Journal of Science and Medicine in Sport

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.

Effects of flexibility and strength interventions on optimal lengths of hamstring muscle-tendon units

19-10-2019 – Shangxiao Li, William E. Garrett, Thomas M. Best, Hanjun Li, Xianglin Wan, Hui Liu, Bing Yu

Journal Article

Objectives

The aim of the present study was to determine the effects of altering both hamstring flexibility and strength on hamstring optimal lengths.

Design

Controlled laboratory study.

Methods

A total of 20 male and 20 female college students (aged 18–24 years) participated in this study and were randomly assigned to either a flexibility intervention group or a strength intervention group. Passive straight leg raise and isokinetic strength test were performed before and after interventions. Paired T-tests were performed to determine hamstring flexibility or strength intervention effects on hamstring optimal lengths.

Results

Male participants in the flexibility intervention group significantly increased range of hip joint flexion (P = 0.001) and optimal lengths of semimembranosus and biceps long head (P ≤ 0.026). Male participants in the strength intervention group significantly increased hamstring strength (P = 0.001), the range of hip joint flexion (P = 0.037), and optimal lengths of all three bi-articulated hamstring muscles (P ≤ 0.041). However, female participants did not significantly increase their hamstring optimal lengths in either intervention groups (P ≥ 0.097) although both groups significantly increased the range of hip joint flexion and strength (P ≤ 0.009).

Conclusion

Hamstring optimal lengths can be modified through flexibility intervention as well as strength intervention for male participants, but not for female participants in this study. Hamstring optimal lengths should be considered as hamstring flexibility measures in future prospective studies to identify potentially modifiable risk factors for hamstring injury.

An evaluation of the training determinants of marathon performance: A meta-analysis with meta-regression

11-11-2019 – Cailbhe Doherty, Alison Keogh, James Davenport, Aonghus Lawlor, Barry Smyth, Brian Caulfield

Journal Article, Review

Objectives

Marathoners rely on expert-opinion and the anecdotal advice of their peers when devising their training plans for an upcoming race. The accumulation of results from multiple scientific studies has the potential to clarify the precise training requirements for the marathon. The purpose of the present study was to perform a systematic review, meta-analysis and meta-regression of available literature to determine if a dose-response relationship exists between a series of training behaviours and marathon performance.

Design

Systematic review, meta-analysis and meta-regression.

Methods

A systematic search of multiple literature sources was undertaken to identify observational and interventional studies of elite and recreational marathon (42.2 km) runners.

Results

Eighty-five studies which included 137 cohorts of runners (25% female) were included in the meta-regression, with average weekly running distance, number of weekly runs, maximum running distance completed in a single week, number of runs ≥32 km completed in the pre-marathon training block, average running pace during training, distance of the longest run and hours of running per week used as covariates. Separately conducted univariate random effects meta-regression models identified a negative statistical association between each of the above listed training behaviours and marathon performance (R2 0.38-0.81, p < 0.001), whereby increases in a given training parameter coincided with faster marathon finish times. Meta-analysis revealed the rate of non-finishers in the marathon was 7.27% (95% CI 6.09%–8.65%).

Conclusions

These data can be used by athletes and coaches to inform the development of marathon training regimes that are specific to a given target finish time.

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.

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.

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.

Individual, social and neighbourhood correlates of cycling among children living in disadvantaged neighbourhoods

27-08-2019 – Lisa Bell, Anna Timperio, Jenny Veitch, Alison Carver

Journal Article

Objectives

To describe cycling behaviours and examine individual, social and neighbourhood correlates of cycling among children living in socio-economically disadvantaged neighbourhoods.

Design

Cross-sectional.

Methods

Mothers of 289 children (46% boys) aged 8–15 (mean 12 ± 2.2) years living in disadvantaged neighbourhoods in Victoria, Australia were surveyed about their child’s cycling frequency and duration in a typical week. Perceptions of cycling, cycling ability, cycling behaviours and road safety were proxy- and self-reported by mothers. Shortest road distance from home to school was determined using a Geographic Information System. Multivariable logistic regression analyses examined associations between individual, social and neighbourhood variables and cycling frequency (>once/week) and duration (>60 min/week).

Results

Overall, 70% of boys and 49% of girls cycled > once/week; rates of cycling for >60 min/week were 60% and 32%, respectively. Children had greater odds of cycling > once/week if they enjoyed cycling for fun (OR = 13.3, 95%CI = 2.0, 86.9). Children had greater odds of cycling for >60 min/week if they enjoyed cycling for fun (OR = 17.1, 95%CI = 1.7, 167.7) or if they were allowed to cycle on main roads (OR = 3.2, 95%CI = 1.1, 9.1). Children who had to cross several roads to access play areas had lower odds of cycling for >60 min/week (OR = 0.3, 95%CI = 0.1, 0.7).

Conclusions

Future research should investigate strategies to increase children’s enjoyment of cycling, independent mobility and safe access by cycling to key destinations such as play areas.

Concurrent validity of the ActiGraph GT3X+ and activPAL for assessing sedentary behaviour in 2–3-year-old children under free-living conditions

27-08-2019 – João R. Pereira, Eduarda Sousa-Sá, Zhiguang Zhang, Dylan P. Cliff, Rute Santos

Journal Article

Objectives

Acti
Graph accelerometer cut-points are commonly used to classify sedentary behaviour (SB) in young children. However, they vary from 5counts/5 s to 301counts/15 s, resulting in different estimates and inconsistent findings. The aim was to examine the concurrent validity of Acti
Graph GT3X + cut-points against the activ
PAL for measuring SB in 2–3-year-olds during free-living conditions.

Design

Observational validation-study.

Methods

Sixty children were fitted with the activ
PAL and Acti
Graph simultaneously for at least 2 h. Nine Acti
Graph cut-points ranging from 60 to 1488 counts per minute were used to derive SB. Bland & Altman plots and equivalent tests were performed to assess agreement between methods.

Results

Estimates of SB according to the different Acti
Graph cut-points were not within the activ
PAL ±10% equivalent interval (-4.05; 4.05%). The Acti
Graph cut-points that showed the lower bias were 48counts/15 s (equivalence lower limit: p =  0.597; equivalence upper limit: p < 0.001; bias: -4.46%; limits of agreement Lo
A: -21.07 to 30.00%) and 5counts/5s (equivalence lower limit: p < 0.001; equivalence upper limit: p =  0.737; bias: -5.11%; Lo
A: 30.43 to 20.20%). For the 25counts/15s, 37counts/15s and 48counts/15s Acti
Graph cut-points, the upper limits were within the equivalent interval (p < 0.001) but not the lower limits (p > 0.05). When using the 5counts/5s and 181counts/15s Acti
Graph cut-points, lower limits were within the equivalent interval (p < 0.001) but not the upper limits (p > 0.05). Confidence intervals of the remaining Acti
Graph cut-points lie outside the equivalent interval.

Conclusions

Although none of the Acti
Graph cut-points provided estimates of SB that were equivalent to activ
PAL; estimates from 48counts/15 s and 5counts/5 s displayed the smallest mean bias (˜5%).

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.

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.

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.

Concussion incidence and time-loss in Australian football: A systematic review

15-11-2019 – Claire McNeel, Gillian M. Clark, Charlotte B. Davies, Brendan P. Major, Jarrad A.G. Lum

Journal Article, Review

Objectives

Australian football is associated with a risk of concussion. However, despite the extensive and varied nature of literature devoted to this issue, concussion incidence has not been systematically evaluated. To address this, we aimed to conduct a meta-analysis of concussion incidence in Australian football.

Design

Systematic review. Prospero registration number: CRD42017064290.

Methods

A systematic search of 14 databases using the terms ‘concussion’, and ‘Australian football’ (and variations) was used to obtain records that reported concussion incidence per 1000 players hours across age, sex, and level-of-play. Data were grouped based on how time-loss was applied to the concussion definition.

Results

Forty-two studies met inclusion criteria. Incidence rates based on a possible time-loss definition per 1000 player hours, ranged from 2.24 to 17.63 at the elite level, and 0.35 to 14.77 at the community/amateur level. Return-to-play details were reported by six studies and only two studies measured head-impacts in real-time. Several limitations were identified with this literature. First, insufficient return-to-play details precluded a meta-analysis of incidence rates. Second, no longitudinal studies across levels-of-play were found. Third, concussion incidence data for junior and female players were notably scarce.

Conclusions

There was limited scope to determine concussion burden (i.e., incidence and severity) and only preliminary data for player exposure to head-impacts. To address these limitations, injury surveillance should capture sufficient information to permit comparisons within and across levels-of-play. This will also help determine the influence of interventions aimed at reducing the frequency and severity of concussive-injuries.

The peak player load™ of state-level netball matches

11-11-2019 – Scott Graham, James Zois, Robert Aughey, Grant Duthie

Journal Article

Objectives

To investigate the peak accelerometer-derived intensity of state-level netball matches and compare differences between positional groupings. Findings will provide guidance for sport science professionals on how to best replicate the most intense passages of play in training settings.

Design

Longitudinal (one season).

Method

Twenty-eight netball athletes across three teams from the same club wore an accelerometer (S5 Optimeye, Catapult sports) for all matches, in one season. Raw acceleration data were downloaded and converted into a vector magnitude (Player Load™) we then quantified the peak intensity over 30-s and one to ten-minute time periods. Positional groupings were created based on the number of thirds on a netball court that a particular position can enter, as this was deemed more appropriate for the current study than the traditional combinations based on tactical requirements. A linear mixed-model with fixed and random effects was utilised along with magnitude-based inferences to determine meaningful differences with 90 % confidence limits (CL).

Results

Across all time periods post 30-s, only one comparison was not meaningfully different i.e. three-thirds v two-thirds at the one-minute timepoint (effect size: 0.27, CL −0.05 to 0.60).

Conclusions

Findings justify that netball athletes, depending on positional group defined by this study, should train at different intensities dependent on a specified duration. Conditioning professionals and coaches should design training drills that best replicate the peak intensity of match play. This may improve an athlete’s physical performance capacity during highly exertive periods of competition, which regularly occur at critical moments in play.

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.

A cross-sectional comparison between cardiorespiratory fitness, level of lesion and red blood cell distribution width in adults with chronic spinal cord injury

29-09-2019 – Tom E. Nightingale, Gurjeet S. Bhangu, James L.J. Bilzon, Andrei V. Krassioukov

Journal Article

Objectives

To assess; (1) differences in red blood cell distribution width between individuals with chronic (>1 year), motor-complete cervical (n = 21), upper-thoracic (n = 27) and thoracolumbar (n = 15) spinal cord injury and, (2) associations between red blood cell distribution width and cardiorespiratory fitness.

Design

Prospective multi-center, cross-sectional study.

Methods

Peak oxygen uptake was determined using an upper-body arm-crank exercise test to volitional exhaustion and red blood cell distribution width was measured using an automated hematology system.

Results

There were significant (p < 0.009) differences between groups classified by level of injury in absolute and relative peak oxygen uptake, peak power output and red blood cell distribution width. A significant (p < 0.001) large negative association (r = −0.524) was found between relative peak oxygen uptake and red blood cell distribution width. Unbiased recursive partitioning, while revealing study site specific differences in red blood cell distribution width, identified homogenous subgroups based specifically on cardiorespiratory fitness irrespective of additional demographic and injury characteristics.

Conclusion

The strong negative association between cardiorespiratory fitness and red blood cell distribution width in individuals with paraplegia parallel those previously observed in non-disabled individuals. Higher red blood cell distribution width values are an independent risk factor for increased cardiovascular mortality, heart failure, and coronary heart disease and may reflect several underlying exacerbated metabolic responses such as oxidative stress and systemic inflammation. These data emphasize the importance of maintaining a high aerobic capacity following spinal cord injury.

Fitness, level of lesion and red blood cell distribution in chronic spinal cord injury

12-01-2020 – Gordon S. Waddington

Editorial

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.

A comparison of rolling averages versus discrete time epochs for assessing the worst-case scenario locomotor demands of professional soccer match-play

16-01-2020 – Kieran Ferraday, Samuel P. Hills, Mark Russell, Jordan Smith, Dan J. Cunningham, David Shearer, Melitta McNarry, Liam P. Kilduff

Journal Article

Objectives

To compare fixed epochs (FIXED) and rolling averages (ROLL) for quantifying worst-case scenario (‘peak’) running demands during professional soccer match-play, whilst assessing contextual influences.

Design

Descriptive, observational.

Methods

Twenty-five outfield players from an English Championship soccer club wore 10-Hz microelectromechanical systems during 28 matches. Relative total and high-speed (>5.5 m s−1) distances were averaged over fixed and rolling 60-s to 600-s epochs. Linear mixed models compared FIXED versus ROLL and assessed the influence of epoch length, playing position, starting status, match result, location, formation, and time-of-day.

Results

Irrespective of playing position or epoch duration, FIXED underestimated ROLL for total (∼7–10%) and high-speed (∼12–25%) distance. In ROLL, worst-case scenario relative total and high-speed distances reduced from 190.1 ± 20.4 m min−1 and 59.5 ± 23.0 m min−1 in the 60-s epoch, to 120.9 ± 13.1 m min−1 and 14.2 ± 6.5 m min−1 in the 600-s epoch, respectively. Worst-case scenario total distance was higher for midfielders (∼9−16 m min−1) and defenders (∼3–10 m min−1) compared with attackers. In general, starters experienced higher worst-case scenario total distance than substitutes (∼3.6–8.5 m min−1), but lower worst-case scenario high-speed running over 300-s (∼3 m min−1). Greater worst-case scenario total and high-speed distances were elicited during wins (∼7.3–11.2 m min−1 and ∼2.7–7.9 m min−1, respectively) and losses (∼2.7–5.7 m min−1 and ∼1.4–2.2 m min−1, respectively) versus draws, whilst time-of-day and playing formation influenced worst-case scenario high-speed distances only.

Conclusions

These data indicate an underestimation of worst-case scenario running demands in FIXED versus ROLL over 60-s to 600-s epochs while highlighting situational influences. Such information facilitates training specificity by enabling sessions to be targeted at the most demanding periods of competition.

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.

Pterins as diagnostic markers of exercise-induced stress: a systematic review

11-09-2019 – Angus Lindsay, Steven P. Gieseg

Journal Article, Review

Objectives

To evaluate pterins as diagnostic biomarkers of exercise-induced stress.

Design

Systematic review of the literature.

Methods

MEDLINE, Scopus and Web of Science were searched in March 2019 for relevant literature. We only considered in vivo studies of healthy humans that reported measurement of a pterin(s) in response to exercise or sport with no underlying prior disease or complication. Relevant articles were independently reviewed and resolved by consensus.

Results

We included 29 studies with 644 participants. We classified articles by running/hiking, cycling, rugby, mixed martial arts (MMA) or other. Eighty-six percent of studies measured a significant increase in a pterin in response to exercise. Changes in pterin concentrations were within 24 h of the exercise-stimulus in 79% of studies and 17% measured a change from baseline greater than 48 h post-exercise (49% did not measure or report beyond 48 h). Neopterin or total neopterin (neopterin + 7,8-dihydroneopterin) were the primary pterin measured (28 studies) and they were equally sensitive to exercise regardless of whether the stimulus was running, cycling, rugby, MMA or other.

Conclusions

Neopterin and total neopterin increase in response to exercise-induced stress. Pterins may have limited capacity for monitoring long-term stress beyond 48 h but further research is required.

Do the landing mechanics of experienced netball players differ from those of trained athletes competing in sports that do not require frequent landings?

01-09-2019 – Tyler J. Collings, Adam D. Gorman, Max C. Stuelcken, Daniel B. Mellifont, Mark G.L. Sayers

Journal Article

Objectives

This study examined whether young (15–19 years old) high-performance netball players exhibit different landing mechanics compared to female controls who do not participate in sports requiring frequent landings.

Design

Comparative, cross-sectional.

Methods

Lower limb kinematics and kinetics from 23 youth high performance female netball players (age: 17.5 ± 1.7 years, height: 1.77 ± 0.06 m, mass: 66.5 ± 6.33 kg, netball experience: 8.5 ± 2.3 years) were compared to data from 23 females (age: 22.0 ± 3.2 years, height: 1.70 ± 0.05 m, mass: 64.4 ± 6.7 kg) who were involved in competitive sport, but had minimal experience playing a jump-landing sport. The jump landing task required participants to perform a countermovement jump and grab a netball suspended at 85% of the participant’s maximum jump height. On random trials the ball was raised rapidly to 100% maximum jump height as the participant initiated her jump.

Results

The netball group landed with significantly less contribution from the knee extensors to total work for the non-preferred leg (P < 0.001, ds = 1.10) than the inexperienced group. Although no other significant differences were found between groups, there were several small to moderate differences in several of the key biomechanical variables identified as being risk factors for ACL injury or associated with ACL strain.

Conclusions

Both groups had similar knee valgus and internal rotation angles and moments, with nearly all participants presenting with relatively poor frontal plane knee control. Overall, results suggest that experience playing a netball may not be enough to develop low-risk landing mechanics.

Isolated effects of caffeine and sodium bicarbonate ingestion on performance in the Yo-Yo test: A systematic review and meta-analysis

31-08-2019 – Jozo Grgic, Alessandro Garofolini, Craig Pickering, Michael J. Duncan, Grant M. Tinsley, Juan Del Coso

Journal Article, Review

Objectives

To conduct a systematic review and a meta-analysis of studies exploring the effects of caffeine and/or sodium bicarbonate on performance in the Yo-Yo test.

Design

Systematic review and meta-analysis.

Methods

A total of six databases were searched, and random-effects meta-analyses were performed examining the isolated effects of caffeine and sodium bicarbonate on performance in the Yo-Yo test.

Results

After reviewing 988 search records, 15 studies were included. For the effects of caffeine on performance in the Yo-Yo test, the meta-analysis indicated a significant favoring of caffeine as compared with the placebo conditions (p = 0.022; standardized mean difference SMD = 0.17; 95% CI: 0.08, 0.32; +7.5%). Subgroup analyses indicated that the effects of caffeine were significant for the level 2 version of the Yo-Yo test, but not level 1. Four out of the five studies that explored the effects of sodium bicarbonate used the level 2 version of the Yo-Yo test. The pooled SMD favored the sodium bicarbonate condition as compared with the placebo/control conditions (p = 0.007; SMD: 0.36; 95% CI: 0.10, 0.63; +16.0%).

Conclusions

This review demonstrates that isolated ingestion of caffeine and sodium bicarbonate enhances performance in the Yo-Yo test. Given these ergogenic effects, the intake of caffeine and sodium bicarbonate before the Yo-Yo test needs to be standardized (i.e., either restricted or used in the same way before each testing session). Furthermore, the results suggest that individuals competing in sports involving intermittent exercise may consider supplementing with caffeine or sodium bicarbonate for acute improvements in performance.

Key performance indicators in Australian sub-elite rugby union

01-09-2019 – Tim J. Mosey, Lachlan J.G. Mitchell

Journal Article

Objectives

The primary aim of this study was to determine which key performance indicators (PIs) were most important to success in sub-elite rugby union, and whether the analysis of absolute or relative data sets as a method for determining match outcome was stronger than the other.

Methods

Data was taken from 17 PIs from 76 matches across the 2018 Queensland Premier Rugby Union season. A random forest classification model was created using these data sets based on win/loss outcomes.

Results

The random
Forest model classified 53 from 73 losses (72.6%) and 53 from 73 wins for an overall percentage accuracy of 72.6%. The random
Forest model based on the relative data set classified 57 from 73 losses (78.1%) and 57 from 73 wins for an overall percentage accuracy of 78.1%. Mc
Nemar’s value of p = 0.84 confirmed that the relative data model did not outperform the absolute data set. There were positive associations between match outcome and relative number of kicks in play, meters carried, turnovers conceded and initial clean breaks.

Conclusions

Outcomes in Queensland Premier Rugby can be predicted using relative and absolute data sets, though the difference between absolute and relative set usage was not as substantial as in professional rugby. Absolute and relative data sets can be used to create match strategies and assess match performance. A game plan based around an out of hand kicking game and accumulating more metres than the opposition, whilst minimising turnovers when in possession were key to success.

Evaluation of a sport-specific field test to determine maximal lactate accumulation rate and sprint performance parameters in running

04-09-2019 – Oliver J. Quittmann, Daniel Appelhans, Thomas Abel, Heiko K. Strüder

Journal Article

Objectives

The aim of this study was to examine the reliability of maximal lactate accumulation rate (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax) and sprint performance parameters in running and assess different approaches to determine alactic time interval (talac).

Design

Sixteen competitive runners (female = 5; male = 11) performed three trials (T1, T2 and T3) of an all-out 100-m sprint test separated by 48 h.

Methods

Time to cover the 100 m was determined by using a photoelectric light-barrier (t100,LB) and a stop-watch (t100,SW). Throughout the sprints, velocity was measured using a laser velocity guard (LAVEG) to estimate maximal velocity (vmax) and power (Pmax). The talac was calculated as the time when power decreased by 3.5% (tpmax-3.5%) and interpolated based on the sprint time (tinter,LB and tinter,SW). Reliability was assessed using intraclass correlation coefficient (ICC), typical error (TE) and smallest worthwhile change (SWC).

Results

After initial familiarisation, t100, tinter, vmax, Pmax and <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax attained excellent reliability (ICC ≥ 0.90), whereas tpmax−3.5% attained moderate reliability (ICC = 0.518). The reliability of <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax was higher when tinter,LB or tinter,SW were used (ICC = 0.960) compared to using tpmax−3.5% (ICC = 0.928). At T1, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax was significantly higher when stop-watch measurements were used. There was no difference between tpmax−3.5% and the interpolated time intervals and the associated <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax-estimates.

Conclusions

In running, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax and sprint performance parameters can easily and high-reliably be measured using this sport-specific field test. Interpolating talac results in similar and more reliable values of <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.gif” class=”math”>V˙Lamax. To improve the reliability and accuracy of the stop-watch estimate, a familiarisation should be performed.

Changes in performance markers and wellbeing in elite senior professional rugby union players during a pre-season period: Analysis of the differences across training phases

27-08-2019 – Adam Grainger, Ross Neville, Massimiliano Ditroilo, Paul Comfort

Journal Article

Objectives

To assess the magnitude of change and association with variation in training load of two performance markers and wellbeing, over three pre-season training blocks, in elite rugby union athletes.

Design

Observational.

Methods

Twenty-two professional players (age 25 ± 5 years; training age 6 ± 5 years; body mass, 99 ± 13 kg; stature 186 ± 6 cm) participated in this study, with changes in lower (CMJ height) and upper body (bench press mean speed) neuromuscular function and self-reported wellbeing (WB) assessed during an 11-week period.

Results

There was a small increase in CMJ height (0.27, ±0.17 – likely substantial; standardised effect size, ±95% confidence limits – magnitude-based inference) (p = 0.003), bench press speed (0.26, ±0.15 – likely substantial) (p = 0.001) and WB (0.26, ±0.12 – possibly substantial) (p < 0.0001) across the pre-season period. There was a substantial interaction in the effect of training load on these three variables across the three training phases. A two-standard deviation (2SD) change in training load was associated with: a small decrease in CMJ height during the power phase (−0.32, ±0.19 – likely substantial) (p = 0.001); a small reduction in bench press speed during the hypertrophy phase (−0.40, ±0.32 – likely substantial) (p = 0.02); and a small reduction in WB during the strength phase (−0.40, ±0.24 – very likely substantial) (p < 0.0001). The effects of changes in training load across other phases were either likely trivial, only possibly substantial, or unclear.

Conclusions

The effect of training load on performance can vary both according to the type of training stimulus being administered and based on whether upper- or lower-body outcomes are being measured.

Differences in running biomechanics between a maximal, traditional, and minimal running shoe

11-09-2019 – J.J. Hannigan, Christine D. Pollard

Journal Article

Objectives

Previous studies comparing shoes based on the amount of midsole cushioning have generally used shoes from multiple manufacturers, where factors outside of stack height may contribute to observed biomechanical differences in running mechanics between shoes. Therefore, the purpose of this study was to compare ground reaction forces and ankle kinematics during running between three shoes (maximal, traditional, and minimal) from the same manufacturer that only varied in stack height.

Design

Within-participant repeated measures

Methods

Twenty recreational runners ran overground in the laboratory in three shoe conditions (maximal, traditional, minimal) while three-dimensional kinematic and kinetic data were collected using a 3D motion capture system and two embedded force plates. Repeated measures ANOVAs (α = .05) compared biomechanical data between shoes.

Results

While the loading rate was significantly greater in the minimal shoe compared to the maximal shoe, no other differences were seen for the ground reaction force variables. Peak eversion was greater in the maximal and minimal shoe compared to the traditional shoe, while eversion duration and eversion at toe-off were greater in the maximal shoe.

Conclusions

Previously cited differences in ground reaction force parameters between maximal and traditional footwear may be due to factors outside of midsole stack height. The eversion mechanics in the maximal shoes from this study may place runners at a greater risk of injury. Disagreement between previous studies indicates that more research on maximal running shoes is needed.

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

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

Journal Article

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

Objectives

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

Design

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

Methods

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

Results

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

Conclusions

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

Hip adduction and abduction strength and adduction-to-abduction ratio changes across an Australian Football League season

26-08-2019 – Todd A. Lonie, Carly J. Brade, Mark E. Finucane, Angela Jacques, Tiffany L. Grisbrook

Journal Article

Objectives

Pre-season hip strength testing only represents the athlete’s level of conditioning at that time point, and may change over an Australian Football (AF) season. This study aimed to examine if there are changes in hip adduction, abduction and the adduction-to-abduction ratio between preferred and non-preferred kicking legs throughout an AF season. The influence of training load and player characteristics was also examined.

Design

Cross-sectional repeated measures.

Methods

38 uninjured elite AF players were included. Maximal isometric hip adduction and abduction strength were measured at four time points: start of pre-season (T1), end of pre-season (T2), mid-season (T3) and post-season (T4) using a hand held dynamometer with external belt fixation.

Results

Hip adduction strength and hip-adduction-to-abduction ratio were greater in T3 compared to T1 (adduction by 22.71 N, p < 0.001, ratio by 0.15 N, p < 0.001) and hip adduction and abduction were weaker in T4 compared to T1 (adduction by 18.6 N, p = 0.004, abduction by 24.67 N, p < 0.001). No differences were found between the preferred and non-preferred leg in adduction (p = 0.409) or abduction (p = 0.602) strength. There was an interaction between leg and time point for the adduction-to-abduction ratio; at T3 and T4, the ratio of the preferred kicking leg was significantly lower than the non-preferred kicking leg (T3 by 0.14 N, p = 0.020, T4 by 0.15 N, p = 0.019). Training load was not significantly associated with strength changes.

Conclusions

Hip strength does change over an AF season. Regular in-season hip strength testing should occur to more accurately reflect player condition compared to one pre-season measurement.

Kicking off the 2020 Olympic year with a bumper sport and exercise science edition

08-12-2019 – Gordon S. Waddington

Editorial

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.

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.

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 biomechanical stability deficits during unplanned single-leg landings related to specific markers of cognitive function?

20-10-2019 – Florian Giesche, Jan Wilke, Tobias Engeroff, Daniel Niederer, Helena Hohmann, Lutz Vogt, Winfried Banzer

Journal Article

Objectives

Cognitive skills such as working memory or inhibitory control are suggested to have an impact on injury risk during time-constrained athletic movements. Thus, the aim of this study was to gain further insights into the cognitive processes associated with biomechanical stability in unplanned jump-landings.

Design

Cross-sectional.

Methods

Twenty male participants (27 ± 4 years) performed 70 counter-movement jumps with single-leg landings on a pressure plate. Equally balanced and in randomized order, these were to be performed either planned (landing leg indicated before take-off) or unplanned (visual cue during flight). Biomechanical stability was estimated from vertical peak ground reaction force (p
GRF), time to stabilization (TTS), center of pressure path length (COP), and the number of standing errors (ground touch with free leg). In addition, decision-making was assessed as the amount of landing errors (wrong/both feet) in the unplanned condition. Cognitiive function was measured using computerized as well as pen-and-paper-testing.

Results

Unplanned landings produced higher COP values (p < 0.001, d = 1.1) and more standing errors (p < 0.001, d = 0.9) than the pre-planned condition. Decreased postural stability (COP) was related to lower inhibitory control (p = 0.036, r = 0.48). There was a correlation between the increase in standing errors and better cognitive flexibility/working memory (p = 0.037, r = −0.48) and short-term memory (p = 0.028, r = 0.50). The opposite was found for the unplanned landing errors: poor decision-making was associated with deficits in cognitive flexibility/working memory (p = 0.022, r = 0.54) and short-term memory (p = 0.019, r = −0.55).

Conclusions

Cognitive function may be an important, but under-researched moderator of unplanned jump-landing safety. Further research should elucidate the development of training methods aiming to improve movement-related decision-making and landing stability under time constraints.

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.

Serum ferritin distribution in elite athletes

07-01-2020 – Dustin Nabhan, Shane Bielko, Jacob A. Sinex, Kendall Surhoff, William J. Moreau, Yorck Olaf Schumacher, Roald Bahr, Robert F. Chapman

Journal Article

Objectives

It is not uncommon for athletes to be diagnosed with iron deficiency, yet there remains uncertainty whether the prevalence of suboptimal iron status in elite athletes differs from the normal population or warrants routine screening. The purpose of this study is to describe the distribution of serum ferritin (SF) in a cohort of elite athletes.

Design

Retrospective cohort study.

Methods

Electronic health records of 1085 elite adult athletes (570 women, 515 men) from 2012–2017 were examined retrospectively. SF values were compared to published normal population data. The proportion of athletes meeting criterion values for iron deficiency or initiation of treatment was examined.

Results

SF distributions in male athletes were significantly lower than normal males aged 20 to <24 yrs. (χ2 28.8, p < 0.001) and aged 24 to <28 yrs. (χ2 91.9, p < 0.001). SF status was similar in female athletes and normal women aged 20 to <24 yrs. (χ2 9.5, p > 0.05) or aged 24 to <28 yrs. (χ2 11.5, p > 0.05). Using 35 ng/ml as the criterion value for stage one iron deficiency, 15% of male athletes and 52% of female athletes displayed suboptimal iron status.

Conclusions

Male athletes have a significantly lower population distribution of SF values as compared to normative data on healthy males, with 15% of male athletes having suboptimal SF status. The distribution of SF values in elite female athletes did not differ from population values, however approximately half women athletes were iron deficient. These data suggest that iron screening should be considered in both male and female athlete populations.

A systematic review of cognitive assessment in physical activity research involving children and adolescents

09-01-2020 – Levi Wade, Angus Leahy, David R. Lubans, Jordan J. Smith, Mitch J. Duncan

Journal Article, Review

Objectives

To summarise the reporting, administrative requirements and psychometric properties of cognitive measures used in experimental physical activity research conducted with school-aged youth.

Design

Systematic review.

Methods

Five databases (CINAHL, SPORTDiscus, Medline, Embase, and Psychinfo) were searched from inception to October, 2018. Studies meeting the following criteria were eligible for inclusion: experimental study design; apparently healthy youth aged 5–18 years; use of physical activity; and use of a performance-based cognitive test. Reporting, administration requirements, reliability, and validity of the included cognitive measures was extracted.

Results

Included studies (n = 109) used 60 unique cognitive tests. Across the 109 included studies, a total of 181 tests were reported on. Test format (e.g. pen and paper, computer) was specified for 166 (91.7%); administration type (individual or group) for 108 (59.7%); and administration time for 49 (27.1%) of the tests. Of the 181 tests reported on, 72 (39.8%) provided information on either test–retest reliability or internal consistency, and 82 (45.3%) provided at least one form of test validation.

Conclusions

A lack of reporting of test administration time, as well as information on the reliability and validity of included cognitive tasks are notable limitations of studies included in this review. Agreement on a smaller number of tests should be sought to improve the interpretability of future research. The summary provided by this systematic review can be used to inform the selection of performance-based cognitive measures in future physical activity research.

Changes in urinary titin N-terminal fragments as a biomarker of exercise-induced muscle damage in the repeated bout effect

14-01-2020 – Shota Yamaguchi, Katsuhiko Suzuki, Kazue Kanda, Takayuki Inami, Junichi Okada

Journal Article

Objectives

Muscle damage symptoms induced by unaccustomed eccentric contraction exercise can be reduced by repeating the experience several times. This phenomenon is termed the repeated bout effect. Although traditional biochemical markers require invasive blood sampling, biochemical measurements have recently been developed that can be non-invasively performed using urinary titin N-terminal fragment (UTF). However, it is unclear whether UTF can reflect the repeated bout effect. Therefore, the aim of the present study was to clarify whether UTF decreased with the repeated bout effect.

Design

This study compared changes in muscle damage markers between bouts of exercise performed for the first and second time.

Methods

Eight young men performed 30 eccentric exercises of the elbow flexor on the first day of the first week (Bout 1). A second bout of eccentric exercises, same as the first, was performed 2 weeks later, (Bout 2). The dependent variables were muscle soreness (SOR), maximal voluntary isometric contraction (MVIC), range of motion (ROM), creatine kinase (CK), and UTF. All dependent variables were analyzed using two-way analysis of variance.

Results

No significant difference was observed in workload or peak torque between the first and second exercise bouts. SOR as well as CK and UTF were significantly lower and ROM and MVIC were significantly higher in Bout 2 in comparison to Bout 1.

Conclusions

These results suggest that UTF sensitively reflects the repeated bout effect and exercise-induced muscle damage can be non-invasively measured.

The availability of task-specific feedback does not affect 20 km time trial cycling performance or test-retest reliability in trained cyclists

02-01-2020 – David N. Borg, John O. Osborne, Ian B. Stewart, Joseph T. Costello, Jonathon Headrick, Benjamin S. McMaster, Samantha J. Borg, Geoffrey M. Minett

Journal Article

Objectives

This study examined the influence of the availability of task-specific feedback on 20 km time trial (20TT) cycling performance and test-retest reliability.

Design

Thirty trained, club-level cyclists completed two 20TT’s on different days, with (feedback, FB) or without (no-feedback, NFB) task-specific feedback (i.e., power output, cadence, gear and heart rate HR). Elapsed distance was provided in both conditions.

Methods

During trials, ergometer variables and HR were continuously recorded, and a rating of perceived exertion (RPE) was collected every 2 km. Data were analysed using linear mixed-effects models in a Bayesian framework, and Cohen’s d was calculated for standardised differences. The reliability of finish time and mean power output (PO) was determined via multiple indices, including intraclass correlations (ICC).

Results

Performance, pacing behaviour, and RPE were not statistically different between conditions. The posterior mean difference 95% credible interval between TT1 and TT2 for FB and NFB was 10 s −5, 25 and −2 s −17, 14, respectively. In TT2, HR was statistically higher (∼8 b min−1) in FB compared to NFB after 13 km (d = 2.08–2.25). However, this result was explained by differences in maximal HR. Finish time (FB: ICC =  0.99; NFB: ICC = 0.99) and mean power output (FB: ICC = 0.99; NFB: ICC = 0.99) in each condition were substantially reliable.

Conclusions

The availability of task-specific information did not affect 20TT performance or reliability. Except for elapsed distance, task-specific feedback should be withheld from trained cyclists when evaluating interventions that may affect performance, to prevent participants from recalling previous performance settings.

Are nutritional supplements a gateway to doping use in competitive team sports? The roles of achievement goals and motivational regulations

14-01-2020 – Vassilis Barkoukis, Lambros Lazuras, Despoina Ourda, Haralambos Tsorbatzoudis

Journal Article

Objectives

The study investigated the moderating role of achievement goals and motivation regulations on the association between self-reported nutritional supplement (NS) use, doping likelihood, and self-reported doping behaviour among competitive athletes.

Method

Four hundred and ninety seven competitive team sport athletes (64% males; M age = 23.54 years, SD = 5.75) completed anonymous questionnaires measuring self-reported use of prohibited substances and licit NS; beliefs about the “gateway” function of NS; achievement goals; and motivational regulations.

Results

Hierarchical linear regression analysis showed that self-reported doping was associated (Adjusted R2 = 33%) with NS use, a stronger belief that NS use acts as a gateway to doping, amotivation, controlled motivation, mastery approach, and performance avoidance goals. Higher likelihood to use doping substances in the future was associated (Adjusted R2 = 41.7%) with current NS use, stronger belief that NS act as a gateway to doping, autonomous motivation, and performance avoidance goals. A series of moderated regression analyses showed that NS use significantly interacted with mastery approach, mastery avoidance, performance avoidance goals, autonomous motivation controlled motivation, and with amotivation in predicting self-reported doping. Finally, NS use significantly interacted with mastery approach goals, performance avoidance goals, and controlled motivation in predicting future doping likelihood.

Conclusions

Achievement goals and motivational regulations are differentially associated with both doping likelihood and self-reported doping, and may account for the observed association between self-reported NS use and doping substances; thus, providing an alternative explanation to the “gateway hypothesis” that emphasizes the role of motivation.

‘Maths on the move’: Effectiveness of physically-active lessons for learning maths and increasing physical activity in primary school students

14-01-2020 – M. Vetter, H.T. O’Connor, N. O’Dwyer, J. Chau, R. Orr

Journal Article

Objectives

This study evaluated the benefit of physically-active lessons for learning maths multiplication-tables. The impact of the intervention on general numeracy, physical activity (PA), aerobic fitness, body mass index (BMI) and school-day moderate to vigorous PA (MVPA) was also assessed.

Design

Randomised controlled cross-over trial.

Method

Year 3 students (n = 172, mean age 8.4 ± 0.3 years, 48% male) were recruited from 10 classes across two urban primary schools. Participants were randomly assigned to a seated classroom (Classroom) group or physically-active lessons in the playground (Playground) and crossed over to the alternative condition in the subsequent school term. The 6-week intervention comprised 3 × 30 min sessions/week. Multiplication-tables (teacher-designed test) and general maths (standardised test) were assessed pre- and post-intervention. Aerobic fitness was assessed via the shuttle-run. Pre- to post-intervention change scores were compared for analysis and effect sizes (ES) calculated. Total PA and MVPA were assessed with accelerometers in a subset of participants.

Results

Multiplication scores improved significantly more in Playground than Classroom groups (ES = 0.23; p = 0.045), while no significant differences were observed in general numeracy (ES = 0.05; p = 0.66). Total PA and MVPA were substantially higher during Playground than Classroom lessons (ES: total PA = 7.4, MVPA = 6.5; p < 0.001) but there were no differences in PA/MVPA between the groups throughout the rest of the school day. Aerobic fitness improved more in Playground than Classroom groups (ES = 0.3; p < 0.001) while the change in BMI was not different between groups (p = 0.39).

Conclusions

Physically-active lessons may benefit the learning of maths multiplication-tables while favourably contributing to school-day PA/MVPA.

Validity and reliability of isometric tests for the evidence-based assessment of arm strength impairment in wheelchair rugby classification

31-12-2019 – Barry S. Mason, Viola C. Altmann, Michael J. Hutchinson, Victoria L. Goosey-Tolfrey

Journal Article

Objectives

The purpose of this study was to examine the validity and test-retest reliability of a battery of single-joint isometric strength tests, to establish whether the tests could be used for evidence-based classification in wheelchair rugby (WR).

Design

Cross-sectional.

Methods

Twenty male WR athletes with impaired arm strength and thirty able-bodied (AB) participants (15 male, 15 female) performed four isometric strength tests. Each test required three 5-s efforts and examined maximal isometric force for flexion and extension around the shoulder and elbow joint. Test validity was established by comparing differences (Cohen’s effect sizes d) in strength between WR athletes and AB participants. Differences were also explored between male and female AB participants. Twenty AB participants returned for a second visit to establish the test-retest reliability of the test battery.

Results

Significantly lower force values were observed for all isometric strength measures in WR athletes compared to AB participants (p ≤ 0.0005; d ≥ 2.14). Female AB participants also produced significantly less force than male AB participants for all joint actions (p ≤ 0.0005; d ≥ 1.93). No significant differences were identified between trials for any measure of strength, with acceptable levels of test-retest reliability reported (ICCs ≥ 0.97, SEM ≤ 19.3 N and CV ≤ 8.4%).

Conclusions

The current results demonstrated the validity of a battery of isometric strength tests, suggesting they can be used to reliably infer strength impairment in WR athletes, which is a pre-requisite when working towards evidence-based classification in Paralympic sport.

Changes in subjective mental and physical fatigue during netball games in elite development athletes

31-12-2019 – Suzanna Russell, David Jenkins, Shona Halson, Vincent Kelly

Journal Article

Objectives

To assess the magnitude of changes in, and relationships between, physical and mental fatigue pre-to-post match in elite development netballers.

Design

Observational.

Methods

Twelve female netballers (21.3 ± 2.9 years) competing in the Australian Netball League reported perceptual measures of mental and physical fatigue pre- and post-match on 12 separate competition occasions. Minutes played, to allow for calculation of weighted changes (ratings proportional to playing time), positional groups and performance analysis variables were also assessed.

Results

Post-match ratings were higher (p < 0.01) than pre-match for both mental (pre: 31.02 ± 19.28; post: 44.73 ± 24.47) and physical fatigue (pre: 28.86 ± 15.37; post: 47.21 ± 24.67). The correlation coefficient between change in mental and physical fatigue (r = 0.37, p < 0.01) revealed a shared variance of 13.9%. Acute changes in mental fatigue were related to minutes played (r = 0.32, p < 0.01) as was change in physical fatigue (r = 0.59, p < 0.01). No differences in change in mental fatigue were found between positional groups (p = 0.07) though change in physical fatigue was higher for shooters compared to defenders (p < 0.05). Performance variables revealed no relationships with mental or physical fatigue, with the exception of turnover number with both post-match weighted physical (r= -0.23, p < 0.01) and weighted-change in physical fatigue (r = −0.16, p < 0.05).

Conclusions

Mental and physical fatigue were found to increase across netball matches in elite development athletes. Mental fatigue emerged as a largely separate construct to physical fatigue.

Assessing the whole-match and worst-case scenario locomotor demands of international women’s rugby union match-play

29-12-2019 – Emily Sheppy, Samuel P. Hills, Mark Russell, Ryan Chambers, Dan J. Cunningham, David Shearer, Shane Heffernan, Mark Waldron, Melitta McNarry, Liam P. Kilduff

Journal Article

Objectives

To profile the distances covered during international women’s rugby union match-play and assess the duration-specific worst-case scenario locomotor demands over 60-s to 600-s epochs, whilst comparing the values determined by fixed epoch (FIXED) versus rolling average (ROLL) methods of worst-case scenario estimation and assessing positional influences.

Design

Descriptive, observational.

Methods

Twenty-nine international women’s rugby union players wore 10 Hz microelectromechanical systems during eight international matches (110 observations). Total, and per-half, distances were recorded, whilst relative total and high-speed (>4.4 m s−1) distances were averaged using FIXED and ROLL methods over 60–600-s. Linear mixed models compared distances covered between match halves, assessed FIXED versus ROLL, and examined the influence of playing position.

Results

Players covered ∼5.8 km match−1, with reduced distances in the second- versus first-half (p < 0.001). For worst-case scenario total (∼8–25%) and high-speed (∼10–26%) distance, FIXED underestimated ROLL. In ROLL, worst-case scenario relative total and high-speed distances reduced from ∼144−161 m min−1 and ∼30−69 m min−1 over 60-s, to ∼80 89 m min−1 and ∼5 16 m min−1 in the 600-s epoch, respectively. Forwards performed less high-speed running over all epochs and covered less total distance during epochs of 60-s, 180-s, 420-s and 480-s, compared with backs. Front row players typically returned the lowest locomotor demands.

Conclusions

This is the first study reporting the positional and worst-case scenario demands of international women’s rugby union, and indicates an underestimation in FIXED versus ROLL over 60-s to 600-s epochs. Knowledge of the most demanding periods of women’s rugby union match-play facilitates training specificity by enabling sessions to be tailored to such demands.

Incidence of Achilles tendinopathy and associated risk factors in recreational runners: A large prospective cohort study

02-01-2020 – Iris F. Lagas, Tryntsje Fokkema, Jan A.N. Verhaar, Sita M.A. Bierma-Zeinstra, Marienke van Middelkoop, Robert-Jan de Vos

Journal Article

Objectives

To determine the incidence of Achilles tendinopathy in a large group of recreational runners and to determine risk factors for developing AT.

Design

Observational cohort study.

Methods

Runners registering for running events (5–42 km) in the Netherlands were eligible for inclusion. Main inclusion criteria were: age ≥18 years, and registration ≥2 months before the running event. The digital baseline questionnaire obtained at registration consisted of demographics, training characteristics, previous participation in events, lifestyle and previous running-related injuries. All participants received 3 follow-up questionnaires up to 1 month after the running event with self-reported AT as primary outcome measure. To study the relationship between baseline variables and AT onset, multivariable logistic regression analyses were performed.

Results

In total, 2378 runners were included, of which 1929 completed ≥1 follow-up questionnaire, and 100 (5.2%, 95%CI 4.2;6.2) developed AT. Runners registered for a marathon (7.4%) had the highest incidence of AT. Risk factors for developing AT were use of a training schedule (odds ratio (OR) = 1.8 (95%Confidence Interval(CI)1.1;3.0)), use of sport compression socks ((OR = 1.7, 95%CI1.0;2.8) and AT in the previous 12 months (OR = 6.3, 95%CI3.9;10.0). None of the demographic, lifestyle or training-related factors were associated with the onset of AT.

Conclusion

One in twenty recreational runners develop AT. AT in the preceding 12 months is the strongest risk factor for having AT symptoms. Using a training schedule or sport compression socks increases the risk of developing AT and this should be discouraged in a comparable running population.

Trial registration number

The Netherlands Trial Register (ID number: NL5843).

Change and determinants of total and context specific sitting in adults: A 7-year longitudinal study

14-01-2020 – Heini Wennman, Tommi Härkänen, Maria Hagströmer, Pekka Jousilahti, Tiina Laatikainen, Tomi Mäki-Opas, Satu Männistö, Hanna Tolonen, Heli Valkeinen, Katja Borodulin

Journal Article

Objectives

To assess the stability and determinants of total and context specific sitting in a follow-up of adults.

Design

Longitudinal study.

Methods

Participants in the DILGOM cohort (n = 3735, men 45%), reported daily sitting in five contexts (work-related, in vehicle, at home by the TV, at home at the computer, and elsewhere) in 2007 and 2014. Sociodemographic background, lifestyle and health were assessed in 2007. Total sitting comprised the sum of context specific sitting. Changes in, and determinants of context specific sitting, stratified by baseline age into young middle-aged (<53 years); late middle-aged (53–68 years) and older-aged (>68 years) were estimated by generalized linear mixed models.

Results

In 2007, total daily sitting was 7 h 26 min, 6 h 16 min, and 6 h 3 min in young middle-aged, late middle-aged and older-aged groups, respectively. Over 7 years, total sitting decreased on average by 26 min. Sitting at the computer increased by 7–17 min. The late middle-aged group also increased sitting by the TV, and decreased total, work-related, vehicle and elsewhere sitting. Occupational status determined context specific sitting, but somewhat differently in young and late middle-aged groups. Poor self-rated health determined less work-related and more sitting by the TV in the young, whereas good health determined less work-related sitting in the late middle-aged group.

Conclusions

Self-reported sitting is a fairly stable behavior, with the exception for the late middle-aged group, where all context specific and total sitting changed significantly. Occupational status and health determined changes in sitting; however, somewhat differently by age group.

Relationship between meeting physical activity guidelines and motor competence among low-income school youth

11-01-2020 – Alessandro H. Nicolai Ré, Anthony D. Okely, Samuel W. Logan, Mellina M.L.M. da Silva, Maria T. Cattuzzo, David F. Stodden

Journal Article

Objectives

Global health guidelines suggest that youth should accumulate at least 60 min of daily, moderate-to-vigorous-intensity physical activity (MVPA). The relationship between meeting physical activity (PA) guidelines and motor competence (MC) in youth is relatively unknown. This study assessed levels of MVPA and MC among socially vulnerable youth and determined if meeting the PA guidelines was associated with MC.

Design

Cross-sectional.

Methods

A total of 1017 youths aged 3–14 years from three schools participated in the study. Participants wore accelerometers for seven consecutive days to assess PA. Motor competence was assessed using the Test of Gross Motor Development, 2nd Edition and the Körperkoordinationstest für Kinder. MVPA and MC were compared by sex and school levels (preschool, elementary school and middle school). Binary logistic regression models examined the predictive power of meeting PA guidelines and age on MC.

Results

The prevalence of meeting PA guidelines declined across school levels among both girls (72% in preschool to 21% in middle school, p < 0.001) and boys (84% in preschool to 57% in middle school, p < 0.001). MC levels were low and also declined across age in both sexes (p < 0.001). During preschool, age (older) was a consistent predictor of low MC, independently of meeting PA guidelines.

Conclusions

Except for adolescent boys, meeting PA guidelines was not associated with higher MC. Public health policies should focus on the quantity and quality of MVPA within schools and on alleviating the decline in PA and MC across childhood and adolescence, with special attention to girls and disadvantaged families.

Predictive modelling of the physical demands during training and competition in professional soccer players

11-01-2020 – J.V. Giménez, L. Jiménez-Linares, A.S. Leicht, M.A. Gómez

Journal Article

Objectives

The present study aimed to predict the cut-off point-values that best differentiate the physical demands of training and competition tasks including friendly matches (FM), small sided games (SSG), large sided games (LSG), mini-goal games (MG) and ball circuit-training (CT) in professional soccer players.

Design

Experimental randomized controlled trial.

Methods

Fourteen professional players participated in all tasks with the CT, SSG and MG consisting of 8 repetitions of 4-min game play, interspersed by 2-min of active recovery. The training data were compared to the first 32-min of the LSG and two competitive FM per player. All movement patterns from walking to sprint running were recorded using 10 Hz GPS devices while player perception of exertion was recorded via a visual analogue scale, post-task. Decision tree induction was applied to the dataset to assess the cut-off point-values from four training drills (SSG, LSG, MG, and CT) and FM for every parameter combination.

Results

Distance covered during jogging (2.3–3.3 m/s; >436 m), number of decelerations (≤730.5) and accelerations (≤663), and maximum velocity reached (>5.48 m/s) characterized the physical demands during competition (FM) with great variability amongst training drills.

Conclusion

The use of these novel, cut-off points may aid coaches in the design and use of training drills to accurately prepare athletes for soccer competition.

Differential recovery rates of fitness following U.S. Army Ranger training

25-12-2019 – William R. Conkright, Nicholas D. Barringer, Paula B. Lescure, Kimberly A. Feeney, Martha A. Smith, Bradley C. Nindl

Journal Article

Objectives

To investigate tactically-related physical performance and body composition recovery following U.
S. Army Ranger training.

Design

Prospective cohort.

Methods

Physical performance was comprehensively assessed using a tactically-related performance battery (i.e., Ranger Athlete Warrior assessment) in 10 male Soldiers at baseline (BL) two-weeks (P1), and six-weeks (P2) post-Ranger School. Body composition was determined using DXA. A one-way repeated measures ANOVA was used followed by Bonferroni-adjusted pairwise comparisons when group differences existed (p ≤ 0.05). Pearson correlation coefficients were used to establish associations between changes in fitness and body composition.

Results

All performance domains except the bench press and deadlift worsened following training. Speed/mobility (Illinois agility test, seconds – BL: 16.20 ± 0.86 vs. P2: 18.66 ± 2.09), anaerobic capacity (300-yard shuttle run, seconds – BL: 62.95 ± 6.17 vs. P2: 67.23 ± 5.91), core strength (heel clap, repetitions – BL: 15.80 ± 4.08 vs. P2: 11.50 ± 4.95), and aerobic endurance (beep test, stage – BL: 9.95 ± 2.18 vs. P2: 7.55 ± 1.07) had not recovered by P2. Only upper body muscular endurance and strength (metronome push-up and pull-up, respectively) were similar to BL by P2. Percent body fat increased from 15.62 ± 3.94 (BL) to 19.33 ± 2.99 (P2) (p < 0.001). There were no significant associations between changes in body composition and performance.

Conclusions

A comprehensive characterization of physical performance and body composition revealed Rangers did not experience full recovery of fitness six weeks after training. Optimal recovery strategies are needed to return Soldiers to a state of readiness following arduous training.

The effect of physical education lesson intensity and cognitive demand on subsequent learning behaviour

26-12-2019 – Christina H.H.M. Heemskerk, David Lubans, Steve Strand, Lars-Erik Malmberg

Journal Article

Objectives

To investigate the effect of (i) physical education (PE) lesson intensity and (ii) skill complexity, and (iii) their interaction on students’ on-task behaviour in the classroom.

Design

Within-subject repeated-measures.

Methods

Participants were children (N = 101, age 7–11) recruited from four elementary schools in Oxfordshire, United Kingdom. The experiment consisted of manipulating the aerobic intensity (low/medium/high) and skill complexity (low/high) of PE lessons. Children participated in all six conditions of the experiment: low intensity–low complexity (flexibility), medium intensity–low complexity (health related exercise), high intensity–low complexity (sprinting games), low intensity–high complexity (bi-lateral ball skills), medium intensity–high complexity (ball games), high intensity–high complexity (aerobics). Children’s behaviour in the classroom was observed every 30 s for 25 min before and after each PE lesson and rated as on-task or off-task.

Results

A main effect of intensity on children’s on-task behaviour was found (F(2,51634) = 11.07, p < 0.001), with greater on-task behaviour following high intensity PE lessons (thigh = 2.85, p < 0.01, d = 0.2). No main effect of complexity on on-task behaviour was observed (F(1,51636) = 1.89, p = 0.17). The interaction of intensity and complexity was significant (F(2,51628) = 69.19, p < 0.001).

Conclusions

These findings suggest that participation in PE lessons can improve children’s on-task behaviour in the classroom. PE lessons involving high complexity and high intensity, or low complexity and medium intensity appear to have the greatest benefits for students’ behaviour in the classroom.

Exercise-based injury prevention for community-level adolescent cricket pace bowlers: A cluster-randomised controlled trial

26-12-2019 – Mitchell R.L. Forrest, Jeffrey J. Hebert, Brendan R. Scott, Alasdair R. Dempsey

Journal Article

Objectives

To investigate if an exercise-based injury prevention program (IPP) can modify risk factors for injury in community-level adolescent cricket pace bowlers.

Design

Cluster-randomised controlled trial.

Methods

Eight cricket organisations (training two times per week and no previous involvement in a structured IPP) participated in this cluster-randomised trial. Participants were aged 14–17 years, injury free, and not currently performing a rehabilitation/exercise program. Cricket organisations (clusters) were block-randomised by computerised number generation into an intervention group (performed an eight-week IPP at training) or control group (continued their usual cricket activity). Participants were not blinded to group allocation. Strength, endurance, and neuromuscular control were assessed at baseline and follow-up. Treatment effects were estimated using linear mixed models.

Results

Sixty-five male adolescent pace bowlers (intervention n = 32 and control n = 33) were randomised. There were significant treatment effects favouring the intervention group for shoulder strength (90°/s) 0.05 (95% CI 0.02–0.09) N m/kg, hamstring strength (60°/s) 0.32 (95% CI 0.13–0.50) N m/kg, hip adductor strength dominant 0.40 (95% CI 0.26–0.55) N m/kg and non-dominant 0.33 (95% CI 0.20–0.47) N m/kg, SEBT reach distance dominant 3.80 (95% CI 1.63–6.04) percent of leg length (%LL) and non-dominant 3.60 (95% CI 1.43–5.78) %LL, and back endurance 20.4 (95% CI 4.80–36.0) seconds. No differences were observed for shoulder strength (180°/s) (p = 0.09), hamstring strength (180°/s) (p = 0.07), lumbopelvic stability (p = 0.90), and single leg squat knee valgus angle (dominant p = 0.06, non-dominant p = 0.15).

Conclusions

Exercise-based IPPs can modify risk factors for injury in community-level adolescent pace bowlers. Future research is needed to confirm if IPPs can also reduce injury risk in this population.

Athletic groin pain patients and healthy athletes demonstrate consistency in their movement strategy selection when performing multiple repetitions of a change of direction test

25-12-2019 – Adrian R. Rivadulla, Shane Gore, Ezio Preatoni, Chris Richter

Journal Article

Objectives

To report the consistency in movement strategy selection in athletic groin pain patients and to assess whether there are differences in consistency between athletic groin pain patients and healthy athletes.

Design

Cross sectional exploratory study.

Methods

Twenty athletic groin pain patients and 21 healthy athletes performed 15 repetitions of 110° change of direction task. Lower limb and trunk kinematics alongside ground reaction forces were collected. A correlation-to-mean algorithm was used to allocate each trial to a movement strategy using kinematic and kinetic features. Mann–Whitney U tests were used to compare the frequency of the most selected strategy (i.e. consistency) and fuzziness between athletic groin pain patients and healthy athletes. Chi-squared tests were used to compare the strategy selection between athletic groin pain patients and healthy athletes.

Results

There were no differences between groups in consistency in movement strategy selection (>80%). Athletic groin pain patients tended to select a knee dominant movement strategy whereas healthy athletes preferred an ankle dominant movement strategy.

Conclusions

The consistency observed in athletic groin pain patients supports the implementation of movement strategy assessments to inform AGP rehabilitation programmes tailored to athletes’ deficiencies. Such assessments could help enhance the success of athletic groin pain rehabilitation. Differences in movement strategy selection might not be associated with injury state since there were no differences between athletic groin pain patients and healthy athletes.

Can anthropometry and physical fitness testing explain physical activity levels in children and adolescents with obesity?

14-01-2020 – Ryan E.R. Reid, Alicia Fillon, David Thivel, Mélanie Henderson, Tracie A. Barnett, Jean-Luc Bigras, Marie-Eve Mathieu

Journal Article

Objectives

As time with patients and resources are increasingly limited, it is important to determine if clinical tests can provide further insight into real-world behaviors linked to clinical outcomes. The purpose of this study was to determine which aspects of anthropometry and physical fitness testing are associated with physical activity (PA) levels among youth with obesity.

Design

Cross-sectional study.

Method

Anthropometry height, waist circumference, bodyweight, fat percentage, physical fitness muscular endurance (partial curl-ups), flexibility (sit-and-reach), lower-body power (long-jump), upper-body strength (grip), speed/agility (5 × 5-m shuttle), cardiorespiratory fitness (VO2-max), and PA light (LPA), moderate (MPA), vigorous (VPA), MVPA was assessed in 203 youth with obesity.

Results

The sample was stratified by age <12 yrs (children); 12 yrs (adolescents) and sex. Stepwise regression evaluated associations between PA with anthropometry and physical fitness. Children (57% male) and adolescents (45% male) had a BMI Z-score of 3.5(SD:0.94) and 3.1(SD:0.76) respectively. Long-jump explained 19.5% (Standardized) Beta = 0.44; p = 0.001 of variance in VPA for childhood girls and 12.6% (Beta = 0.35; p = 0.025) of variance in MPA for adolescent boys. 5 × 5-m shuttle explained 8.4% (Beta = −0.29; p = 0.042) of variance in MVPA for childhood girls. Body mass explained 6.3% (Beta = −0.25; p = 0.007) of variance in LPA in childhood boys. Fat percentage explained 9.8% (Beta = 0.31; p = 0.03) of variance in MPA in adolescent girls.

Conclusions

In conclusion, tests of lower body power, body mass and fat percentage provide limited information concerning PA levels in youth with obesity. Activity monitoring should be considered in addition to clinical assessments to more fully understand youth health.

The plateau at V˙ O2max is associated with anaerobic alleles

12-01-2020 – Don R. Keiller, Dan A. Gordon

Journal Article

Objectives

This study tests the hypothesis that individuals who achieve a plateau at <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2max (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat) are more likely to possess alleles, associated with anaerobic capacity, than those who do not.

Design

A literature survey, physiological testing and genetic analysis was used to determine any association between the aerobic and anaerobic polymorphisms of 40 genes and <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat.

Methods

34, healthy, Caucasian volunteers, completed an exercise test to determine <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2max, and <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si2.svg” class=”math”> V˙ O2plat. 28 of the volunteers agreed to DNA testing and 26 were successfully genotyped. A literature search was used to determine whether the 40 polymorphisms analysed were associated with aerobic, or anaerobic exercise performance.

Results

The literature survey enabled classification of the 40 target alleles as aerobic 11, anaerobic 24, or having no apparent association (NAA) 5 with exercise performance. It also found no previous studies linking a genetic component with the ability to achieve <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat. Independent t-tests showed a significant difference (p < 0.001) in the ability to achieve <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat, but no other measured physiological variable was significantly different. Pearson’s χ2 testing demonstrated a highly significant association (p = 0.008) between anaerobic allele frequency and <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat, but not with <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2max. There was no association between aerobic alleles and <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat, or <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2max. Finally there were no significant differences in the allelic frequencies, observed in this study and those expected of Northern and Western European Caucasians.

Conclusion

These results support the hypothesis that the ability to achieve <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>V˙ O2plat is associated with alleles linked to anaerobic exercise capacity.

Determinants of hamstring fascicle length in professional rugby league athletes

14-01-2020 – Timothy M. McGrath, Billy T. Hulin, Nathan Pickworth, Alex Clarke, Ryan G. Timmins

Journal Article

Objectives

Investigate the determinants of hamstring fascicle length in professional rugby league players.

Design

Retrospective cohort study

Methods

Thirty-three elite male athletes underwent testing in the pre-season and in-season periods. Fascicle length measurements of the biceps femoris long head, 3D kinematics and elapsed time-periods at thigh angular velocities between 20 °/s to peak velocity during a single-leg Nordic hamstring strength test, GPS-derived running loads, age and previous injury history were all recorded. Fixed effect determinants for fascicle length were analyzed using multiple linear regression.

Results

Significant determinants of hamstring fascicle length were observed. Multivariate regression analysis showed modifiable factors including chronic (56 days) running volumes >80% of measured peak velocity and maximum velocity itself collectively explained 43% of the variability in the fascicle length data, whilst peak eccentric strength and elapsed time under load from 20 °/s to peak thigh angular velocity collectively contributed an additional 44%. Chronic running volumes >90% of individually measured peak velocity and the ‘break angle’ during a Nordic eccentric contraction were not significant contributors to the final model. Non-modifiable risk factors (age and previous injury) contributed the remaining 13%.

Conclusions

Managing high velocity running exposure as well as eccentric strength allows for ˜90% of the controllable determinants in fascicle length within elite athlete populations. An important contributor to the explained variability within fascicle length (superseded only by chronic velocity exposure and peak eccentric strength) was an athletes ability to achieve a prolonged contraction at long lengths during eccentric strength training rather than the angle of failure during the contraction in itself.

Acute performance responses during repeated matches in combat sports: A systematic review

18-12-2019 – Rafael L. Kons, Lucas B.R. Orssatto, Daniele Detanico

Journal Article, Review

Objective

Investigate the acute effects of repeated combat sports matches on vertical jump and handgrip strength performance in grappling and striking modalities.

Design

Systematic review.

Methods

PubMed, Scopus, and Web of Science databases were searched. The following eligibility criteria for selecting studies were adopted: Population: Combat sports athletes; Intervention: Official or simulated matches; Comparator: Baseline versus after-matches performance; Outcome: Vertical jump and/or handgrip strength performance. PROSPERO: CRD42019129264

Results

The systematic search resulted in 13 studies, including Brazilian jiu-jitsu, Greco-Roman, judo, taekwondo, and wrestling (freestyle and Greco-Roman) modalities, and a diverse number of repeated matches (i.e. 1–5). None of the studies adopted a randomized and controlled design and, consequently, none of them was classified as high quality. Brazilian jiu-jitsu and freestyle wrestling athletes presented an earlier onset of fatigue in upper and lower limbs, while judo and Greco Roman wrestling presented a later onset, from the third match. In taekwondo athletes, no fatigue was observed in the lower limbs, while handgrip strength decreased. However, studies have reported unclear data regarding the time-course of lower and upper limbs’ fatigue following repeated matches in taekwondo.

Conclusion

Both upper and lower limbs performance were affected after repeated matches in grappling combat sports when assessed by handgrip strength and vertical jump performance. In taekwondo, the studies have shown unclear results concerning the effects of repeated matches on upper and lower limb performance. There is a lack of studies classified as high-quality and investigations into the neuromuscular mechanisms underpinning fatigue after the repeated matches.

Changes in physical activity, sedentary behaviour and sleep across the transition from primary to secondary school: A systematic review

19-12-2019 – Kar Hau Chong, Anne-Maree Parrish, Dylan P. Cliff, Byron J. Kemp, Zhiguang Zhang, Anthony D. Okely

Journal Article, Review

Objectives

To describe how children’s time spent in the 24-h movement behaviours of physical activity (PA), sedentary behaviour (SB) and sleep change, individually and collectively, across the transition from primary to secondary school.

Design

Systematic review.

Methods

Six electronic databases were searched from January 1990 to May 2019. Eligibility criteria included longitudinal studies reporting time spent in PA, SB and/or sleep, with baseline assessments conducted during the last two years of primary school and at least one follow-up during the first two years of secondary school. For studies reporting only SB, this review considered those published from November 2015 onwards to update a previous systematic review.

Results

The present review identified six articles that reported changes in PA (n = 5) or PA and SB concurrently (n = 1). Most articles had a high risk of bias (n = 4/6). There was limited but consistent evidence of a change in PA over the school transition period; in particular a decrease in total daily PA and during specific time periods (i.e., in-school, after-school and leisure time). A concurrent but opposite change was observed in SB. No studies were identified that assessed changes in sleep, or all three movement behaviours concurrently.

Conclusions

Further research exploring concurrent changes in all movement behaviours (PA, SB and sleep) and associated factors is warranted to inform future behavioural interventions and policies for promoting an optimal 24 h movement behaviour pattern during this critical developmental period.