Journal of Science and Medicine in Sport

The impact of exercise modality and menstrual cycle phase on circulating cardiac troponin T

07-11-2019 – Jinlei Nie, Haifeng Zhang, Zhaowei Kong, Cong Wang, Yang Liu, Qingde Shi, Keith George

Journal Article

Objectives

It is unclear whether exercise modality (moderate-intensity continuous MCE; high-intensity interval HIE) and menstrual cycle phase (follicular FP; luteal LP), individually or in combination, mediate the commonly observed exercise-induced elevation in cardiac troponin T (c
Tn
T). This study examines c
Tn
T responses to MCE and HIE during both the FP and LP.

Design

Randomised crossover study.

Methods

Seventeen healthy, eumenorrheic women completed four trials including MCE (60% VO2max steady-state cycling until 300 k
J) and work‐equivalent HIE (repeated 4-min cycling at 90% VO2max interspersed with 3-min rest) during both the FP and LP. The FP and LP were verified based on ovarian hormones. Serum c
Tn
T was assessed using a high-sensitivity assay before, immediately after, and 1 (1HR), 3 (3HR) and 4 (4HR) hours after exercise. c
Tn
T values were corrected for plasma volume changes.

Results

c
Tn
T was significantly elevated (p < 0.05) post-exercise in both MCE (at 3HR and 4HR) and HIE (at 1HR, 3HR and 4HR). No statistically significant difference (p > 0.05) in peak post-exercise c
Tn
T, which mostly occurred at 3HR, was seen among the four trials (median range, ng l−1: 5.2 1.7–18.1 after MCE during FP; 4.8 1.7–24.9 after MCE during LP, 8.2 3.9–24.8 after HIE during FP and 6.9 1.7–23.1 after HIE during LP).

Conclusions

A single 300 k
J bout of both MCE or HIE resulted in a significant post-exercise increase in c
Tn
T, with no differences in peak c
Tn
T response between menstrual cycle phases or between exercise modes, but the c
Tn
T elevation occurs slightly earlier after HIE.

Movement patterns of players in the Australian Women’s Rugby League team during international competition

11-11-2019 – K. Quinn, T. Newans, S. Buxton, T. Thomson, R. Tyler, C. Minahan

Journal Article

Objectives

To describe the movement patterns of the Australian Women’s Rugby League team during international competition.

Design

Retrospective observational study.

Methods

Global Positioning Systems technology recorded the movements of players from the Australian Women’s Rugby League team (n = 31) during seven international rugby league matches. A subgroup of players (n = 18) that played at least 80 min in a match were categorized into three positional groups: forwards (n = 7), backs (n = 7) and halves (n = 4), and analysed for external outputs that were classified into multiple speed zones. Mean speed (m min−1) and mean speed when travelling >12 km h−1 (MS12; m min−1) were calculated for each 10% interval of playing time of both groups to assess changes in match intensity.

Results

Total distance travelled was greater in the first half (3332.9 m compared to 3249.0 m), along with distances travelled at speeds >15 km h−1 (p < 0.05), whereas players travelled further at speeds <6 km h−1 in the second half (p = 0.005). Backs travelled further at speeds <6 km h−1 (p = 0.002) and >15 km h−1 (p = 0.007) compared to forwards. Mean speed significantly reduced across the first and second halves (p < 0.05), while MS12 reduced by ∼40% in the first half of the match (i.e. first ∼5 min compared to the last ∼5 min).

Conclusion

These results provide coaches with sport-specific activity profiles of female rugby league players that can be used to individualise training prescription. Given that match-intensity deteriorated across the first and second halves, programs may be targeted at improving endurance and supramaximal exercise tolerance in order for female players to withstand high match-demands of international competition.

Prevalence and application of priming exercise in high performance sport

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

Journal Article

Objectives

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

Design

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

Methods

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

Results

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

Conclusions

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

Using cooperative networks to analyse behaviour in professional Australian Football

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

Journal Article

Objectives

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

Design

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

Methods

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

Results

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

Conclusions

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

Feasibility and effect of a physical activity counselling session with or without provision of an activity tracker on maintenance of physical activity in women with breast cancer — A randomised controlled trial

24-10-2019 – Ben Singh, Rosalind R. Spence, Carolina X. Sandler, Jodie Tanner, Sandra C. Hayes

Journal Article

Objectives

The SAFE-Maintain study sought to evaluate the effect and acceptability of a physical activity counselling (PAC) session, versus a PAC session plus provision of a Fitbit (Charge HR®; PAC + F), on maintenance of physical activity levels 12 weeks following participation in a supervised exercise intervention.

Design

Fifty-two women with stage II + breast cancer who had recently (within the previous 7 days) completed a 12-week supervised exercise program were randomised to the PAC or PAC + F group.

Methods

Physical activity levels, including weekly minutes of total physical activity (min/week), daily step count (steps/day), and weekly minutes of moderate to vigorous physical activity (MVPA, min/week), were assessed using the Active Australia survey and Actigraph® GT3X+ accelerometers. Self-reported outcomes were assessed at baseline and 12-week follow-up, while objectively-measured outcomes were only available at 12-week follow-up.

Results

Compared with the PAC group, the PAC + F group had higher self-reported MVPA and self-reported total activity (between-group mean difference: 78.2 95% CI = −8.3, 164.9 min/week, p < 0.01, and 171.9 95% CI = 46.1, 297.8 min/week, p < 0.01, respectively) at 12-week follow-up. Higher objectively-assessed MVPA (p = 0.03) and steps/day (p = 0.07) at 12-week follow-up was also observed in the PAC + F group compared with the PAC group. Most (>80%) of the PAC + F group reported high levels of Fitbit use and considered the device to be beneficial for physical activity maintenance.

Conclusions

Findings suggest that activity trackers show promise as an effective, feasible and acceptable approach to support physical activity maintenance following completion of a supervised exercise intervention.

Trial registration

Prospectively registered on the Australian and New Zealand Clinical Trials Registry (ANZCTR, Trial registration number: ACTRN12616000954426).

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

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

Journal Article

Objectives

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

Design

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

Method

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

Longitudinal study.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

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

Methods

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

Results

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

Conclusions

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

Trial registration

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

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.

General health complaints and sleep associated with new injury within an endurance sporting population: A prospective study

22-12-2019 – R. Johnston, R. Cahalan, L. Bonnett, M. Maguire, P. Glasgow, S. Madigan, K. O’Sullivan, T. Comyns

Journal Article

Objectives

To examine the association between subjective health complaints, sleep quantity and new injury within an endurance sport population.

Design

Prospective cohort study.

Methods

Ninety-five endurance sporting participants were recruited from running, triathlon, swimming, cycling and rowing disciplines. Over 52-week period participants submitted weekly data regarding subjective health complaints (SHCs) (cardiorespiratory, gastrointestinal and psychological/lifestyle), sleep quantity, training load and new injury episodes. Applying a 7- and 14-day lag period, a shared frailty model was used to explore new injury risk associations with total SHCs and sleep quantity.

Results

92.6% of 95 participants completed all 52 weeks of data submission and the remainder of the participants completed ≥30 weeks. Seven-day lag psychological/lifestyle SHCs were significantly associated with new injury risk (Hazard ratio (HR) = 1.32; CI 95% = 1.01–1.72, p < 0.04). In contrast, cardiorespiratory (HR = 1.15; CI 95% = 0.99–1.36, p = 0.07) and gastrointestinal (HR = 0.77; CI 95% = 0.56–1.05, p = 0.09) SHCs were not significantly associated with new injury risk. New injury risk had a significant increased association with 14-day lag <7 h/day sleep quantity (HR = 1.51; CI 95% = 2.02–1.13, p < 0.01) and a significant decreased association with >7 h/day sleep quantity (HR = 0.63, CI 95% = 0.45–0.87, p < 0.01. A secondary regression analysis demonstrated no significant association with total SHCs and training load factors (Relative Risk (RR) = 0.08, CI 95% = 0.04–0.21, p = 0.20).

Conclusions

To minimise an increased risk of new injuries within an endurance sporting population, this study demonstrates that psychological/lifestyle subjective health complaints and sleep quantity should be considered. The study also highlights a lag period between low sleep quantity and its subsequent impact on new injury risk. No association was demonstrated between subjective health complaints, sleep quantity and training load factors.

Risk of acute and overuse injuries in youth elite soccer players: Body size and growth matter

07-11-2019 – Nikki Rommers, Roland Rössler, Lennert Goossens, Roel Vaeyens, Matthieu Lenoir, Erik Witvrouw, Eva D’Hondt

Journal Article

Objectives

This study investigated anthropometric measures and growth as risk factors for overuse and acute injuries in younger (U10–U12) and older (U13–U15) elite level soccer players.

Design

Prospective cohort study.

Methods

Height, weight, and sitting height were measured at the start and the end of the 2016–2017 competitive season and growth velocities were calculated. Throughout the season, injuries were registered continuously by the (para-)medical staff of the included clubs. We analyzed the injury risk using multilevel Poisson regression models, accounting for club and team clustering.

Results

Of the included 314 players (11.7 ± 1.7 years of age), 160 players sustained 133 overuse and 163 acute injuries (i.e. 106 injuries in 69 players of the younger group, 190 in 91 players of the older group). In the younger group, risk of overuse injuries was associated with an increase in leg length over the season (incidence rate ratio (IRR) 1.620 95% CI 1.230–2.117) and risk of acute injuries with relatively younger age (IRR 1.003 95% CI 1.000–1.006). In the older group, a higher leg length was associated with an increased risk of overuse injuries (IRR 1.055 95% CI 1.011–1.108), and a higher weight and a lower growth rate with an increased risk of acute injuries (IRR 1.043 95% CI 1.021–1.067 and 0.903 95% CI 0.831–0.981, respectively).

Conclusions

Injury risk factors differ by age group and type of injury. The age-specific anthropometric and growth-related risk factors should be monitored and these risk profiles should be considered to manage injury risk effectively.

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.

Proposed injury thresholds for concussion in equestrian sports

07-11-2019 – J. Michio Clark, Kevin Adanty, Andrew Post, T. Blaine Hoshizaki, Jonathan Clissold, Adrian McGoldrick, Jerry Hill, Aisling Ni Annaidh, Michael D. Gilchrist

Journal Article

Objectives

Equestrian helmets are designed to pass certification standards based on linear drop tests onto rigid steel surfaces. However, concussions in equestrian sports occur most commonly when a rider is thrown off a horse and obliquely impacts a compliant surface such as turf or sand. This paper seeks to elucidate the mechanics of such impacts and thereby propose corresponding thresholds for the occurrence of concussion that can improve equestrian helmet standards and designs.

Design

The present study examined the biomechanics of real-world equestrian accidents and developed thresholds for the occurrence of concussive injury.

Methods

Twenty-five concussive and 25 non-concussive falls in equestrian sports were reconstructed using a combination of video analysis, computational and physical reconstruction methods. These represented male and female accidents from horse racing and the cross-country phase of eventing.

Results

The resulting thresholds for concussion 59 g, 2700 rad/s2, 28 rad/s, 0.24 (MPS), 6.6 k
Pa and 0.27 (CSMD10) for 50% risk were consistent with those reported in the literature and represent a unique combination of head kinematic thresholds compared to other sports. Current equestrian helmet standards commonly use a threshold of 250 g and a linear drop to a steel anvil resulting in less than 15 ms impacts. This investigation found that concussive equestrian accidents occurred from oblique impacts to turf or sand with lower magnitude and longer duration impacts (<130 g and >20 ms). This suggests that current equestrian helmet standards may not adequately represent real-world concussive impact conditions and, consequently, there is an urgent need to assess the protective capacity of equestrian helmets under real-world conditions.

A prospective study of health problems at the 2018 17/U and 19/U Australian National Netball Championships with comparison of surveillance methodology

11-11-2019 – Erin A. Smyth, Laura Piromalli, Alanna Antcliff, Phillip Newman, Gordon Waddington, Juanita R. Weissensteiner, Michael K. Drew

Journal Article

Objective

To investigate the incidence, site, nature and cause of injuries sustained during and four weeks following the 2018 Australian National Netball Championships (ANNC’s) using medical attention and self-report surveillance tools.

Design

Prospective cohort study.

Method

Injuries were recorded prospectively using medical attention and self-report data collection methods. One hundred and ninety-two athletes competed at the 2018 ANNC’s with 96 athletes in each age group (17/U & 19/U).

Results

There were 103 medical attention injuries sustained by 80 athletes resulting in an incidence rate of 89.4 per 1000 player hours. The most frequently recorded medical attention injury diagnoses across both age groups were lateral ankle ligament sprain (n = 14, 13.6%), foot blisters (n = 11, 10.7%), and lumbar pain (n = 10, 9.7%). Ankle sprains (n = 4), anterior cruciate ligament (ACL) ruptures (n = 3) and concussion (n = 3) recorded as the highest sports incapacity injuries. The self-report data collection revealed that 46 (27.2%) athletes arrived at the tournament with an existing self-reported injury/illness and 57 (39.3%) athletes had a self-reported injury/illness at the conclusion of the ANNC (RR 1.44 95%CI 1.05–1.99, p = 0.030).

Conclusion

There are no recent studies reporting injury rates specifically in pre-elite netball players. This study found an incidence rate of 89.4 per 1000 player hours. Ankle sprains are the highest medical attention and sports-incapacity injury in pre-elite netball athletes. Foot blisters and low back pain also feature in the highest medical attention injuries and ACL rupture and concussion were high sports incapacity injuries at the ANNC’s. Finally, combining both the medical attention and self-report injury/illness data collection methods identified more injuries/illnesses than the use of one method alone.

Isometric exercise and pain in patellar tendinopathy: A randomized crossover trial

19-11-2019 – Sinéad Holden, Kristian Lyng, Thomas Graven-Nielsen, Henrik Riel, Jens Lykkegaard Olesen, Lars Henrik Larsen, Michael Skovdal Rathleff

Journal Article

Objectives

The aim of this study was to compare the acute effects of isometric versus dynamic resistance exercise on pain during a pain-provoking activity, and exercise-induced hypoalgesia in participants with patellar tendinopathy.

Design

This study was a pre-registered randomised crossover study. Participants were blinded to the study hypothesis.

Methods

Participants (N = 21) performed a single session of high load isometric resistance exercise or dynamic resistance exercise, in a randomised order separated by a 7-day washout period. Outcomes were assessed before, immediately after, and 45 min post-exercise. The primary outcome was pain intensity scored on a numeric pain rating scale (NRS; 0–10) during a pain-provoking single leg decline squat (SLDS). Secondary outcomes were pressure pain thresholds (PPTs) locally, distally and remotely, as well as tendon thickness.

Results

There was a significant decrease in pain NRS scores (mean reduction 0.9, NRS 95%CI 0.1–1.7; p = 0.028), and increase in PPTs at the tibialis anterior muscle (mean increase 34 k
Pa 95%CI 9.5–58.5; p = 0.009) immediately post-exercise. These were not sustained 45 min post-exercise for pain (NRS) or PPTs (p > 0.05). There were no differences between exercise on any outcome.

Conclusions

While patients with patellar tendinopathy decreased pain during SLDS in response to resistance training, but the magnitude was small. Contraction mode may not be the most important factor in determining the magnitude of pain relieving effects. Similarly, there were only small increases in PPTs at the tibialis anterior which were not superior for isometric exercise.

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

08-02-2020 – Gordon S. Waddington

Editorial

Low intensity rowing with blood flow restriction over 5 weeks increases V̇O2max in elite rowers: A randomized controlled trial

02-11-2019 – Steffen Held, Michael Behringer, Lars Donath

Journal Article

Objectives

The present randomized controlled intervention study examined the effects of practical blood flow restriction (p
BFR) on maximal oxygen uptake (V̇O2max) during low intensity rowing.

Design

Thirty-one elite rowers were either assigned to the intervention (INT) or control (CON) group, using the minimization method (Strata: Gender, Age, Height, V̇O2max).

Method

While INT (n = 16; 4 female, 12 male, 21.9 ± 3.2 years, 180.4 ± 8.7 cm, 73.6 ± 10.9 kg, V̇O2max: 63.0 ± 7.9 ml/min/kg) used p
BFR during boat- and indoor-rowing training, CON (n = 15, 4 female, 11 male, 21.7 ± 3.7 years, 180.7 ± 8.1 cm, 72.5 ± 12.1 kg, V̇O2max: 63.2 ± 8.5 ml/min/kg) completed the identical training without p
BFR. p
BFR of the lower limb was applied via customized elastic wraps. Training took place three times a week over 5 weeks (accumulated net p
BFR: 60 min/week; occlusion per session: 2-times 10 min/session) and was used exclusively at low intensities (<2 mmol/L). A spiroergometric ramp test (V̇O2max; 30–40 W/min increase) on rowing-ergometer and one-repetition maximum test of the squat exercise (SQ1RM) was employed to assess endurance and strength capacity.

Results

Significant group × time interactions (ηp² = 0.26) in favor of INT were found for V̇O2max (+9.1 ± 6.2%, Effect Size = 1.3) compared to CON (+2.5 ± 6.1%, ES = 0.3). SQ1RM (ηp² = 0.01) was not affected by the p
BFR intervention.

Conclusions

This study revealed that 15 sessions of p
BFR application with a cumulative total p
BFR load of 5 h over a 5 weeks macrocycle remarkably increased V̇O2max. Thus, p
BFR might serve as a promising means to improve aerobic capacity in highly trained elite rowers.

Effects of baseline fitness and BMI levels on changes in physical fitness during military service

19-02-2020 – Kai Pihlainen, Jani Vaara, Tommi Ojanen, Matti Santtila, Tommi Vasankari, Kari Tokola, Heikki Kyröläinen

Journal Article

Objectives

The purpose of the present study was to investigate how aerobic fitness, muscle fitness and body mass index (BMI) change in relation to their baseline levels during 6–12 months of military service.

Design

Retrospective longitudinal follow-up study.

Methods

The study group consisted of 249 279 healthy young male conscripts (age 19.1 ± 0.4 yrs.) who completed their military service between the years 2005–2015. Anthropometrics (body mass, height, BMI), aerobic fitness (12-min running test) and muscle fitness (sit-ups, push-ups, standing long jump) were measured.

Results

A 12-min running test improved by 5% (107 ± 292 m), standing long jump 1% (2.1 ± 16.2 cm), 1-min sit-ups 19% (4 ± 8 repetitions/min) and 1-min push-ups 33% (5 ± 10 repetitions/min) (p < 0.001 for all). Baseline fitness and baseline BMI levels were inversely associated with their changes (r = −0.37 to −0.47, p < 0.001). Performance improved in conscripts in the lowest two baseline fitness quartiles in all tests, while it decreased in conscripts in the highest fitness quartiles. In addition, in conscripts who were obese at baseline, body mass decreased on average by 4.9 ± 7.0 kg (p < 0.001).

Conclusions

On average, the physical fitness of conscripts improved during their compulsory military service. In particular, conscripts with a lower baseline fitness level or higher BMI showed the largest improvements, which may be significant findings from both a military readiness and national health perspective. However, the decline in physical performance of high-fit conscripts highlights the importance of individualization of physical training and military training load during military service.

Altered expression of proteoglycan, collagen and growth factor genes in a TGF-β1 stimulated genetic risk model for musculoskeletal soft tissue injuries

18-02-2020 – Kyle Willard, Mary-Jessica Nancy Laguette, Leonardo Alves de Souza Rios, Caroline D’Alton, Melissa Nel, Sharon Prince, Malcolm Collins, Alison Victoria September

Journal Article

Objectives

To investigate the functional effect of implicated variants within BGN and COL5A1 on gene expression of components of the extracellular matrix (ECM) in a TGF-β-stimulated risk model for musculoskeletal soft tissue injuries.

Design

Experimental research, laboratory study.

Methods

Skin biopsies were obtained from nine healthy participants with either a combined increased or reduced risk profile for COL5A1 rs12722 C > T and BGN rs1126499 C > T – rs1042103 G > A, and primary fibroblast cell lines were established. Total RNA was extracted at baseline (10% FBS), after serum starvation (1% FBS) and TGF-β1 treatment (1% FBS, 10 ng/m
L TGF-1β). Relative m
RNA levels of BGN, COL5A1, DCN and VEGFA was quantified using Taqman® array pre-spotted plate assays (Applied Biosystems, Foster city, CA, USA).

Results

At baseline, the reduced risk group had 2.5, 1.9 and 2 fold increases (p < 0.001) in relative BGN, COL5A1 and VEGFA m
RNA levels respectively. In the serum starved experiments, except for a significant 1.5 fold (p = 0.017) increase in relative DCN m
RNA expression in the reduced risk group, similar observations were noted for the other three genes. After TGF-1β treatment, the reduced risk group had 1.3 (p = 0.011) and 1.4 fold (p = 0.001) increases in the relative COL5A1 and VEGFA m
RNA levels, respectively.

Conclusions

Altered m
RNA levels associated with genetic risk profiles for musculoskeletal soft injury risk at baseline (BGN, COL5A1 and VEGFA), with serum starvation (DCN) and after TGF-β1 treatment (COL5A1 and VEGFA) provide additional functional evidence to support the association of implicated genetic loci with several musculoskeletal soft tissue injuries. Implication of altered gene expression profiles underpinning these genetic risk associated loci potentially highlight key therapeutic targets for management of these injuries.

The influence of baseball pitching distance on pitching biomechanics, pitch velocity, and ball movement

18-02-2020 – Alek Z. Diffendaffer, Jonathan S. Slowik, Karen Hart, James R. Andrews, Jeffrey R. Dugas, E. Lyle Cain, Glenn S. Fleisig

Journal Article

Objectives

To determine whether increasing pitching distance for adult baseball pitchers would affect their upper extremity kinetics, full-body kinematics, and pitched ball kinematics (ball velocity, duration of ball flight, vertical and horizontal break, strike percentage).

Design

Controlled laboratory study.

Methods

Twenty-six collegiate baseball pitchers threw sets of five full-effort fastballs from three different pitching distances (18.44 m, 19.05 m, 19.41 m) in a randomized order. Ball velocity, horizontal and vertical break, duration of ball flight, and strike percentage were computed by a ball tracking system, while pitching kinetics and kinematics were calculated with a 12-camera optical motion capture system. Repeated measures analysis of variance was utilized to detect significant differences among the three different pitching distances (p < 0.05).

Results

No significant differences in pitching kinetics and kinematics were observed among the varying pitching distances. Ball velocity and strike percentage were also not significantly different among the pitching distances, however, the duration of ball flight and horizontal and vertical break significantly increased with pitching distance.

Conclusions

Increasing pitching distance may not alter upper extremity kinetics, full-body kinematics, ball velocity or strike percentage in adult pitchers. However, as pitching distance increases the duration of ball flight and amount of horizontal and vertical break also increase. Increased ball flight duration could be an advantage for the hitter while increased ball break could help the pitcher. In conclusion, it is unlikely that moving the mound backwards would significantly affect pitching biomechanics and injury risk; however, the effects on pitching and hitting performance are unknown.

Improving the interpretation of skill indicators in professional Australian Football

15-02-2020 – William B. Sheehan, Rhys Tribolet, Mark L. Watsford, Andrew R. Novak, Michael Rennie, Job Fransen

Journal Article

Objectives

This study aimed to provide a simplified, novel method for analysing technical skill involvements in an Australian Football context by reducing the dimensionality of commonly reported skill counts obtained from Australian Football League (AFL) games. This may facilitate their practical use and interpretability.

Design

Retrospective longitudinal design where individual players’ technical skill counts were collected over three seasons of official AFL games.

Methods

Seventy-three skill count values provided publicly by Champion
Data® were collected for each match over a three-year analysis period. A principal component analysis was used to reduce the dimensionality of a large number of correlated technical skill indicators into a smaller set of uncorrelated components whilst maintaining most of the variance from the original data set.

Results

The principal component analysis derived four principal components pertaining to high-pressure success, low-pressure success, attacking ball movement ability and scoring ability.

Conclusions

This study is the first to provide a simplified, novel method for analysing technical skill counts in Australian Football. The derived metrics reveal useful information for coaches and practitioners. This may consequently ease the interpretation of skill count data available to coaches from games, guide opposition analysis, help in the design of representative practice and inform player performance ratings.

Parental awareness and engagement in the Active Kids program across socioeconomic groups

18-02-2020 – Katherine B. Owen, Bridget C. Foley, Adrian Bauman, B. Bellew, Lindsey J. Reece

Journal Article

Objectives

In 2018, the New South Wales (NSW) Government implemented a State-wide program to reduce the cost barrier to organised sport and physical activity participation. We explored parent/carer’s awareness and children’s engagement in the Active Kids program across socioeconomic groups and used the NSW Population Health Survey (PHS) to validate engagement in the program.

Design

Cross-sectional.

Methods

Data were obtained from the 2018 NSW PHS and the Active Kids program registration database. We compared demographic characteristics of children who had registered for the program in the registration database with children in the weighted NSW PHS. Multinomial regression models were used to determine whether socioeconomic status was associated with parent/carer awareness and children’s engagement in the program.

Results

Parent/carer’s in the most disadvantaged quartile were twice as likely to have never heard of the Active Kids program (OR: 2.04, 95% CIs 1.31, 3.16) or to have heard or the program but not registered (OR: 1.94, 95% CIs 1.26, 3.00), and more than twice as likely to have registered for a voucher, but not followed through and redeemed the voucher (OR: 2.68, 95% CIs 1.27, 5.63) compared with the least disadvantaged quartile.

Conclusions

The Active Kids program has provided financial support for organised sport and physical activity to a large number of children. However, there are still a substantial proportion of socially disadvantaged groups who are unaware or have not engaged in the program. Further targeted work is required to increase the awareness and engagement in the program for socially disadvantaged groups.

Evaluation of adolescent sport specialization and injury mechanism by sex: A secondary analysis

19-02-2020 – Kevin M. Biese, Eric G. Post, Daniel A. Schaefer, Mayrena I. Hernandez, M. Alison Brooks, Tim A. McGuine, David R. Bell

Journal Article

Objectives

The purpose of this study was to compare the association of sport specialization with previous overuse and acute injuries between male and female adolescent athletes.

Design

Cross-sectional study.

Methods

Questionnaires were completed by adolescent athletes from various sports at sport club summer events in the state of Wisconsin. Adolescent athletes (12–18 years old) who were active in organized sports in the previous year were recruited. The questionnaire contained demographics, sport participation, sport specialization classification, and previous injury history. Sport specialization classification was determined using common methods in sport specialization research. Previous injury was restricted to athletic injuries that occurred in the past year.

Results

Two-thousand and eleven participants (age = 13.7 ± 1.6 years, females = 989) completed the questionnaire. Highly specialized athletes were more likely to report both acute and overuse injuries compared to low specialization athletes. However, this relationship differed by sex, with only moderate and highly specialized females being more likely (Moderate: OR 95%CI = 1.74 1.18–2.58, p = 0.005; High: OR 95%CI = 1.69 1.14–2.53, p = 0.010) to report an overuse injury compared to low specialization females. Highly specialized female athletes were more likely to report an acute injury (High: OR 95%CI = 1.46 1.06–2.02, p = 0.022) compared to low specialization females. Highly specialized male athletes were not associated with overuse or acute injuries.

Conclusions

Highly specialized athletes were more likely to report acute and overuse injuries. However, when this analysis was separated by sex, only highly specialized females were more likely to report a previous overuse or acute injury.

The effect of training order on neuromuscular, endocrine and mood response to small-sided games and resistance training sessions over a 24-h period

18-02-2020 – W. Sparkes, A.N. Turner, M. Weston, M. Russell, M.J. Johnston, L.P. Kilduff

Journal Article

Objectives

This study examined the acute effect of small-sided-game (SSG) and resistance training sequence on neuromuscular, endocrine and mood response over a 24-h (h) period.

Design

Repeated measures.

Methods

Fourteen semi-professional soccer players performed SSG-training (4vs4 + goalkeepers; 6 × 7-min, 2-min inter-set recovery) followed by resistance training 2 h later (back-squat, Romanian deadlift, barbell-hip-thrust; 4 × 4 repetitions, 4-min inter-set recovery; 85% 1 rep-max) (SSG + RES), and on a separate week reversed the session order (RES + SSG). Physical demands of SSG’s were monitored using global positioning systems (GPS) and ratings of perceived exertion (RPE). Countermovement-jump (CMJ; peak power output; jump height) and brief assessment of mood were collected before (pre), during (0 h) and after (+24 h) both protocols. Salivary testosterone and cortisol concentrations were obtained at the same time-points but with the inclusion of a measure immediately prior to the second training session (+2 h).

Results

GPS outputs and RPE were similar between SSG-training during both protocols. Between-protocol comparisons revealed no significant differences at +24 h in CMJ performance, mood, and endocrine markers. Testosterone was higher at 0 h during RES + SSG in comparison to SSG + RES (moderate-effect; +21.4 ± 26.7 pg ml−1; p = 0.010), yet was similar between protocols by +2 h.

Conclusions

The order of SSG and resistance training does not appear to influence the physical demands of SSG’s with sufficient recovery between two sessions performed on the same day. Session order did not influence neuromuscular, endocrine or mood responses at +24 h, however a favourable testosterone response from the resistance first session may enhance neuromuscular performance in the second session of the day.

Large increases in plasma fast skeletal muscle troponin I after whole-body eccentric exercises

19-02-2020 – Trevor C. Chen, Hung-Wen Liu, Alan Russell, Benjamin L. Barthel, Kuo-Wei Tseng, Min-Jyue Huang, Tai-Yi Chou, Kazunori Nosaka

Journal Article

Objectives

It has been reported that plasma fast skeletal muscle troponin I (fs
Tn
I) but not slow skeletal muscle troponin I (ss
Tn
I) increases after a bout of eccentric exercise of the elbow flexors. The present study compared the first and second bouts of whole-body eccentric exercises for changes in plasma fs
Tn
I and ss
Tn
I concentrations.

Design

Observational study in an experimental group.

Methods

Fifteen sedentary men (20–25 y) performed nine eccentric exercises targeting arm, leg and trunk muscles, and repeated them two weeks later. Blood samples were taken before and for five days following each bout, and plasma ss
Tn
I and fs
Tnl concentrations were measured by enzyme-linked immunosorbent assays. Their changes were compared between bouts and their relationships to plasma CK activity and myoglobin concentrations were analysed.

Results

Plasma fs
Tn
I concentration increased after the first bout and peaked at 4 days post-exercise (2152–40,295 ng/m
L), but no significant increases were evident after the second bout. Plasma ss
Tn
I concentration did not change significantly from the baseline (<0.08 ng/m
L) after either bout. Peak plasma fs
Tn
I concentration was significantly (p < 0.005) correlated with peak plasma CK activity (peak: 23,238–207,304 IU/L, r = 0.727) and myoglobin concentration (1047–3936 μg/L, r = 0.625) after the first bout.

Conclusions

These results suggest that plasma Tn
I concentrations are more specific biomarker of muscle damage than plasma CK activity and myoglobin concentration. It seems that the whole-body eccentric exercises induced damage preferentially to fast-twitch muscle fibres, and increases in plasma CK activity and myoglobin concentration after eccentric exercise may reflect fast-twitch muscle fibre damage.

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

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

Journal Article

Objectives

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

Design

Controlled laboratory study.

Methods

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

Results

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

Conclusion

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

Y balance test: Are we doing it right?

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

Journal Article

Objectives

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

Design

Descriptive laboratory study.

Methods

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

Results

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

Conclusions

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

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.

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

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

Journal Article, Review

Objectives

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

Design

Systematic review, meta-analysis and meta-regression.

Methods

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

Results

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

Conclusions

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

From accelerometer output to physical activity intensities in breast cancer patients

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

Journal Article

Objectives

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

Design

Laboratory study.

Methods

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

Results

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

Conclusions

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

Quantifying cycling as a foundational movement skill in early childhood

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

Journal Article

Objectives

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

Design and Methods

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

Results

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

Conclusion

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

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

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

Journal Article

Objectives

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

Design

Randomised, controlled trial.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

Cross-sectional.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

Observational validation-study.

Methods

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

Results

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

Conclusions

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

Bone geometry and lower extremity bone stress injuries in male runners

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

Journal Article

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

Objectives

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

Design

Cross-sectional.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objective

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

Design

Cross-sectional survey study.

Methods

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

Results

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

Conclusion

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

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

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

Journal Article

Objectives

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

Design

Observational cohort study.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article, Review

Objectives

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

Design

Systematic review. Prospero registration number: CRD42017064290.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article, Review

Study design

Systematic review of randomized controlled trials.

Objectives

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

Methods

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

Results

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

Conclusion

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

Level of evidence

Level 1.

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

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

Journal Article

Objectives

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

Design

Longitudinal cohort.

Methods

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

Results

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

Conclusions

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

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

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

Journal Article

Objectives

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

Design

Prospective multi-center, cross-sectional study.

Methods

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

Results

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

Conclusion

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

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

12-01-2020 – Gordon S. Waddington

Editorial, Introductory Journal Article

Running for your life: A qualitative study of champion long-distance runners’ strategies to sustain excellence in performance and health

18-02-2020 – Victor Bargoria, Toomas Timpka, Jenny Jacobsson, Karin Halje, Christer Andersson, Gerhard Andersson, Stéphane Bermon

Journal Article

Objectives

To investigate champion long-distance runners’ strategies for managing injury and illness symptoms and staying well.

Design

Qualitative research study.

Methods

Twelve long-distance runners were interviewed immediately after having competed in World Championships finals. Thematic analysis was used to categorise and structure the data. The results were presented as primary themes and overarching constructs representing connections between the primary themes.

Results

The champion runners’ basic tactic to manage symptoms of ill health was characterized by rapid adjustment of sports load and a strong incentive to learn from experience and professional advice. This tactic was named here educated flexibility. A secondary exigency tactic was associated with reaching short-term goals and a consequential acceptance of health hazards. The runners used economic and other environmental strain to explain use of the exigency tactic. Most champion runners’ long-term strategy to stay well included both tactics successfully combined to maintain a performance level assuring a regular income. Avoidance of letting environmental strain and health problems create vicious circles was at the centre of these strategies.

Conclusions

Champion runners’ main strategy to stay well and sustain their superiority in performance was characterized by constantly paying attention to symptoms of ill health, listening to medical advice, and not letting environmental strain interfere with adjustment of sports load. Many top-level runners originate from global regions where formal education programs and health insurance plans are poorly regulated and supported. Bio-psychosocial models including empowerment at individual and systems levels should be considered when health services are planned for professional runners.

Injury epidemiology in Australian male professional soccer

06-02-2020 – Donna Lu, Alan McCall, Mark Jones, Stephanie Kovalchik, Jeff Steinweg, Les Gelis, Rob Duffield

Journal Article

Objectives

To describe the injury epidemiology of the Australian male professional soccer league (A-League) over 6 consecutive seasons.

Design

Prospective observational cohort study.

Methods

Match-loss injury data was collected from each A-League club (n = 10) for each competition match (n = 27/season) over 6 seasons (2012/13–2017/18). Injuries were collected weekly through a standardised protocol and were classified by setting, mechanism, severity, the type and location on the body. Generalised Linear Models were used to estimate the injury incidences (injury/round/season), whilst rate ratios were reported for total injuries and within abovementioned injury classifications.

Results

Overall injury incidence was not significantly different ranging from 4.8 (95%CI:4.1–5.8) to 6.7 (95%CI:5.8–7.8) between seasons 2012/13 to 2017/18 (p > 0.05). Match injuries remained stable whilst training injuries decreased across the 6 seasons (exp(β) 0.5995%CI:0.36–1.0; p = 0.04). Respectively, contact and non-contact injuries were not significantly different across the 6 seasons, although non-contact injuries were more common than contact injuries (p > 0.05). Mild severity injuries decreased (exp(β) 0.64 95%CI:0.4–0.9;p = 0.02), whilst moderate severity injuries increased (exp(β) 1.7 95%CI:1.0–2.8;p = 0.04) in season 2017/18 compared to 2012/13. The most common injuries were at thigh (23–36%), of which the majority were hamstring injuries (54%–65%) of muscle/tendon type (50–60% of total injuries/season). Injuries remained stable across the seasons by type and location (p > 0.05 and p > 0.05, respectively).

Conclusions

Injury rates, mechanisms, locations and types have remained relatively stable over recent seasons of the A-League. Current Australian professional soccer league medical practices may have contributed to the stability of injury rates.

Profile and cost of sport and exercise-related hand and wrist injuries with Emergency Department presentation

03-02-2020 – Luke Steven Robinson, Ted Brown, Lisa O’Brien

Journal Article

Objectives

Injuries to the hand and wrist from sport and exercise are common and costly. This cost-of-illness analysis was performed to estimate the economic implications of hand and wrist injuries that were sustained as a result of participation during sport or exercise.

Perspective

Cost estimates were calculated from resource use in the emergency, inpatient and outpatient settings from the perspective of one public healthcare service.

Setting

Alfred Health, a large public health service with two emergency departments located in Victoria, Australia.

Methods

This descriptive epidemiological study used ICD-10 diagnostic codes and electronic billing records to identify 778 potential cases for inclusion. Electronic medical records were screened and reviewed to extract demographic and patient care journey data.

Results

692 individuals, (n = 761 individual zone of injuries), were included. Australian Rules Football (ARF) was the largest contributor to injuries (20.2%) followed by riding bicycles (15.9%. The total cost of all injuries was $790,325, with a median cost per case of $278 IQR $210–$282 in the Emergency Department n = 692, $3328 IQR $2242–$6441 in the inpatient setting n = 76 and $630 IQR $460–$870 in the outpatient setting n = 244.

Conclusions

Hand and wrist injuries sustained from sport and exercise contribute to a significant financial burden on the healthcare system. Future research that considers the costs that occur outside of the public healthcare service is required estimate the burden associated with these injuries comprehensively. Injury prevention programs may mitigate the observed injury trends.

Medication information and supply behaviours in elite and developing athletes

12-02-2020 – Danae Perry, Bronte Librizzi, Lily Ngu, Michael Ricciardello, Amy Street, Rhonda Clifford, Carmel Goodman, Peter Peeling, Sandra M. Salter

Journal Article

Objectives

To investigate the behaviours of elite and developing athletes in obtaining medications and medication information, and to identify the role of pharmacists in athlete care.

Design

Cross-sectional survey.

Methods

An electronic, 39-item questionnaire was developed, piloted and distributed to elite and developing athletes aged 18 years and above at a state-based sporting institute. Quantitative data was analysed using descriptive statistics and free text comments were analysed using an inductive reasoning approach.

Results

A total of 98 responses were analysed. Ninety (n = 90/98, 91.84%) participants obtained medications in the six months prior to survey completion. Pharmacies were the most common source of both prescription (n = 67/69, 97.10%) and non-prescription medications (n = 64/75, 85.33%). Forty-five (n = 45/98, 45.92%) participants also attended pharmacies when they had a minor ailment. Sixty-two (n = 62/98, 63.27%) participants ‘sometimes’ consulted pharmacists for medication information. Only 11 (n = 11/98, 11.22%) knew, according to their sporting institute medication policy, that athletes were required to consult a medical practitioner before taking anti-inflammatory, pain-relieving or sleep-inducing medications. Forty (n = 40/98, 40.82%) participants believed pharmacists could play a role in their medication management.

Conclusions

Many elite and developing athletes visited pharmacies for medication supply and treatment of minor ailments. Doping regulatory agency websites were the most commonly used and trusted sources for medication information, although some athletes believed pharmacists could also contribute to their medication management. Future research should consider whether pharmacists are ready for a role in sports pharmacy.

Evaluation of the bilateral function in para-athletes with spastic hemiplegia: A model-based clustering approach

21-01-2020 – Raúl Reina, David Barbado, César Soto-Valero, José M. Sarabia, Alba Roldán

Journal Article

Objectives

Spastic hemiplegia is one of the most common forms of cerebral palsy, in which one side of the body is affected to a greater extent than the other one. Hemiplegia severity (i.e. moderate vs mild forms) is currently used in some Para sports for classification purposes. This study evaluates the sensitivity of several tests of stability (e.g. one-legged stance test), dynamic balance (side-step test), coordination (rapid heel-toe placements), range of movement (backward stepping lunge), and lower limb power (the triple hop distance and the isometric peak force of the knee extensors) to discriminate between the impaired and unimpaired lower extremities’ function in para-athletes with spastic hemiplegia.

Methods

A sample of 87 international para-athletes with cerebral palsy took part in the study, and their bilateral performance was measured for the abovementioned tests. The tests’ sensitivity to discriminate between impaired vs unimpaired legs was assessed using Boruta’s method.

Results

The triple hop distance, the magnitude of the mean velocity in the one-legged stance test and the time to perform the rapid heel-toe placement test are the most sensitive variables when performing random forest classifiers. In addition, the study confirms two optimal clusters by Gaussian finite mixture models to represent the athletes’ performance.

Conclusions

Reference scores for the clusters are provided, demonstrating that coordination, balance, and power of the lower limbs are relevant variables for classifying para-athletes with spastic hemiplegia.

Bowling loads and injury risk in male first class county cricket: Is ‘differential load’ an alternative to the acute-to-chronic workload ratio?

27-01-2020 – Alexander Tysoe, Isabel S. Moore, Craig Ranson, Steve McCaig, Sean Williams

Journal Article

Objectives

Methodological concerns relating to acute-to-chronic workload ratios (ACWR) have been raised. This study aimed to assess the relationship between an alternative predictor variable named ‘differential load’, representing the smoothed week-to-week rate change in load, and injury risk in first class county cricket (FCCC) fast bowlers.

Design

Prospective cohort study.

Methods

Bowling loads and injuries were recorded for 49 professional male fast bowlers from six FCCC teams. A range of differential loads and ACWRs were calculated and subjected to a variable selection procedure.

Results

Exponentially-weighted 7-day differential load, 9:21-day ACWR, 42-day chronic load, and 9-day acute load were the best-fitting predictor variables in their respective categories. From these, a generalized linear mixed-effects model combining 7-day differential load, 42-day chronic load, and 9-day acute load provided the best model fit. A two-standard deviation (2SD) increase in 7-day differential load (22 overs) was associated with a substantial increase in injury risk (risk ratio RR = 2.47, 90% CI: 1.27–4.80, most likely harmful), and a 2SD increase in 42-day chronic load (17.5 overs/week) was associated with a most likely harmful increase in injury risk (RR = 6.77, 90% CI: 2.15–21.33). For 9-day acute load, very low values (≤1 over/week) were associated with a most likely higher risk of injury versus moderate (17.5 overs/week; RR: 15.50, 90% CI: 6.19–38.79) and very high 9-day acute loads (45.5 overs/week; RR: 133.33, 90% CI: 25.26–703.81).

Conclusions

Differential loads may be used to identify potentially harmful spikes in load, whilst mitigating methodological issues associated with ACWRs.

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

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

Journal Article

Objectives

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

Design

Descriptive, observational.

Methods

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

Results

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

Conclusions

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

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

18-01-2020 – Lindsay E. Nylund, Peter J. Sinclair, Peta L. Hitchens, Stephen Cobley

Letter

Audit of a cardiac screening policy for elite Australian cricketers

21-01-2020 – Jessica J. Orchard, John W. Orchard, Andre La Gerche, Alex Kountouris, Hariharan Raju, Mark Young, Rajesh Puranik, Chris Semsarian

Journal Article

Objectives

To report the compliance and results of an electrocardiogram (ECG) cardiac screening program in male and female elite Australian cricketers.

Design

cross-sectional study.

Methods

Elite cricketers were offered screening in accordance with Cricket Australia policy. Players who consented provided a personal and family history, physical examination and resting 12-lead ECG. An audit (1 February 2019) examined all cardiac screening records for male and female players in all Australian Cricket state squads from 16 years upwards. Data extracted from the Cricket Australia database included the number of players who underwent screening; signed waivers opting out; and had follow-up tests. ECGs were re-reviewed according to the International Criteria.

Results

710 players were included in the cohort (mean age 20.4 ± 4.9 years, 62% male). 692 (97.5%) players underwent recommended cardiac screening or signed a waiver opting out (1.1%). 173 (24.4%) players were screened (or signed a waiver) more than once. Follow-up testing was conducted for 59 (6.9%) cases. No players were excluded from sport due to a cardiac problem and no major cardiac incidents occurred to any player in the audit cohort. Review of 830 ECGs showed benign athlete heart changes, including sinus bradycardia (33.5%), left ventricular hypertrophy (16.3%), and incomplete/partial right bundle branch block (8.4%), were common but abnormal screening ECGs were uncommon (2.0%).

Conclusions

An audit of a cardiac screening program in elite Australian cricketers found excellent compliance. A small proportion required follow-up testing and no player was excluded from sport due to a cardiac problem. ECG analysis suggested cricket is a sport of moderate cardiac demands, with benign athlete heart changes common.

Serum ferritin distribution in elite athletes

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

Journal Article

Objectives

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

Design

Retrospective cohort study.

Methods

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

Results

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

Conclusions

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