per match (International players 5250 ± 1664 m, National players 4113 ± 885 m, Youth players 3436 ± 1026 m, p < 0.003 for main effect) and covered more distance at >21 km/h (i.e. high speed running; International players 73 ± 62 m, National players 31 ± 28 m, Youth players 20 ± 4 m, p < 0.003). Player
Load was greatest in International players (426 ± 143 AU) compared to National players (391 ± 84 AU) and Youth players (290 ± 4 0 AU) (p < 0.001). s
RPE was lower for International players (352 ± 77 AU) and National players (398 ± 58 AU) compared with Youth players (499 ± 171 AU) (p < 0.005).

Conclusions

The external workload of women’s T20 cricket matches became greater as the level of competition increased from Youth to National to International, but Youth players perceive the match demands as greater.

Are children with higher self-reported wellbeing and perceived motor competence more physically active? A longitudinal study

03-10-2019 – Ebonee L. Visser, Emiliano Mazzoli, Trina Hinkley, Natalie J. Lander, Till Utesch, Lisa M. Barnett

Journal Article

Objectives

Self-perceptions such as perceived motor competence and psychosocial wellbeing have been identified as important to children’s physical activity. The study’s purpose was to explore whether perceived motor competence and psychosocial wellbeing were determinants of physical activity, one year after a baseline assessment.

Design

Longitudinal study.

Methods

A total of 134 children (65.7% boys, 34.3% girls) aged 6–7 years at baseline (2016), and 7–8 years at follow-up (2017) were included in this study. Pearson’s correlations assessed associations at baseline and follow-up between moderate- to vigorous-intensity physical activity (MVPA) (accelerometers) and (i) total perceived motor competence and subdomains (the pictorial scale of Perceived Movement Skill Competence) and (ii) psychosocial wellbeing and sub-domains — Kid
KINDL KINDer Lebensqualitätsfragebogen: Children Quality of Life Questionnaire (KINDLR). Variables identified as significant in Pearson’s correlations were included in mixed model analyses, adjusting for accelerometer wear time, sex and age.

Results

Baseline perceived object control skills was associated with MVPA at follow-up (r = 0.38, p < 0.001), but perceived locomotor skills were not. Self-esteem was the only subdomain of psychosocial wellbeing that demonstrated significant association with MVPA at baseline (r = 0.21, p < 0.05). Perceived object control (B = 1.36, p = 0.019, 95% CI 0.23, 2.50) and self-esteem (B = 0.32, p = 0.001, 95% CI 0.13, 0.50) positively predicted MVPA; albeit with small effects.

Conclusions

Focusing on improving children’s perceived object control and self-reported self-esteem may contribute to children’s physical activity participation.

Investigating the reproducibility of maximal oxygen uptake responses to high-intensity interval training

14-10-2019 – Michael Del Giudice, Jacob T. Bonafiglia, Hashim Islam, Nicholas Preobrazenski, Alessandra Amato, Brendon J. Gurd

Journal Article

Objectives

To test the hypothesis that observed maximal oxygen uptake (VO2max) and time to fatigue (TTF) responses to two identical periods of standardized high-intensity interval training are reproducible.

Design

Fourteen recreationally active and healthy young males completed two identical four-week periods of high-intensity interval training (4 × 4-min intervals at 90–95% maximum heart rate HRmax separated by 3-min periods of active recovery at 70–75% HRmax). Training periods were separated by a three-month washout period.

Methods

VO2max and TTF were assessed via incremental tests with supramaximal verification before and after each training period. Pearson correlation coefficients (r), intraclass correlation coefficients (ICC), and within-subjects coefficients of variation (CV) were used to assess reproducibility of observed VO2max and TTF responses.

Results

VO2max and TTF values before the second training period were not significantly higher than baseline values and there were no significant (p > 0.05) interaction effects (period 1: VO2max: +4.04 ± 2.29 m
L/kg/min, TTF: +70.75 ± 35.87 s; period 2: VO2max: +2.83 ± 2.74 m
L/kg/min, TTF: +83.46 ± 34.55 s). We found very weak-to-moderate correlations and poor reproducibility for observed VO2max (m
L/kg/min: r = 0.40, ICC = 0.369, CV = 74.4) and TTF (r = 0.11. ICC = 0.048, CV = 45.6) responses to training periods 1 and 2.

Conclusions

Our ANOVA results confirmed that the three-month washout period returned VO2max and TTF levels to baseline and prevented carryover effects. Contrary to our hypothesis, our results suggest that individual observed VO2max and TTF responses to identical training stimuli are not reproducible.

Psychosocial mediators of screen time reduction after an intervention for students from schools in vulnerable areas: A cluster-randomized controlled trial

24-09-2019 – Alexsandra da Silva Bandeira, Kelly Samara Silva, João Luiz Dornelles Bastos, Diego Augusto Santos Silva, Adair da Silva Lopes, Valter Cordeiro Barbosa Filho

Journal Article

Objectives

To investigate whether psychosocial variables mediate the effect of a multicomponent intervention on screen time reduction among Brazilian students from schools located in vulnerable areas.

Design

A cluster-randomized controlled trial with a 4-month follow-up.

Methods

This study was conducted with 1085 students (548 in the intervention group and 537 in the control group), aged 11–17 years. The intervention strategies focused on training teachers, increasing opportunities for physical activity at school, and reducing screen time, as well as health education. The questionnaire was administered before and after intervention with questions about the amount of time spent on TV and computer/video games on weekdays and weekend days (combined screen time). The potential psychosocial mediators (attitude, self-efficacy, family and school support) were measured through validated scales. Socioeconomic status was used as control variable. Multilevel mediation analyses were conducted using a product-of-coefficients test.

Results

Psychosocial factors were not mediators of the effect of the intervention on screen time. The intervention significantly improved school support for both sexes (boys: 1.307; girls: 0.759; p < 0.05) and older students (1.154; p < 0.001). Attitude (boys: −0.228; 11–13 years: −0.133; 14–17 years: −0.152; p < 0.05) and self-efficacy scales (boys: −0.040; girls: −0.104; 11–13 years: −0.048; 14–17 years: −0.100; p < 0.05) were associated with reduced screen time.

Conclusions

The intervention produced a significant improvement of school support for both sexes, as well as older students. Enhancing attitude and self-efficacy may be a useful strategy for reducing screen time among boys and students of any age groups.

Trial registration

Clinical
Trials.
Gov: NCT02439827. Registration date: May 3, 2015.

Non-surgical treatment of patellar tendinopathy: A systematic review of randomized controlled trials

14-10-2019 – Trevor Vander Doelen, Wilma Jelley

Journal Article, Review

Study design

Systematic review of randomized controlled trials.

Objectives

To determine the most effective non-surgical treatment interventions for reducing pain and improving function for patients with patellar tendinopathy.

Methods

Studies considered for this systematic review were from peer-reviewed journals published between January 2012 and September 2017. All included studies used a visual analogue scale (VAS) to evaluate the participant’s pain. The majority of the included studies also used the Victorian Institute of Sport Assessment Patellar Tendinopathy (VISA-P questionnaire) to assess participant’s symptoms and function.

Results

Nine randomized controlled trials fit the inclusion criteria and were analyzed. The results of three studies supported the use of isometric exercise to reduce pain immediately. One study found patellar strapping and sports taping to be effective for reduction in pain during sport and immediately after. Eccentric exercise, Dry Needling (DN) (2 studies), injections with Platelet Rich Plasma (PRP), Autologous Blood Injection (ABI), and saline were found to have a more sustained effect on reducing pain and improving knee function.

Conclusion

Isometric exercise, patellar strapping, sports taping, eccentric exercise, injections with PRP, ABI, and saline and DN demonstrated a short-term pain relieving and functional improvement effect in subjects with patellar tendinopathy. Longer term follow up on interventions involving eccentric exercise, DN, and injections with PRP, ABI and saline showed sustained pain reduction and improvement in knee function.

Level of evidence

Level 1.

The associations of early specialisation and sport volume with musculoskeletal injury in New Zealand children

24-09-2019 – Jody McGowan, Chris Whatman, Simon Walters

Journal Article

Objective

To investigate associations of early specialisation (highly specialised before age 13 years) and sport participation volume with injury history in New Zealand children.

Design

Cross-sectional survey study.

Methods

Children attending a national sports competition were invited to complete a questionnaire capturing specialisation level (high, moderate or low), participation volume and injury history. Multiple logistic regression was used to investigate associations between variables.

Results

Nine hundred and fourteen children (538 female) completed the questionnaire. After adjusting for age, sex and hours of weekly sport participation, the odds of reporting an injury history were not significantly higher for early specialised children compared to children categorised as low specialisation (OR = 0.88; CI = 0.59–1.31; p = 0.53). Participating in more hours of sport per week than age in years (OR = 2.42; CI = 1.27–4.62; p = 0.02), playing one sport for more than 8 months of the year (OR = 1.60; CI = 1.07–2.36; p = 0.02), or exceeding a 2:1 weekly ratio of organised sport to recreational free-play hours (OR = 1.52; CI = 1.08–2.15; p = 0.02), increased the odds of reporting a ‘gradual onset injury’.

Conclusion

Early specialisation in one sport did not increase the odds of reporting a history of injury. Exceeding currently recommended sport participation volumes was associated with increased odds of reporting a history of gradual onset injury.

Exercise in the first week following concussion among collegiate athletes: Preliminary findings

17-09-2019 – David R. Howell, Anna N. Brilliant, Jessie R. Oldham, Brant Berkstresser, Francis Wang, William P. Meehan

Journal Article

Objectives

Our purpose was to examine the association between exercise after concussion with symptom severity, postural control, and time to symptom-resolution.

Design

Longitudinal cohort.

Methods

Collegiate athletes (n = 72; age = 20.2 ± 1.3 years; 46% female) with concussion completed a symptom questionnaire at initial (0.6 ± 0.8 days post-injury) and follow-up (2.9 ± 1.4 days post-injury) evaluations, and a postural control assessment at follow-up. Participants were grouped into those who exercised in between the time of injury and the follow-up evaluation and those who did not. Decisions regarding post-concussion exercise were made by a sports medicine team consisting of a single team physician and athletic trainers.

Results

Thirteen athletes were not included in the current study, resulting in an 85% response rate. Thirteen of the athletes who completed the study exercised between evaluations (18%). There was no symptom resolution time difference between groups (median = 13 IQR = 7–18 days vs. 13 7–23 days; p = 0.83). Symptom ratings were similar between groups at the acute post-injury assessment (median PCSS = 18.5 7.5–26 vs. 17 14–40; p = 0.21), but a main effect of group after adjusting for time from injury to assessment indicated the exercise group reported lower symptom severity than the no exercise group across both assessments (p = 0.044). The dual-task gait speed of the exercise group was higher than the no exercise group (0.90 ± 0.15 vs. 0.78 ± 0.16 m/s; p = 0.02).

Conclusions

Athletes who were recommended aerobic exercise after concussion did not have worse outcomes than those who were not. Exercise within the first week after concussion does not appear to be associated with detrimental clinical outcomes.

From accelerometer output to physical activity intensities in breast cancer patients

21-09-2019 – Maike G. Sweegers, Laurien M. Buffart, Rosalie J. Huijsmans, Inge R. Konings, Annette A. van Zweeden, Johannes Brug, Mai J.M. Chinapaw, Teatske M. Altenburg

Journal Article

Objectives

We aimed to investigate accelerometer output corresponding to physical activity intensity cut-points based on percentage of peak oxygen consumption (%VO2peak) and Metabolic Equivalent of Task (MET) value in women treated for breast cancer.

Design

Laboratory study.

Methods

Fifty female patients shortly after completion of treatment for breast cancer were included. VO2peak was determined during a cardiopulmonary exercise test. Subsequently, patients performed ten activities with different intensities while wearing an accelerometer on the right hip and a mobile oxycon to assess oxygen consumption. We studied the relationship between energy expenditure (expressed as %VO2peak and MET-value) and accelerometer output (in counts per minute (cpm)) with linear regression analyses. We determined accelerometer output corresponding to physical activity intensity cut-points (40% and 60%VO2peak; 3 and 6 MET) using regression equations.

Results

VO2peak was 22.4 m
L/kg/min (SD 5.2) and resting metabolic rate was 3.1 m
L/kg/min (SD 0.6). Accelerometer output corresponding to the cut-points for moderate (40% VO2peak) and vigorous intensity (60% VO2peak) were 1123 and 1911, respectively. The analyses based on MET-values resulted in accelerometer output of 1189 cpm for the moderate (3 MET) and 2768 cpm for the vigorous intensity cut-point (6 MET).

Conclusions

Accelerometer outputs for moderate and vigorous intensity physical activity were lower than commonly used cut-points (i.e. 1952 and 5724 cpm), irrespective of the method used to express energy expenditure (%VO2peak versus MET-value). Thus, categorizing physical activity intensities based on general-population cut-points, may underestimate physical activity intensities for women treated for breast cancer.

Altitude exposure as a training & iron overload management strategy post leukemia

19-09-2019 – Benjamin G. Serpell, Stephen Freeman, David Ritchie, Philip Choi, Julien D. Périard, Avish P. Sharma

Journal Article

Objectives

To examine iron stores, hemoglobin mass, and performance before, during and after intermittent altitude exposure in a professional male rugby player experiencing iron overload following blood transfusions for treatment for acute myeloid leukemia.

Design

Longitudinal, repeated measures, single case-study.

Methods

The player was followed prior to (control), and during (study), an in-season block of altitude training. During the control period two venesections were performed for a total of 750 m
L of blood removal. Internal and external training load, match statistics, blood volume, plasma volume, haemoglobin mass, serum ferritin and reticulocyte count were monitored throughout.

Results

During the control period serum ferritin declined following the two venesections (∼51%) as did haemoglobin mass (∼2%), reticulocyte count remained stable. During the study period serum ferritin further declined (∼30%), however haemoglobin mass and reticulocyte count increased (∼4% and ∼14% respectively). Internal training load for the control and study period was similar, however external training load was lower in the study period. Match statistics were not favourable for the player during the control period, however they improved during the study period.

Conclusions

This case supports the theory that individuals with elevated iron availability are well placed to achieve increases in haemoglobin mass. Furthermore, although therapeutic venesections may still be required to manage iron overload, the addition of altitude exposure may be a method to assist in reducing total body iron by means of mobilising available (excessive) iron to incorporate into haemoglobin. Altitude exposure did not hinder the players’ performance. Further research is encouraged.

The neuromuscular, endocrine and mood responses to a single versus double training session day in soccer players

19-09-2019 – W. Sparkes, A.N. Turner, C.J. Cook, M. Weston, M. Russell, M.J. Johnston, L.P. Kilduff

Journal Article

Objectives

This study profiled the 24 h neuromuscular, endocrine and mood responses to a single versus a double training day in soccer players.

Design

Repeated measures.

Methods

Twelve semi-professional soccer players performed small-sided-games (SSG’s; 4 vs 4 + goalkeepers; 6 × 7-min, 2-min inter-set recovery) with neuromuscular (peak-power output, PPO; jump height, JH), endocrine (salivary testosterone, cortisol), and mood measures collected before (pre) and after (0 h, +24 h). The following week, the same SSG protocol was performed with an additional lower body strength training session (back-squat, Romanian deadlift, barbell hip thrust; 4 × 4 repetitions, 4-min inter-set recovery; 85% 1 rep-max) added at 2 h after the SSG’s.

Results

Between-trial comparisons revealed possible to likely small impairments in PPO (2.5 ± 2.2 W kg−1; 90% Confidence Limits: ±2.2 W kg−1), JH (−1.3; ±2.0 cm) and mood (4.6; ±6.1 AU) in response to the double versus single sessions at +24 h. Likely to very likely small favourable responses occurred following the single session for testosterone (−15.2; ±6.1 pg ml−1), cortisol (0.072; ±0.034 ug dl−1) and testosterone/cortisol ratio (−96.6; ±36.7 AU) at +24 h compared to the double session trial.

Conclusions

These data highlight that performance of two training sessions within a day resulted in possible to very likely small impairments of neuromuscular performance, mood score and endocrine markers at +24 h relative to a single training session day. A strategy of alternating high intensity explosive training days containing multiple sessions with days emphasising submaximal technical/tactical activities may be beneficial for those responsible for the design and delivery of soccer training programs.

Land- versus water-walking interventions in older adults: Effects on body composition

12-09-2019 – Louise H. Naylor, Barbara A. Maslen, Kay L. Cox, Angela L. Spence, Elisa Robey, Andrew Haynes, Howard H. Carter, Nicola T. Lautenschlager, Nicola D. Ridgers, Carmela Pestell, Daniel J. Green

Journal Article

Objectives

Increasing physical activity is a priority worldwide, including for older adults who may have difficulty performing traditional forms of exercise, and for whom retention of muscle mass is an important consideration. Water-based exercise may provide an alternative if benefits are comparable. We compared the impact on body composition of 24-week water- versus land-walking interventions in healthy but inactive older adults.

Design

Randomised, controlled trial.

Methods

72 participants (62.5 ± 6.8 yr) were randomised to a land-walking (LW), water-walking (WW) or control (C) group in a supervised centre-based program. The exercise groups trained 3 times/week at matched intensity (%HRR), increasing from 40–45% to 55–65% heart rate reserve (HRR). Height, weight, body mass index (BMI), waist and hip girths were recorded; dual X-ray absorptiometry (DXA) provided fat and lean tissue masses. Participants were re-assessed 24 weeks after completion of the intervention.

Results

There were no significant changes in body mass or BMI following either exercise protocol, however central adiposity was reduced in both exercise groups, and the WW group increased lower limb lean mass. These benefits did not persist over the follow-up period.

Conclusions

Exercise can confer beneficial effects on body composition which are not evident when examining weight or BMI. Both WW and LW improved body composition. Water walking can be recommended as an exercise strategy for this age group due to its beneficial effects on body composition which are similar to, or exceed, those associated with land-walking. For benefits to persist, it appears that exercise needs to be maintained.

Quantifying cycling as a foundational movement skill in early childhood

04-09-2019 – Jennifer A. Kavanagh, Johann Issartel, Kieran Moran

Journal Article

Objectives

The addition of cycling to the fundamental movement phase of the motor development model has been proposed. Lifelong physical activity behaviours, like cycling, are established during childhood and it is vital that research focuses on these skills. In order to determine the position of cycling within this newly proposed model, the learning process of this skill must be examined. The current paper will quantify the skill of cycling as a learning process and investigate cycling’s place as a Foundational Movement Skill. Investigation into whether a composite score could be derived from combining fundamental movement skills proficiency scores and ability on a balance bike (as a measure of the learning process of cycling) will also be conducted.

Design and Methods

Ninety-seven preschool children were assessed on ability on a balance bike (bike with no pedals) using two separate timed tracks (straight and curved) and fundamental movement skill proficiency. Data analysis included descriptive statistics, Pearson product-moment correlations and principal axis factoring.

Results

Statistically significant correlations were found between ability on a balance bike and all three subcomponents of fundamental movement skills (locomotor, object-control & stability). Principal axis factoring revealed the presence of one component that all four variables could explain.

Conclusion

Ability on a balance bike is a standalone Foundational Movement Skill and is not a representation of locomotor, object-control or stability. Furthermore, ability on a balance bike can be combined with locomotor, object-control and stability to produce an overall composite score for Foundational Movement Skills.