Journal of Science and Medicine in Sport

Journal of Science and Medicine in Sport

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.

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.

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.

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.

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.

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.

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.

Heat stress impairs proprioception but not running mechanics

25-08-2019 – Khouloud Mtibaa, Nidhal Zarrouk, Olivier Girard, Joong H. Ryu, Christophe Hautier, Sebastien Racinais

Journal Article

Objectives

To determine the effects of heat stress on ankle proprioception and running gait pattern.

Design

Counterbalanced repeated measures.

Methods

12 trained runners performed a proprioception test (active movement discrimination) before and immediately after a 30 min, self-paced treadmill run in HOT (39 °C) and COOL (22 °C) ambient conditions. Velocity was imposed during the first and last minute (70% of maximal aerobic velocity, 13.3 ± 0.8 km h−1) for determination of running mechanics and spring–mass characteristics.

Results

Rectal (39.7 ± 0.4 vs. 39.4 ± 0.4 °C), skin (36.3 ± 1.1 vs. 31.8 ± 1.1 °C) and average body (38.3 ± 0.2 vs. 36.4 ± 0.4 °C) temperatures together with heart rate (178 ± 8 vs. 174 ± 6 bpm) and thermal discomfort (6.5 ± 0.5 vs. 4.3 ± 1.3) were all higher at the end of the HOT compared to COOL run (all p < 0.05). Distance covered was lower in HOT than COOL (−5.1 ± 3.6%, p < 0.001). Average error during the proprioception test increased after running in HOT (+11%, p < 0.05) but not in COOL (−2%). There was no significant difference for most segmental and joint angles at heel contact, except for a global increase in pelvis retroversion and decrease in ankle dorsi-flexion angles with time (p < 0.05). Step frequency decreased (−2.5 ± 3.6%) and step length increased (+2.6 ± 3.8%) over time (p < 0.05), independently of condition. Spring–mass characteristics remained unchanged (all p > 0.05).

Conclusions

Heat stress exacerbates thermal, cardiovascular and perceptual responses, while running velocity was slower during a 30 min self-paced treadmill run. Heat stress also impairs ankle proprioception during an active movement discrimination task, but it has no influence on gait pattern assessed at a constant, sub-maximal velocity.

Identifying generalised segmental acceleration patterns that contribute to ground reaction force features across different running tasks

26-08-2019 – Jasper Verheul, John Warmenhoven, Paulo Lisboa, Warren Gregson, Jos Vanrenterghem, Mark A. Robinson

Journal Article

Objectives

To support future developments of field-based biomechanical load monitoring tools, this study aimed to identify generalised segmental acceleration patterns and their contribution to ground reaction forces (GRFs) across different running tasks.

Design

Exploratory experimental design.

Methods

A multivariate principal component analysis (PCA) was applied to a combination of segmental acceleration data from all body segments for 15 team-sport athletes performing accelerated, decelerated and constant low-, moderate- and high-speed running, and 90° cutting trials. Segmental acceleration profiles were then reconstructed from each principal component (PC) and used to calculate their specific GRF contributions.

Results

The first PC explained 48.57% of the acceleration variability for all body segments and was primarily related to the between-task differences in the overall magnitude of the GRF impulse. Magnitude and timing of high-frequency acceleration and GRF features (i.e. impact related characteristics) were primarily explained by the second PC (12.43%) and also revealed important between-task differences. The most important GRF characteristics were explained by the first five PCs, while PCs beyond that primarily contained small contributions to the overall GRF impulse.

Conclusions

These findings show that a multivariate PCA approach can reveal generalised acceleration patterns and specific segmental contributions to GRF features, but their relative importance for different running activities are task dependent. Using segmental acceleration to assess whole-body biomechanical loading generically across various movements may thus require task identification algorithms and/or advanced sensor or data fusion approaches.

A 2.5u202fmin cold water immersion improves prolonged intermittent sprint performance

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

Journal Article

Objectives

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

Design

Randomized-crossover design.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design & methods

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

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

Results

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

Conclusion

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

A systematic review of outdoor gym use: Current evidence and future directions

25-08-2019 – Anna K. Jansson, David R. Lubans, Jordan J. Smith, Mitch J. Duncan, Rebecca Haslam, Ronald C. Plotnikoff

Journal Article, Review

Objectives

While outdoor gyms are being rapidly installed around the globe, little is known about their implications on physical activity, and fitness and other health-related outcomes. The primary objective of this systematic review was to examine the effects of outdoor gyms on physical activity, fitness and other health-related outcomes. Secondary objectives were to describe outdoor gym characteristics, user characteristics, and outdoor gym usage.

Design

Systematic review.

Methods

Peer-reviewed papers published in English were obtained through online database searches of the following databases; EBSCO, SPORTdiscus, Medline, Psyc
INFO, Web of Science, Scopus and Informit. Searches covered the periods from database inception to January 2019. Studies that reported on the efficacy of outdoor gym use for physical activity, health-related outcomes or descriptive aspects of outdoor gyms and their users were eligible for inclusion.

Results

There was some support that outdoor gyms may improve physical activity, fitness and other health-related outcomes, however few experimental studies have been conducted. There was no consistency between outdoor gyms in terms types and number of installed equipment for each facility. Further, this review found discrepancies of whom were the most likely users of outdoor gyms and when they were mainly used.

Conclusions

This review contributes to the limited evidence on the impact and characteristics of outdoor gyms on physical activity and fitness and health-related outcomes.

Drivers of adolescent adiposity: Evidence from the Australian LOOK study

26-08-2019 – Richard D. Telford, Rohan M. Telford, Mary K. Martin, Marijke Welvaert

Journal Article

Objectives

To contribute to our understanding of the drivers of body composition during adolescence we sought to employ valid and reliable measures to investigate cross-sectional and longitudinal relationships between percentage body fat (%BF) and physical activity (PA), moderate and vigorous PA (MVPA), sedentary time (ST), total energy, sugar and fat intake.

Design

Longitudinal cohort study.

Methods

We measured 556 (289 male) participants at age 12.4 (SD 0.4) years, and 269 (123 males) at 16.3 (SD 0.4) years, for %BF (dual energy X-ray absorptiometry); habitual PA, MVPA, ST (accelerometry); and dietary intake (‘multi-pass’ weekday and weekend 24-h recall). Accounting for likely under-reporting of energy intake (Goldberg cut-off), general linear mixed modelling was used to generate relationships with %BF.

Results

Cross-sectional analyses indicated that 10 min more MVPA per day was associated with 0.6 lower %BF (95%CI 0.4–0.9, p < 0.001), and 10 min less ST/day with 0.07 lower %BF (95%CI 0.00–0.15, p < 0.001), independently of PA. In contrast, %BF was unrelated to total energy (p = 0.4), sugar intake (p = 0.2) or fat intake (p = 0.9). Longitudinal analysis showed that if PA was increased by 3% (10,000 counts/day) over the 4 years, then %BF was reduced by 0.08 (95%CI 0.05–0.12, p = 0.06).

Conclusions

The independent relationships of %BF with PA and ST, but absence of relationships with energy, sugar or fat intake, suggest that general community campaigns in a developed country directed at reducing adolescent obesity through modifications to energy intake and output would benefit from a more concerted focus on the latter.

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

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

Journal Article

Objectives

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

Design

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

Method

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

Panel study.

Methods

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

Results

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

Conclusions

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

Guidelines for community-based injury surveillance in rugby union

26-08-2019 – James C. Brown, Matthew Cross, Michael England, Caroline F. Finch, Gordon W. Fuller, Simon P.T. Kemp, Ken Quarrie, Martin Raftery, Keith Stokes, Ross Tucker, Evert Verhagen, Colin W. Fuller

Journal Article

Objectives

The vast majority of rugby union (‘rugby’) participants are community-based players; however, the majority of injury surveillance studies reported relate to the elite, professional game. A potential reason for this dearth of studies could be the perceived difficulty of using the consensus statement for injury recording at the community level. The aim of this study was to identify areas where the consensus statement could be adapted for easier and more appropriate implementation within the community setting.

Design

Round-table discussion.

Methods

All community-based injury surveillance issues were discussed during a 2-day facilitated round-table meeting, by an 11-person working group consisting of researchers currently active in rugby-related injury surveillance, sports medicine and sports science issues. The outcomes from the meeting were summarised in a draft guidance document that was then subjected to an extensive iterative review prior to producing methodological recommendations.

Results

Each aspect of the rugby-specific consensus statement was reviewed to determine whether it was feasible to implement the standards required in the context of non-elite rugby and the resources available within in a community setting. Final recommendations are presented within a community-based injury report form.

Conclusions

It is recommended that whenever possible the rugby-specific consensus statement for injury surveillance studies be used: this paper presents an adapted report form that can be used to record injury surveillance information in community rugby if suitable medical support is not available.

Prior history of anterior cruciate ligament (ACL) reconstruction is associated with a greater risk of subsequent ACL injury in female collegiate athletes

14-09-2019 – Jason Brumitt, Alma Mattocks, Amy Engilis, Dale Isaak, Jeremy Loew

Journal Article

Objectives

The risk of a subsequent anterior cruciate ligament (ACL) sprain is greater in high school aged female athletes with prior history of ACL reconstruction (ACLR) than in age-matched controls. The risk of a subsequent ACL injury in female collegiate athletes with prior ACLR is unknown. The primary purpose of this study was to determine the relative risk of a subsequent ACL injury in female collegiate athletes with prior ACLR when compared to age-matched controls. The secondary purpose of this study was to evaluate the ability of jump and hop tests to discriminate ACL injury risk.

Design

Prospective cohort.

Methods

Three hundred and sixty female collegiate athletes (mean age 19.3 ± 1.4 years) representing the following sports: volleyball, soccer, and basketball were recruited.

Subjects reported prior history of ACLR and standing long jump (SLJ) and single-leg hop (SLH) scores were collected during the preseason. Noncontact time-loss ACL and lower quadrant (i.e., low back and lower extremities) injuries were tracked by university athletic trainers.

Results

Female collegiate athletes with a prior history of ACLR were 6 times (RR = 6.8 95% CI: 1.4, 32.9 p-value = 0.007) more likely to experience an ACL injury than controls. Suboptimal performance on a battery of tests (SLJ ≤ 79% height, (B) SLH ≤ 69% height) was associated with a greater risk of lower quadrant injury (RR = 1.6 95% CI: 1.1, 2.4 p-value = 0.028); however performance on these tests was not associated with ACL injury.

Conclusions

Female collegiate athletes should be screened for history of ACLR.

Australian netball injuries in 2016: An overview of insurance data

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

Journal Article

Objectives

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

Design

An audit of insurance injury claims.

Methods

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

Results

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

Conclusions

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

Pectoralis major ruptures during rugby league tackling — Case series with implications for tackling technique instruction

23-09-2019 – Steve Sartori, Rod Whiteley

Journal Article

Objectives

Document the mechanism and incidence of pectoralis major ruptures in a professional rugby league cohort, and compare to any existing data.

Design

Retrospective case series.

Methods

Case series which documents 3 such injuries incurred while effecting a tackle in 3 rugby league players from the same squad (of 36) in the same season.

Results

At the initial point of contact, all three players were in a similar shoulder position of outer-range abduction and horizontal abduction and subsequently it appeared their pectoralis major was torn while attempting to effect the tackle.

Conclusions

Complete tears of the pectoralis major muscle are rare but significant injuries often requiring surgical intervention to restore full function in collision sport athletes. In this same season, the organisation changed their defensive approach which may have contributed to these injuries. Each player was managed with acute surgical repair and returned to play at the same level. Suggestions are made to consider the possible training injury implications of changing tackle technique.

Persistent vestibular-ocular impairment following concussion in adolescents

16-09-2019 – Aaron M. Sinnott, R.J. Elbin, Michael W. Collins, Valerie L. Reeves, Cyndi L. Holland, Anthony P. Kontos

Journal Article

Objectives

The current study investigated the role of persistent vestibular-ocular symptoms and impairment following sport-related concussion on recovery time and clinical outcomes among adolescents.

Design

Prospective cohort.

Methods

50 (F-22/M-28) adolescents aged 12–20 years completed a vestibular-ocular motor screening, neurocognitive assessment, and the Post-Concussion Symptom Scale (PCSS) at clinical assessments conducted at 0–10 and 11–21 days after concussion. Participants were assigned to: 1) persistent vestibular-ocular (PERSIST), 2) vestibular-ocular improvement (IMPROVE), or 3) no vestibular-ocular impairment (NONE) groups based on vestibular-ocular motor screening conducted during each assessment. A 3 (GROUP) X 2 (TIME) ANOVA was performed on neurocognitive and symptom scores, and a between-subjects ANOVA was performed for recovery time.

Results

49 subjects were identified among the PERSIST (n = 17), IMPROVE (n = 12) and NONE (n = 20) groups. There were no neurocognitive performance differences between groups at 0–10 days post-concussion, but groups differed on PCSS at 11–21 days (p = .001), with the PERSIST (29.0 ± 24.9) group reporting higher symptoms than the NONE (5.45 ± 10.0; p = .005) group. The PERSIST group took significantly longer to recover (34.9±11.6 days) than the NONE (22.9 ± 14.9 days) group (p = .03). All groups improved on verbal (p < .001) and visual memory (p = .028), visual motor speed (p = .005), and reaction time (p = .004) from 0–10 to 11–20 days following SRC and no significant group by time interactions for cognitive scores identified.

Conclusions

Persistent post-concussion vestibular-ocular symptoms and impairment may influence neurocognitive performance and clinical recovery following sport-related concussion.

Reliable sideline ocular-motor assessment following exercise in healthy student athletes

26-08-2019 – Vandana Sundaram, Victoria Y. Ding, Manisha Desai, Angela Lumba-Brown, Jessica Little

Journal Article

Objectives

To assess the reliability and effect of exercise on sideline dynamic visual performance measures of ocular-motor function using a portable visual assessment system (EYE-SYNC®).

Design

Prospective cohort study.

Methods

Healthy student athletes, ages 18–25 years, performed eye-tracking six times—three times consecutively prior to and after practice—using EYE-SYNC® goggles. Ocular-motor performance was assessed by calculating five gaze error outcomes between target position and actual gaze position to inform dynamic visual synchronization. We assessed reliability by calculating the intraclass correlation coefficient (ICC) for each outcome (we defined the standard deviation of tangential error (SDTE) as our primary outcome) and calculated differences in mean pre- and post-practice scores.

Results

ICCs for the SDTE score were 0.86 (95% confidence interval, CI: 0.82–0.9) and 0.88 (0.84–0.91) at pre- and post-practice, respectively. 133 (89%) and 135 (90%) of 150 athletes had at least one measurement at pre- and post-practice, respectively. 117 (78%) and 122 (81%) athletes had more than one SDTE score at pre- and post-practice, respectively. The absolute mean (SD) differences between pre- and post-practice mean scores ranged from 0.02 (0.05) for horizontal gain to 0.1 (0.5) for SDTE.

Conclusions

We observed high ICC scores indicating excellent reliability of visual synchronization measurements, suggesting that one measurement would be sufficient. Most athletes had similar scores before and after practice, indicating little change in visual performance following exercise. EYE-SYNC® goggles have the potential for use in obtaining objective visual performance measures of ocular-motor function for sideline assessment of concussion and return to play decisions.

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

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

Journal Article

Objectives

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

Design

Cross-sectional survey.

Methods

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

Results

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

Conclusions

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

Children’s fitness, fatness and sugar

05-11-2019 – Gordon S. Waddington

Editorial

Effects of acute aerobic and resistance exercise on executive function: An ERP study

26-08-2019 – Chih-Han Wu, Costas I. Karageorghis, Chun-Chih Wang, Chien-Heng Chu, Shih-Chun Kao, Tsung-Min Hung, Yu-Kai Chang

Journal Article

Objectives

This study addressed the effects of acute, moderate-intensity aerobic and resistance exercise on the shifting aspect of cognition following a 30-min recovery period. It also explored the neuro-electrical activation that underlies the relationship between acute exercise and cognitive function through the examination of P3b and N1 components of event-related potentials.

Design

A counterbalanced, repeated-measures experimental design.

Methods

Thirty-five volunteer young adults completed two experimental sessions (i.e., acute aerobic exercise (AE) and resistance exercise (RE), matched in terms of intensity, and one reading session (control). The AE entailed cycling at 60–70% of maximal heart rate reserve for 30 min. In the RE session, participants performed seven exercises with two sets of 8–12 repetitions at 70% of 10-repetition maximum. Each participants neuro-electrical activation was recorded 30 min after each session while s/he completed the task-switching test.

Results

After the 30-min recovery period, both AE and RE elicited shorter response times in global switching (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si2.gif” overflow=”scroll” class=”math”>ηp2=0.24) and local switching (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si3.gif” overflow=”scroll” class=”math”>ηp2=0.16) were observed when compared to control. Additionally, larger P3b amplitudes (but not N1 amplitudes) were evident in global switching (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si4.gif” overflow=”scroll” class=”math”>ηp2=0.15) and local switching (<math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si3.gif” overflow=”scroll” class=”math”>ηp2=0.16), regardless of exercise modality.

Conclusions

The present findings suggest that acute exercise has positive effects on cognitive function. Exercise-induced alterations during the later stages of mental processing might result in superior performance. There were significant selective benefits in terms of brain function regardless of exercise modality.

Association of sport participation in preterm and full term born children and body and fat mass indices from age 3 to 14 years

02-12-2019 – Juliane Spiegler, Marina Mendonça, Dieter Wolke

Journal Article

Objectives

To assess the association of gestational age groups (VP: <32 weeks, MP: 32–33 weeks, LP: 34–36 weeks and FT: ≥37 weeks of gestation) and club sport participation in childhood on body mass index (BMI), fat free mass index (FFMI) and fat mass index (FMI).

Design

Longitudinal, cross sectional.

Methods

BMI (age 3, 5, 7, 11 and 14 years; N = 10581–14702) and FFMI/FMI (age 7, 11 and 14 years; N = 10446–12996) and consistent club sport participation at age 5, 7 and 11 years (ranging from never participating to participating at all three ages) were assessed prospectively. These were compared by gestational age and their associations with BMI and FMI were investigated, while controlling for confounders (socio-economic, maternal obesity, child related, diet).

Results

BMI and FFMI was lower in VP or MP until age 7, but no differences were found in BMI, FFMI or FMI after age 11 with regard to gestational age. Consistent club sport participation from age 5–11 was unrelated to BMI at ages 3–7. However, FT children with club sport participation had lower BMI and FMI at ages 11 and 14; but this association was not found in VP or MP.

Conclusions

During adolescence body composition of VP and MP become similar to FT born peers. Consistent sport participation reduces BMI and FMI in FT only. In VP or MP children modifying effects of sport on body composition might not be detected due to the catch-up growth in weight, height and fat mass at the same time.

Clustering of screen time behaviours in adolescents and its association with waist circumference and cardiorespiratory fitness

27-11-2019 – Bruno G.G. da Costa, Jo Salmon, Priscila C. dos Santos, Giseli Minatto, Kelly S. Silva

Journal Article

Objectives

To identify the association of clusters of screen time (ST) behaviours with waist circumference (WC) and cardiorespiratory fitness (CRF) among adolescents.

Design

Cross-sectional study of 574 adolescents (53% girls, 13 years), conducted in 2017.

Methods

Waist circumference was measured, a shuttle run was performed to assess CRF, and a questionnaire was applied. Sex, age, socioeconomic status was reported, and daily duration of ST indicators for television viewing, computer use, videogame playing, and cellphone use, in weekdays and weekend days. Latent class analysis was performed to identify typologies of ST behaviours. Mixed-effects linear regressions were used to test the association of ST clusters with WC and CRF.

Results

Participants’ WC was 66.9 ± 8 cm and CRF was 39.5 ± 4 ml O2/kg/min. Four clusters were identified: “Low ST” (25%); “High ST” (20%); “Gamers” (17%); and “High cellphone” (39%). No significant associations were found between ST clusters and WC. Maximum oxygen uptake was higher in those in the “Low ST” cluster compared to the other clusters. No significant interactions for sex were observed.

Conclusions

Typologies of ST behaviours do not seem to be related to WC; however, those in the Low ST cluster had higher CRF compared to their peers in the other clusters, suggesting that total ST may be more important for CRF than specific indicators.

Physical activity types and motor skills in 3-5-year old children: National Youth Fitness Survey

27-11-2019 – Aaron P. Wood, Satomi Imai, Amy Gross McMillan, Damon Swift, Katrina D. DuBose

Journal Article

Objective

This study examined relationships between specific types of physical activity (PA) and motor skill development in preschool-aged children.

Design

This study was completed using a cross-sectional study design.

Methods

Data from children 3−5 years old (N = 342, 51% males) who participated in the 2012 National Youth Fitness Survey were analyzed. PA was measured using a questionnaire by parent report and motor skill development determined by Test of Gross Motor Development-2nd Edition (TGMD-2). Multiple regression analyses were conducted to examine the relationship between PA type and overall Gross Motor Quotient (GMQ) controlling for age, sex, race, and parental socioeconomic status.

Results

Commonly reported activities were running (43%), playing outdoor games (35%), and riding a bike (34%). Based on the standard scores, participants’ motor skill development for Locomotor, Object Control, and overall GMQ were considered average. Participation in the following physical activities were positively associated with GMQ: riding a bike (β (SE) = 5.27 (2.02), p = 0.02), scooter riding (β (SE) = 9.83 (2.59), p = 0.002), swimming (β (SE) = 4.01 (1.17), p = 0.004), and jumping on a trampoline (β (SE) = 7.45 (3.09), p = 0.03). With the exception of riding a bike, the physical activities positively related to GMQ had a reported range of participation between 7–12%.

Conclusions

Participation in specific physical activities was related to higher GMQ in preschool-aged children. Also, with the exception of riding a bike, the activities that the children participated in the most were not the same as the activities that were positively related to motor skill development.

Higher neck strength is associated with lower head acceleration during purposeful heading in soccer: A systematic review

30-11-2019 – Kerry Peek, James M. Elliott, Rhonda Orr

Journal Article, Review

Objective

To systematically review the literature to investigate the potential relationship between neck strength and head acceleration during purposeful heading in soccer.

Design

Systematic review.

Methods

Comprehensive search of five electronic databases: EMBASE, MEDLINE, CINAHL, Sports
Discus and Web of Science. Studies were included if they reported data on the relationship between neck strength and head impact and/or acceleration during purposeful soccer heading, published in English (or translation available).

Results

From an initial search of 1174 potentially eligible papers, five cross-sectional studies met the eligibility criteria for inclusion in this review. Data from cross-sectional studies indicate that higher neck strength is associated with lower head acceleration during purposeful heading in soccer (p = <0.05; r < −0.5).

Conclusion

This review provides evidence that higher neck strength may lower head acceleration during purposeful heading in soccer. Further research is required to determine the most effective method to strengthen the neck musculature in soccer players.

Unilateral jump landing neuromechanics of individuals with chronic ankle instability

01-12-2019 – Gabriel Moisan, Camille Mainville, Martin Descarreaux, Vincent Cantin

Journal Article

Objectives

To assess the neuromechanical (kinematic, kinetic and electromyographic (EMG)) differences between individuals with and without chronic ankle instability (CAI) during unilateral jump landing.

Design

Case-control study.

Methods

Kinematic, kinetic and EMG data of 32 participants with CAI and 31 control participants were collected during unilateral side jump landing (SIDE) and unilateral drop landing on three surfaces (even (DROP), unstable (FOAM) and laterally inclined (WEDGE)). Each participant had to complete five trials of each task in a randomised sequence. To compare the neuromechanical differences between groups, a one-dimensional statistical non-parametric mapping analysis was performed.

Results

Compared to the control group, the CAI group exhibited increased biceps femoris muscle activity during the preactivation and landing phases, decreased gluteus medius and peroneus longus muscles activity during the preactivation phase and increased knee extension moment during the landing phase of the WEDGE task. The CAI group also exhibited increased ankle dorsiflexion during the landing phase of the FOAM task and decreased vastus lateralis muscle activity during the preactivation phase of the DROP task. Finally, the CAI group exhibited decreased biceps femoris muscle activity during the preactivation and landing phases and decreased gluteus medius muscle activity during the preactivation phase of the SIDE task compared to the control group.

Conclusions

Individuals with CAI present neuromechanical differences during unilateral jump landing compared to healthy individuals. The results of this study will improve our understanding of underlying deficits associated with CAI and will help researchers and clinicians to better target them during rehabilitation.

Pronation or foot movement — What is important

30-11-2019 – Anja-Verena Behling, Sabina Manz, Vinzenz von Tscharner, Benno Maurus Nigg

Journal Article

Objectives

Despite difficulties to quantify foot pronation non-invasively and during dynamic tasks, pronation was frequently discussed with respect to injury risk and footwear development. Typically, surrogate measures were used to approximate the movement of pronation showing inconsistent results due to the high variability in the methodology and protocols. This study determines the relationships between all identified pronation variables and aims to reduce the data set to its dominant factors.

Design

Cross-sectional.

Methods

Forty barefoot participants (14 F, 26 M) performed four standing tasks (subneutral, bipedal, single-leg with 20° and single-leg with 30° knee flexion), over ground walking (1.5 m/s) and running (3.5 m/s) trials. Manual assessment data, motion capture data, ground reaction forces, and plantar pressure distributions were collected. Sixty-one commonly used pronation measures were compared using Spearman Correlations and a Principal Component Analysis (PCA).

Results

Two groups of correlated variables were found, 4.2% of them correlated mainly with the longitudinal arch angle (LAA), the other 10.2% correlated with the Achilles tendon angle (β). The remaining 85.6% were not significantly correlated to each other.

Conclusions

The LAA is representative for the movement of the mid foot and β quantifies rear foot eversion relative to the shank. Since these dominant variables varied independently from each other, both cannot quantify pronation simultaneously. Therefore, it is important to consider and report both, LAA-pronation and β-pronation separately to represent prevalent foot movement properties. Separately assessing the two dominant underlying mechanisms of foot movement may lead to improved guidelines for clinical screening and footwear manufacturing.

Variability within the human iNOS gene and Achilles tendon injuries: Evidence for a heterozygous advantage effect

26-11-2019 – Charlotte Brookes, William J. Ribbans, Louis Y. El Khoury, Stuart M. Raleigh

Journal Article

Objectives

The aim of this case control genetic association study was to explore whether two variants within the inducible nitric oxide synthase (i
NOS
) gene, rs2779249 (C/A) and rs2248814 (A/G), influenced the risk of Achilles tendinopathy in a British population.

Design

Candidate gene, case control association study.

Method

We recruited 145 individuals diagnosed with Achilles tendon pathology and 132 asymptomatic controls. All participants were genotyped for the i
NOS
variants using q
PCR and significant associations were discovered using a combination of Chi squared and ANOVA type analysis.

Results

The CA genotype of the i
NOS
rs2779249 variant was protective and conformed to a heterozygous advantage model of inheritance as it was overrepresented in the control participants (p = 0.009). In sex specific analysis the protective association persisted in male participants (p = 0.016) but not in females. Unlike the rs2779249 variant, the rs2248814 variant was not associated with Achilles tendinopathy or Achilles tendon rupture.

Conclusion

The rs2779249 CA genotype within the human i
NOS
gene appears to protect individuals from Achilles tendinopathy. This study further supports a genetic contribution to modifying the risk of Achilles tendon problems. The study also infers an important role for nitric oxide in tendon healing and/or degradation.

Health complaints and heat stress prevention strategies during taper as predictors of peaked athletic performance at the 2015 World Athletics Championship in hot conditions

26-11-2019 – Toomas Timpka, Julien D. Périard, Armin Spreco, Örjan Dahlström, Jenny Jacobsson, Victor Bargoria, Christer Andersson, Juan-Manuel Alonso, Sébastien Racinais

Journal Article

Objectives

To investigate whether self-reported health complaints and choice of heat stress prevention strategies during the taper predicted peaking at an athletics championship in hot conditions.

Design

Cohort study.

Methods

Data on health and heat stress prevention were collected before the 2015 World Athletics Championship in Beijing, China. Peaking was defined using the athlete’s pre-competition ranking and final competition rank. Baseline and endpoint data were fitted into multiple logic regression models.

Results

Two hundred forty-five (29%) of 841 eligible athletes participated. Both sprint/power (Odds ratio (OR) 0.33 (95% Confidence interval (CI) 0.11 to 0.94), P = 0.038) and endurance/combined events (OR 0.38 (95% CI 0.14 to 1.00), P = 0.049) athletes having sustained concern-causing health complaints during the taper were less likely to peak. Endurance/combined events athletes who chose pre-cooling to mitigate heat stress were less likely to peak (OR 0.35 (95% CI 0.15 to 0.80), P = 0.013), while sprint/power athletes reporting a sudden-onset injury complaint during the taper displayed increased peaking (OR 4.47 (95% CI 1.28 to 15.59), P = 0.019).

Conclusions

Health complaints that caused the athlete concern during the taper were predictive of failure to peak at a major athletics competition. Sprint/power athletes who experienced an acute injury symptom during the taper appeared to benefit from rest. Pre-cooling strategies seem to require further validation during real-world endurance/combined events. It appears that athletics athletes’ self-reported health should be monitored during the taper, concerns addressed, and heat stress prevention strategies individually tested before championships in hot conditions.

Intravenous fluids and their use in sport: A position statement from the Australian Institute of Sport

01-12-2019 – Samantha Pomroy, Greg Lovell, David Hughes, Nicole Vlahovich

Journal Article, Review

Objective

The use of intravenous fluids in out-of-hospital settings has evolved from the practices used by military and emergency response teams. When used in the elite sporting environment, IV fluid use must comply with the World Anti-Doping Code. Uncertainty can arise as clinicians seek to balance the appropriate use of IV fluids in delivering athlete care against the need for World Anti-Doping Code compliance.

Design and method

This position statement reviews the current literature and incorporates clinical experiences to present best-practice recommendations on the clinical use of Intravenous fluids in the elite sport environment, framing recommendations in the context of the World Anti-Doping Code.

Results and conclusion

The World Anti-Doping Code restricts the use of Intravenous fluids in athletes under certain conditions. This report takes into account the World Anti-Doping Code and the risks of Intravenous fluid administration to provide guidelines around the judicious use of IV fluids for:

1. Treatment of severe dehydration in an athlete,

2. Management of exertional heat illness in an athlete,

3. Hypovolaemia because of trauma in sport,

4. Administering medications.

Glenohumeral external rotation weakness partially accounts for increased humeral rotation torque in youth baseball pitchers

30-11-2019 – Kyle W. Wasserberger, Jeff W. Barfield, Jessica L. Downs, Gretchen D. Oliver

Journal Article

Objectives

To examine differences in shoulder internal rotation (IR) torque among youth pitchers of above and below average relative glenohumeral (GH) rotation strength levels. It was hypothesized that differences in IR torque during the pitching motion would could be explained by differences in relative IR and external rotation (ER) strength.

Design

Descriptive laboratory study.

Methods

Isometric GH rotation strength and upper extremity pitching mechanics were assessed in 78 male youth baseball pitchers (12.7 ± 2.0 yrs; 1.63 ± 14.0 m; 56.9 ± 12.4 kg). Shoulder IR torque during the pitch was examined at maximum humeral external rotation (MER) and throughout the arm acceleration phase (ACC). Multivariate analysis of covariance (MANCOVA) was used to examine the differences in pitching IR torque between GH strength groups.

Results

A significant main effect of ER strength on the dependent variables was present after controlling for fastball velocity (λ = 0.855, F2,72 = 6.13, p = 0.003, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>ηp2 = 0.145). Follow up univariate tests indicated significant differences in IR torque between strength groups at MER (F1,73 = 12.36, p < 0.001, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>ηp2 = 0.145) and during ACC (F1,73 = 6.65, p =  0.012, <math xmlns:mml="http://www.w3.org/1998/Math/Math
ML” altimg=”si1.svg” class=”math”>ηp2 = 0.083). Participants who displayed ER strength at or below the group mean experienced greater IR torque at MER and greater average IR torque during ACC than participants who displayed ER strength above the group mean.

Conclusions

Weakness of the GH ER musculature partially accounts for increased shoulder IR torque during pitching.

Validity of a novel device for real-time analysis of cyclists’ drag area

20-11-2019 – Pedro L. Valenzuela, Yago Alcalde, Jaime Gil-Cabrera, Eduardo Talavera, Alejandro Lucia, David Barranco-Gil

Journal Article

Objectives

To assess the reliability, validity, and sensitivity of a novel device (Notio Konect™) which is purported to provide a real-time analysis of aerodynamic drag area (Cd
A) during cycling.

Design

Observational, cross-sectional study.

Methods

Fifteen trained cyclists rode in an indoor velodrome using three different positions (upright, aero holding aero bars, and optimized aero similar to aero, but wearing a time-trial helmet). They completed six 1-min trials in each position. The Cd
A was measured with Notio and with two other systems (Track Aero System™ TAS and a validated mathematical model).

Results

The Cd
A measured with Notio showed good reliability (intra-class correlation coefficient ICC = 0.92, 90% confidence interval CI = 0.89–0.95). Notio showed an almost perfect relationship with both TAS (ICC = 0.99, 90% CI = 0.98–0.99) and the mathematical model (ICC = 0.99, 90% CI = 0.98–0.99). However, the Cd
A values provided by the former (0.308 ± 0.051 m2) were significantly higher (albeit with a trivial effect size ES) compared with TAS (0.300 ± 0.051 m2, p < 0.001, ES = 0.15) and the mathematical model (0.303 ± 0.051 m2, p = 0.005, ES = 0.09). The Cd
A was higher in the upright than in the aero position with all systems (all p < 0.001, ES = 1.84–1.89), and higher in the aero than in the optimized aero position when measured with TAS (p = 0.033, ES = 0.22) or the mathematical model (p = 0.024, ES = 0.24), but not with Notio (p = 0.220, ES = 0.19).

Conclusions

Notio appears to be reliable, strongly correlated to other established systems, and discerns large (upright vs aero) but not small (aero vs optimized aero) variations in riding position. Further research is needed to confirm its validity in outdoor conditions.

Sport participation, physical activity and sedentary behavior in the transition from middle school to high school

15-11-2019 – Emily R Shull, Marsha Dowda, Ruth P. Saunders, Kerry McIver, Russell R. Pate

Journal Article

Objectives

To examine associations between sport participation, and objectively assessed physical activity and sedentary behavior in youth during the transition from middle school to high school.

Design

Longitudinal study with 2-year follow-up.

Methods

Sport participation and accelerometer-measured physical activity and sedentary behavior were assessed in 306 children (122 males, 184 females) when they were in 7th and 9th grades (mean age of 12.5 ± 0.5 years).

Results

Sport participation and physical activity declined from 7th to 9th grade, but total physical activity (d = 0.38, p < 0.0001) and moderate-to-vigorous physical activity (d = 0.26, p = 0.0004) remained higher in sport participants compared to non-participants. In 9th grade, the full sample of sport participants compared to non-participants had higher levels of total physical activity (20.7 min/h vs. 18.5 min/h) and moderate-to-vigorous physical activity (1.8 min/h vs. 1.6 min/h). Sex-specific analysis revealed similar patterns in both females and males. Sedentary behavior remained lower (d = -0.37, p = <0.0001) in the full sample of sport participants compared to non-participants (39.8 min/h vs. 41.7 min/h) in 9th grade. Similar patterns were observed in both females and males.

Conclusions

Children’s participation in sport is associated with greater levels of physical activity and lower levels of sedentary behavior during the transition from middle school to high school. Promoting children’s participation in sports could be an effective public health strategy to help children meet the current physical activity guideline.

Psychological factors and future performance of football players: A systematic review with meta-analysis

23-11-2019 – Andreas Ivarsson, Amanda Kilhage-Persson, Russell Martindale, David Priestley, Barbara Huijgen, Clare Ardern, Alan McCall

Journal Article, Review

Objectives

This systematic review had 3 key objectives: (1) to investigate whether psychological factors were associated with future football performance (e.g., progression to professional football, better game statistics during the next season); (2) to critically review the methodological approaches used in the included studies and summarize the evidence for the current research question; (3) to provide guidelines for future studies.

Design

Systematic review.

Methods

Electronic databases (SPORTDiscus, PubMed and Psyc
INFO) and previously published systematic and scoping reviews were searched. Only prospective studies were considered for inclusion.

Results

Eleven published studies that reported 39 effect sizes were included. Psychological factors; task orientation, task-oriented coping strategies and perceptual-cognitive functions had small effects on future performance in football (ds = 0.20–0.29). Due to high risk of bias there were low certainty of evidence for psychological factors relationship with future football performance.

Conclusions

Psychological factors investigated showed small effects on future football performance, however, there was overall uncertainty in this evidence due to various sources of bias in the included studies. Therefore psychological factors cannot be used as a sole deciding factor in player recruitment, retention, release strategies, however it would appear appropriate to include these in the overall decision-making process. Future, studies with more appropriate and robust research designs are urgently needed to provide more certainty around their actual role.

Co-creation of a sport-specific anterior cruciate ligament injury risk reduction program for women: A concept mapping approach

18-11-2019 – A.M. Bruder, K.M. Crossley, A.B. Mosler, B. Patterson, M. Haberfield, A. Donaldson

Journal Article

Objectives

To engage physiotherapists experienced in female elite sport and athletes to co-create a sport-specific anterior cruciate ligament (ACL) injury risk reduction program.

Design

Concept Mapping.

Methods

The Concept Systems Global MAX™ web platform was used to collect and analyse data from 27 context and content experts (22 physiotherapists, 5 athletes). Participants brainstormed statements representing the critical elements that should be included in an ACL injury risk reduction program for women playing elite Australian Football (AF).

Results

Twenty-two participants brainstormed 56 statements that were synthesised and edited to 62 statements. Statements were sorted into clusters by twenty-three participants and rated on importance and feasibility using six-point scales. Multidimensional scaling and cluster analysis identified a 5-cluster solution as follows: Football-specific preparation (15 statements); Movement skills (17 statements); Strength and conditioning (15 statements); Individual preparation (7 statements); and Education (8 statements). Calculation of mean ratings for each cluster and statement identified the Movement skills cluster as most important (mean = 3.61 out of 5) and the Football-specific preparation cluster as most feasible (3.75 out of 5). By contrast, the Individual preparation cluster was rated the least important (mean = 2.9 out of 5), and the least feasible (3.12 out of 5), to include in the program.

Conclusions

The five clusters of critical elements to include in an ACL injury risk reduction program for women playing elite AF, in order of most to least importance were: movement skills, football-specific preparation, education, strength and conditioning and individual preparation.

Medical care in unlicensed combat sports: A need for standardised regulatory frameworks

11-11-2019 – Alex Channon, Christopher R. Matthews, Mathew Hillier

Journal Article

Objectives

To explore the provision of medical care at ‘unlicensed’, full-contact amateur and lower-level professional combat sports competitions in England.

Design

Qualitative, mixed methods.

Methods

Observations totalling 200 h of fieldwork shadowing medical professionals at 27 individual combat sports events, alongside formal, semi-structured interviews with 25 medical professionals, 7 referees and 9 promoters/event staff.

Results

Practices and standards vary widely. Event organisers and promoters often have very little understanding of how different types of medical practitioners operate. They rarely, if ever, check that the staff they are hiring are qualified, sometimes resulting in unqualified staff being used to provide medical cover at events. Venues are often poorly equipped to accommodate basic medical procedures. Patient confidentiality is very often compromised. Medical professionals often have limited autonomy within the combat sports milieu and may find themselves marginalised, with their judgements overruled by non-medical staff during competitive events. Some practitioners are cognisant of the dangers such working environments pose to their professional reputations and livelihoods, but remain working within combat sports regardless.

Conclusions

Despite pockets of good practice, the lack of standardised rules for medical care provision creates substantial risks to athletes, to practitioners and the standing of the profession. The development and implementation of standardised, enforceable regulatory frameworks for full-contact combat sports in England is urgently needed.

Oxford foot model kinematics in landings: A comparison between professional dancers and non-dancers

18-11-2019 – Ana M. Azevedo, Raúl Oliveira, João R. Vaz, Nelson Cortes

Journal Article

Objectives

Dancers frequently perform jump-landing activities, with the foot-ankle complex playing an essential role to attenuate the landing forces. However, scarce research has been conducted in professional dancers multi-segmented foot in landings. The aim of this study was to compare the multi-segmented foot kinematics between professional dancers and non-dancers, during forward and lateral single-leg jump-landings.

Design

Descriptive group comparison.

Methods

Marker trajectories and synchronized ground reaction forces of 15 professional dancers and 15 non-dancers were collected using motion capture and a force plate, during multidirectional single-leg jump-landings. Sagittal and frontal hindfoot-tibia, forefoot-hindfoot, and hallux-forefoot kinematics of the multi-segmented foot model were computed at initial contact, peak vertical ground reaction force and peak knee flexion. Repeated measures ANOVAs were conducted (p < 0.05).

Results

Professional dancers landed with higher hindfoot-tibia and forefoot-hindfoot plantarflexion angles at initial contact (p < 0.001), and hindfoot-tibia dorsiflexion angles at peak vertical ground reaction force and peak knee flexion (p < 0.001) than non-dancers. Also, dancers exhibited higher sagittal hindfoot-tibia and forefoot-hindfoot excursions than non-dancers (p < 0.001). No statistically significant differences were found in the frontal plane.

Conclusions

The multi-segmented foot allows a comprehensive kinematic analysis of the different foot joints. In jump-landings, professional dancers higher hindfoot-tibia, and forefoot-hindfoot plantarflexion at initial contact, compared to non-dancers, contributed to a subsequent higher foot joints excursion. This pattern is commonly linked to a better shock absorption mechanism in landings.

Characterisation of Achilles tendon pain in recreational runners using multidimensional pain scales

14-11-2019 – Nonhlanhla S. Mkumbuzi, Alison V. September, Michael Posthumus, Brenda Oulo, Trevor S. Mafu, Malcolm Collins

Journal Article

Objectives

The main assessment tool for Achilles tendinopathy (AT) is the VISA-A. However, the VISA-A only assesses the physical impairments that result from tendon pain. This study sought to describe and assess tendon pain using other multidimensional pain scales; the short forms of the McGill pain questionnaire (sf-MPQ) and the Brief Pain Inventory (sf-BPI).

Design

Cross sectional observational study.

Methods

124 recreational runners with clinically confirmed mid-portion Achilles tendinopathy for at least 3 months were recruited from Cape Town, South Africa. They described and rated their tendinopathy symptoms by completing the VISA-A, sf-BPI and sf-MPQ questionnaires.

Results

Tendon pain was largely described as a sensory type of pain with minimal affective elements. Sixty percent described their pain as aching. Significant proportions described it as tender (52.9%), throbbing (33.9%), hot burning (24.8%) and 33.8% ranked it as discomfiting or worse on the pain intensity score of the sf-MPQ. Tendon pain interfered with mood in 50.8% of the participants as well as with walking ability (72.5%), sleep (34.8%) and enjoyment of life (54.2%).

Conclusions

Tendon pain was described using a variety of adjectives which may suggest that AT has clinical subtypes. Tendon pain interferes with more than just physical function. Therefore, the recommendation is to conduct further studies using various pain questionnaires to elicit more details and better understand the nature of Achilles tendon pain.

Acute aerobic exercise and neuroplasticity of the motor cortex: A systematic review

25-11-2019 – Maddison L. Mellow, Mitchell R. Goldsworthy, Scott Coussens, Ashleigh E. Smith

Journal Article, Review

Objectives

To synthesise the existing literature investigating if acute aerobic exercise enhances the response to experimentally-induced neuroplasticity paradigms.

Methods

A systematic search of electronic databases Medline, Psyc
Info and Embase was undertaken on 26 April 2018 and updated on 17 May 2019. Studies were included if they involved a bout of aerobic exercise; prescribed a bout of rest as a control condition; utilized a non-invasive brain stimulation paradigm to induce neuroplasticity; used TMS to assess neuroplasticity outcomes; participants were healthy 18–65 year old males and females with no diagnosed neurological/psychological impairments.

Results

Eight papers (containing 12 experiments) met inclusion criteria. All studies utilized cycling or treadmill exercise as their exercise modality, and exercise intensity ranged from low intensity continuous exercise to high-intensity interval exercise. Four neuroplasticity paradigms were employed including paired associative stimulation (PAS) (n = 3), continuous theta-burst stimulation (c
TBS) (n = 2), intermittent theta-burst stimulation (i
TBS) (n = 2) and transcranial direct current stimulation (n = 1). Aerobic exercise enhanced neuroplastic responses (compared to rest) in seven of the 12 experiments.

Conclusions

This review provides emerging evidence that acute aerobic exercise can enhance the response to experimentally-induced neuroplasticity paradigms. However, there remains great variability in the study design and reporting of effects in these studies and thus a more standardized approach is encouraged to better understand the relationship between acute aerobic exercise and neuroplasticity. Future studies should consider optimizing intensity, paradigms and duration of both exercise and neuroplasticity paradigms employed.

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.

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.

Perceived exertion responses to wheelchair propulsion differ between novice able-bodied and trained wheelchair sportspeople

11-11-2019 – Michael J. Hutchinson, Jonathan W. Kilgallon, Christof A. Leicht, Victoria L. Goosey-Tolfrey

Journal Article

Objectives

To investigate peripheral (RPEP) and central (RPEC) Ratings of Perceived Exertion during wheelchair propulsion in untrained able-bodied (AB) participants, and trained wheelchair rugby athletes with and without cervical spinal cord injury (CSCI).

Design

Cross-sectional study.

Methods

38 participants (AB: n = 20; wheelchair rugby athletes with CSCI: n = 9; without CSCI: n = 9) completed an incremental wheelchair propulsion test to exhaustion on a motorised treadmill. Gas exchange measures and heart rate (HR) were collected throughout. RPEP and RPEC on the Category Ratio-10 were verbally recorded each minute. Blood lactate concentration (BLa) was determined post-test.

Results

Between 50–100% peak oxygen uptake (V̇O2peak), RPEP was greater than RPEC in AB (p < 0.05), but not in athletes with (p = 0.07) or without (p = 0.16) CSCI. RPEP was greater in AB compared to players with CSCI (Effect sizes: 1.24–1.62), as were respiratory exchange ratio (1.02 ± 0.10 vs 0.82 ± 0.11, p < 0.05) and BLapeak (7.98 ± 2.53 vs 4.66 ± 1.57 mmol·L−1). RPEC was greater in athletes without CSCI compared to those with CSCI (Effect sizes: 0.70–1.38), as were HR (166 ± 20 vs 104 ± 15 beats·min−1, p < 0.05) and ventilation (59.2 ± 28.8 vs 35.1 ± 16.6 L·min−1, p = 0.01).

Conclusions

RPEP was dominant over RPEC during wheelchair propulsion for untrained AB participants. For athletes with CSCI, lower RPEP and RPEC were reported at the same %V̇O2peak compared to those without CSCI. The mechanism for this remains to be fully elucidated.

The effect of parental logistic support on physical activity in children with, or at risk of, movement difficulties

14-11-2019 – Kemi E. Wright, Bonnie J. Furzer, Melissa K. Licari, James A. Dimmock, Ben Jackson

Journal Article

Objectives

In a sample of children with, or at risk of, movement difficulties, (1) To test the direct effects of children’s perceptions of parents’ logistic support for physical activity on children’s physical activity-related self-perceptions and on children’s physical activity levels, and (2) To explore the indirect relationship between children’s perceptions of parents’ logistic support for physical activity and children’s physical activity levels through children’s physical activity-related self-perceptions.

Design

Cross-sectional observation study.

Methods

Data were collected from 120 children aged 6 to 12 years; movement proficiency levels were determined using the movement assessment battery for children-2 test. Children’s perspectives of parental support for physical activity were captured using the Activity Support Scale for Multiple Groups child report. Children’s self-perceptions towards physical activity were reported with the Children’s Self- perceptions of Adequacy in and Predilections for physical activity, and time spent in physical activity were measured using accelerometers.

Results

There was no significant direct effect between perceived levels of parents’ logistic support for physical activity and children’s physical activity. A significant indirect relationship between these variables was discovered, with higher perceived levels of parent logistical support for physical activity predicting stronger perceptions of adequacy (i.e., confidence) toward physical activity participation among children, which in turn was associated with increased physical activity minutes.

Conclusions

The results demonstrate that irrespective of a child’s movement ability, children’s perceptions of parents’ logistic support for physical activity indirectly and positively predicts children’s physical activity levels, via children’s confidence for physical activity.

Performance indicators during international rugby union matches are influenced by a combination of physiological and contextual variables

11-11-2019 – Blair T. Crewther, Neill Potts, Liam P. Kilduff, Scott Drawer, Christian J. Cook

Journal Article

Objectives

Research has linked physiological (e.g., hormonal, affective, fatigue) outcomes to performance indicators in rugby competition, but no work has integrated and contextualised these factors within a test-match environment. We addressed this gap by monitoring 29 athletes from a training squad across eight international rugby matches.

Design

Longitudinal observational study.

Methods

Pre-match (8–9 am) measures of salivary testosterone and cortisol concentrations, sleep duration, pulse rate, muscle soreness, stress, mood, and motivation were taken. Contextual factors were playing time, internal training load (ITL), test-match experience, opponent ranking, and crowd size. Performance was indexed by coach and player ratings of performance (CRP, PRP) and quantitative metrics; offloads, turnovers, runs with ball in hand (RWB), tackles, passes, and defenders beaten (DFB).

Results

Morning cortisol, sleep and mood were positively related to CRP and PRP (standardised coefficient estimates from 0.17 to 0.22). Cortisol, sleep, stress, mood and motivation were associated with one (or more) of turnovers, RWB, tackles, passes and DFB (incidence rate ratio IRR from 0.74 to 1.40). Playing time was positively related to all quantitative performance indicators (IRR from 1.01 to 1.04) with ITL, opponent ranking, and crowd size predicting selected outputs (IRR from 0.89 to 1.15). The explanatory models varied (conditional R2 = 0.15–0.83) but were generally stronger with both physiological and contextual inputs.

Conclusions

Multiple physiological and contextual factors appear to contribute to player performance in international rugby competition. Measurement of these factors may guide training and management practices, a potential practical consequence but also advancing understanding from marker to causal link.

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.

Evaluation of school-based interventions of active breaks in primary schools: A systematic review and meta-analysis

15-11-2019 – Alice Masini, Sofia Marini, Davide Gori, Erica Leoni, Andrea Rochira, Laura Dallolio

Journal Article, Review

Objectives

To provide a systematic review of studies that investigated the effects of Active Break (AB) school-based interventions on Physical Activity (PA) levels, classroom behavior, cognitive functions, and academic performance in primary school children.

Design

Systematic review and meta-analysis.

Methods

Searches of electronic databases and grey literature, with no time restriction and up to April 2019, resulted in 22 intervention studies meeting the inclusion criteria. Quality assessment of the studies was performed in accordance with the Cochrane Tool for Quality Assessment for RCTs and the STROBE tool for observational studies.

Results

Four AB related outcomes were analyzed: (i) AB interventions had a significant effect in increasing PA levels in primary school children, both in terms of increased moderate to vigorous PA and step count. The meta-analysis seems to confirm this trend, showing a statistically significant result for the step count (p < 0.00001, CI95% −0.71,1.21) (random model I² = 0%). (ii) Regarding classroom behavior, time spent on task (TOT) during lessons significantly increased in each of the included studies. On the other hand, the effects on (iii) cognitive functions (attention components, working memory, executive functions) and (iv) academic achievements (mathematics, reading) were not conclusive.

Conclusions

Positive effects were found for PA levels and classroom behavior, while the conflicting results for cognitive functions and academic achievements suggest that the effect could be more evident with curriculum focused active breaks and active lessons that integrate ABs with key learning aspects and cognitive engagement.