Children and exercise.

BACKGROUND: Exercise is widely understood to improve health outcomes in children and adolescents and to contribute to the prevention and management of many chronic conditions. Australian children are not currently meeting the recommended physical activity guidelines, and these habits are likely to extend into adulthood without intervention. OBJECTIVE: The aim of this paper is to provide general practitioners (GPs) with the tools to perform a basic exercise assessment with children and adolescents and an understanding of the core principles of exercise prescription for general and special paediatric populations. DISCUSSION: GPs are limited by time often precluding the assessment of exercise levels in children and adolescents unless it is immediately relevant to their presentation. This article discusses simple methods of assessing physical activity, the importance of appropriately prescribed exercise and its benefits for physical, psychological and social health and wellbeing.

Association of Sleep Disturbance With Neurocognition, Symptom Severity, and Recovery in Pediatric Concussion: A 10-Year Retrospective Analysis of a Tertiary Referral Concussion Clinic.

OBJECTIVES: To investigate the relationship between sleep disturbance, neurocognition, symptom severity, and recovery in children and adolescents with concussion. Sex-related comparisons were also examined. SETTING: Pediatric tertiary referral concussion clinic. PARTICIPANTS: Children and adolescents (aged 6-18 years; n = 554) diagnosed with concussion. DESIGN: Cross-sectional retrospective study. MAIN MEASURES: Assessment data were obtained from Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) Applications. Sleep disturbance was quantified using the sleep-related domains of the Post-Concussion Symptom Scale (PCSS) and self-report sleep duration. Sleep duration was categorized as short (<7 hours), intermediate (7-9 hours), and long (≥9 hours). Outcome measures included neurocognition, measured via composite scores of ImPACT cognitive domains (verbal memory, visual memory, visual motor speed, reaction time); symptom severity, using the PCSS; and concussion recovery time (days). RESULTS: Short sleep resulted in significantly poorer verbal memory ( P = .03), visual memory ( P = .02), and reaction time ( P = .01). Sleep disturbance was strongly associated with total symptom burden (ρ = 0.90, P < .001). Recovery time, median (interquartile range), was significantly prolonged with short sleep, 61 (30-136) days, compared with intermediate, 38 (21-72) days, and long, 34 (19-71) days, sleep ( P < .001). Overall, female participants demonstrated significantly longer recovery times than male participants (mean 91 ± 95 vs 58 ± 85 days, P < .001). Females exhibited similar concussion recovery times irrespective of reported sleep duration ( P = .95), whereas mean recovery time in males was significantly longer with short sleep (84 ± 82 days) than with intermediate (61 ± 106 days) and long (49 ± 62 days) sleep ( P < .001). CONCLUSION: Sleep disturbance following concussion poses as a promising modifiable risk factor to alleviate postinjury impairments, including cognitive deficits and symptom burden. Female children were found to experience more severe concussion symptoms and protracted recovery times than their male counterparts. Investigations into the factors that may contribute to sex-related differences following concussion are warranted.

The Utility of Melatonin for the Treatment of Sleep Disturbance After Traumatic Brain Injury: A Scoping Review.

OBJECTIVE: To investigate the utility of melatonin supplementation as a treatment option for individuals with sleep disturbance after traumatic brain injury (TBI). DATA SOURCES: A systematic search was conducted in 6 electronic databases (Medline, AMED, CINAHL, Embase, Scopus, and SPORTDiscus) from earliest records to April 2022. STUDY SELECTION: Studies were eligible for inclusion if they met the following criteria: a) human participants with sleep disturbance after TBI, b) melatonin or melatonergic agent used as an intervention to treat sleep disturbance, and c) outcomes of melatonin administration reported. All TBI severity types (mild, moderate, and severe) were eligible. The initial search retrieved a total of 595 articles, with 9 studies meeting the eligibility criteria. DATA EXTRACTION: Two reviewers independently extracted data from eligible studies and assessed methodological quality. Extracted data consisted of participant and injury characteristics, melatonin interventional properties, and sleep outcome. Methodological quality was assessed via the Downs and Black checklist. DATA SYNTHESIS: A total of 251 participants with TBI-induced sleep disturbance (mean age range: 14.0-42.5 years) were included. Melatonin, Circadin (prolonged-release melatonin), or Ramelteon (melatonin receptor agonist) were administered. Dosages and intervention duration ranged from 2 to 10 mg and 3 to 12 weeks, respectively. Eight out of 9 studies reported positive outcomes after melatonin treatment. Significant improvements in subjective sleep quality, objective sleep efficiency, and total sleep time were found with melatonin. Reductions in self-reported fatigue, anxiety, and depressive symptoms were also observed with melatonin treatment. No serious adverse events were reported after melatonin administration. CONCLUSION: Melatonin has good tolerability after short-term use and the potential to be a therapeutic agent for those with sleep disturbance after TBI. Melatonin was shown to be beneficial to sleep quality, sleep duration, and sleep efficiency. Additional clinically relevant outcomes of improved mental health suggest that melatonin use may be a promising treatment option for individuals experiencing co-occurring disorders of mood and sleep disturbance post-injury.

Effects of Age and Sex on Aerobic Fitness, Sprint Performance, and Change of Direction Speed in High School Athletes.

ABSTRACT: Hackett, DA, He, W, Fleeton, JRM, Orr, R, and Sanders, RH. Effects of age and sex on aerobic fitness, sprint performance, and change of direction speed in high school athletes. J Strength Cond Res 37(5): 325-331, 2023-The purpose of this study was to examine the effects of sex and age on aerobic fitness, sprinting performance, and change of direction speed (CODS) in high school athletes, with consideration for maturity. This cross-sectional study involved 2,132 adolescents (1,415 male and 717 female athletes) aged 12.0-15.9 years. Assessment of aerobic fitness using the 20-m multistage fitness test (20MSFT) and 20-m sprint and CODS using the 505 test was performed. For the analysis of data, subjects were separated into 4 age groups: U/13 years, U/14 years, U/15 years, and U/16 years. Estimated age at peak height velocity was a covariate in the data analysis to control for maturity status. Compared with female athletes, male athletes had superior performances at all age groups in 10-m sprint ( p < 0.001, effect size [ES] = >-0.44), 20-m sprint ( p < 0.001, ES = >-0.55), and 505 test ( p < 0.001, ES = >-0.41). Female athletes performed better than male athletes in 20MSFT at U/13 ( p < 0.01, ES = -0.22); however, male athletes had better performances at U/15 ( p < 0.01, ES = 0.27) and U/16 ( p < 0.001, ES = 0.67). At each consecutive age group, male athletes improve their performances in 20MSFT and sprints and at U/14 and U/16 in the 505 test ( p < 0.001, ES > -0.37). Female athletes showed no improvement in the 20MSFT and 505 test between U/13-U/16 but showed improved sprint performance at U/15 compared with U/13 and at U/16 compared with U/14 ( p < 0.05). This study shows that adolescent male athletes perform consistently better than female athletes in running-related field-based tests and display continuous improvements across age groups.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

ABSTRACT: Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res 36(8): 2176-2185, 2022-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Effect of high-volume cluster sets versus lower-volume traditional sets on muscular performance.

BACKGROUND: Similar muscle performance adaptations have been shown following volume-equated resistance training using cluster (CLUS) versus traditional (TRAD) set structures. This study aimed to examine the effects of higher-volume CLUS compared to lower-volume TRAD set structures on muscle performance. METHODS: Twenty resistance-trained males (age 20.9±4.3 years) were randomized into one of two bench press training routines performed for 6 weeks. Subjects in CLUS (N.=10), performed six sets of five repetitions at 85% one-repetition maximum (1RM) with 30 seconds inter-repetition rest and three minutes of inter-set rest. In contrast, subjects in TRAD (N.=10) performed three sets of five repetitions at 85% 1RM with five minutes of inter-set rest. Muscular strength (1RM), concentric velocity, power, local muscular endurance and maintenance of muscle performance (in training sessions) were assessed. RESULTS: For 1RM there was a significant time effect (P<0.001) with moderate effect sizes (ES) within each group (CLUS: ES=0.48; TRAD: ES=0.67). A trend towards significant time effect was found for concentric velocity (P=0.05; CLUS: ES=-0.36; TRAD ES=-0.96). There were no other significant time or group effects nor group × time interactions. Greater maintenance of concentric velocity and power (sets 1-3) was found for CLUS compared to TRAD at week one (P<0.05) but not at week 6. CONCLUSIONS: High load resistance training in the bench press exercise, utilizing intra-set rest periods to increase the training volume, does not yield any muscular performance benefits compared to traditional set structures.

Greater symptom burden results in reduced exercise tolerance in adolescents following concussion.

OBJECTIVES: To explore the relationship between symptoms and exercise tolerance in adolescents following concussion. METHODS: A retrospective analysis of 417 adolescents who attended a concussion service between January 2015 and April 2021 was performed, with 149 meeting eligibility criteria for inclusion. Post-Concussion Symptom Scale (PCSS) and graded exercise tolerance time (min) were assessed at initial and follow-up visits. Spearman's correlation was used to examine the relationship between PCSS scores and exercise time. RESULTS: Adolescents (n = 149, 13.9 ± 1.7 years, 66.4% male) presented at 28.6 ± 19.7 days post-injury. Statistically significant correlations were identified between initial (r = -0.36, p < .001) and follow-up (r = -0.41, p < .001) PCSS scores and exercise time among all participants. Initial PCSS and initial exercise time were inversely correlated for males (r = -0.24, p = .018) and females (r = -0.22, p = .127). Follow-up PCSS and follow-up exercise time were inversely correlated for males (r = -0.30, p = .003) and females (r = -0.35, p = .014). CONCLUSION: There is a statistically significant relationship between higher PCSS and poorer exercise time and both factors should be considered together to provide the most accurate assessment, particularly in females.

Early injury evaluation following concussion is associated with improved recovery time in children and adolescents.

OBJECTIVES: Delayed treatment for paediatric concussion may impact recovery trajectory. This study aims to determine the relationship between time to evaluation and concussion recovery in children and adolescents. DESIGN: Retrospective cross-sectional study. METHODS: Records from 341 children and adolescents, aged 7-18 years, from a tertiary referral concussion clinic were analysed. All participants were assessed using a standardised concussion test battery by a specialist concussion physician and graded exercise testing. Evaluation time was defined as the number of days from injury occurrence to first presentation at the concussion clinic. Three distinct time to evaluation periods were categorised as: early evaluation (<14 days), mid evaluation (14-28 days), and late evaluation (>28 days). The main outcome measure was recovery time (days). RESULTS: A total of 341 participants (mean age 13.0 ±â€¯2.3, 74% male) were included in the study. Of these, 89 received evaluation during the early phase (mean age 12.2 ±â€¯2.5, 65% male), 124 during the mid phase (mean age 13.1 ±â€¯2.2, 81% male) and 128 during the late phase (mean age 13.5 ±â€¯2.1, 75% male) following injury. Participants receiving late evaluation took three times longer to recover (mean 148.0 days, 95% CI: 121.1-173.9) compared to early (mean 38.7 days, 95% CI: 30.7-46.7) and mid (mean 51.5 days, 95% CI: 39.7-63.4) evaluation. There was a strong positive correlation between recovery time and evaluation time (r = 0.66, p < 0.001). CONCLUSIONS: Delaying time to evaluation following a concussion can significantly prolong recovery from injury in children and adolescents.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

ABSTRACT: Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res XX(X): 000-000, 2021-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Effects of age and sex on field-based measures of muscle strength and power of the upper and lower body in adolescents.

Field-based tests including the medicine ball chest throw (MBCT) and vertical jump are used to assess muscle performance. To date no study has compared performances of these field-based tests in adolescents across a range of ages. The aim of this study was to examine the effects of age and sex on MBCT and countermovement jump (CMJ) performance in adolescents.This cross-sectional study involved 2192 adolescents (1477 males and 715 females) aged between 12 and 17 years. Trials of the MBCT and CMJ were performed with CMJ peak power estimated. Males had significantly greater MBCT distance, CMJ height and CMJ peak power at each consecutive age group separated by 1 year (p < 0.001). Females generally showed significantly greater performances across a larger age range of at least 2 years for MBCT (p ≤ 0.004) and CMJ peak power (p ≤ 0.018). Males had greater performances than females for MBCT distance, CMJ height, and CMJ peak power from 13 years and above (p < 0.001). Sex differences widened with increasing age for all tests from ~5-8% at 12 years progressing to 24-29% at 16-17 years. This study shows the effects of age and sex is similar for both the MBCT and CMJ tests in adolescents.

Graded Exercise Testing Predicts Recovery Trajectory of Concussion in Children and Adolescents.

OBJECTIVE: To determine whether graded exercise testing can predict recovery trajectory of concussion in children and adolescents. DESIGN: Prospective study. SETTING: Children's Hospital, Westmead, Australia. PARTICIPANTS: One hundred thirty-nine children aged 12 to 16 years at 5 to 7 days after an acute concussive injury. INTERVENTION: Graded exercise testing on a treadmill at the subacute phase to assess symptom provocation and determine clinical recovery indicating readiness to commence a return to activity (RTA) protocol. Exercise time to symptom exacerbation and clinical recovery were measured. MAIN OUTCOME MEASURES: Standard concussion assessment and clinical testing (neurocognitive, vestibular/ocular, and balance) were conducted to determine major clinical drivers/indicators. RESULTS: Participants (mean age 12.4 ± 2.8 years, 73% male) had a confirmed sport-related concussion. The main clinical drivers identified on exercise testing were headache, balance, and vestibular dysfunction. Participants fell into 1 of 2 groups, exercise-tolerant (54%) and exercise-intolerant (46%). Exercise-tolerant patients showed mild clinical indicators, no symptom exacerbation during 10.3 ± 3.3 minutes of exercise, were safely transitioned to a RTA protocol, and recovered within 10 days. Exercise-intolerant patients had high clinical indicators, significant symptom exacerbation at 4.2 ± 1.6 minutes of exercise, and prolonged recovery of 45.6 days. No adverse effects from exercise were reported in either group. Combined use of provocative exercise and clinical testing was 93% predictive of outcome. CONCLUSIONS: Exercise testing during the subacute phase after a concussion can predict longer recovery. Exercise testing can identify a unique window where patients can be safely transitioned to activity, enabling clinicians to better inform patients and families, allocate resources and streamline care.

Epidemiology of injuries in Australian junior rugby league players.

OBJECTIVES: Conduct a large-scale epidemiological study of injury characteristics (location, type, mechanism, severity, burden) and incidence in community junior rugby league. DESIGN: Prospective cohort epidemiology study. METHODS: Injury surveillance was conducted in three district leagues (Penrith, Canberra, Melbourne) in under 6 (U6) to under 18 years (U18) age groups across the 2016 season. Club sports trainers recorded all match/training medical-attention injuries using a commercial electronic application which recorded injury circumstances and characteristics. RESULTS: A total of 13,169 players from 897 teams participated and 408 (89% male) players sustained 485 injuries, 94% of which were match related. The overall injury incidence was 5.9 injuries/1000 player hours and highest in U13-U18 female players (22.2 injuries/1000 player hours). The mean injury severity of 16±31 days missed training/match-play caused an overall injury burden of 94.2 days missed/1000 player hours). Tackles accounted for 84% of injuries. Joint and contusion injuries were the most prevalent injury type and the head (35% total injuries, primarily bruising and bleeding) was the most injured body site. CONCLUSIONS: This is the first study to report injuries across a large cohort of all-age Australian community junior rugby league players over one season. Injury prevalence was lower than previously reported in junior rugby league suggesting the sport has not become more dangerous for junior players. These findings provide an evidence-base to inform or revise policy, training and injury prevention programs and athlete development pathways in relation to game-wide safety and develop best-practice protocols in injury management for rugby league athlete support personnel.

Movement Demands and Injury Characteristics in Under-20-Years University Rugby Union Players.

CONTEXT: Rugby union is a field-based collision sport with high injury rates. Associations between injury characteristics and global positioning system-derived movement demands in rugby union athletes are yet to be investigated. OBJECTIVE: To investigate associations between match injuries and movement demands, anthropometrics, and physical performance in under-20-years university-level rugby union players. DESIGN: Descriptive epidemiology study. SETTING: Competition season. PATIENTS OR OTHER PARTICIPANTS: Rugby union players (n = 34, age = 19.3 ± 0.6 years) from a university club were recruited. MAIN OUTCOME MEASURE(S): Acute medical attention non-time-loss (NTL), medical-attention time-loss (TL), and total medical-attention (MA) injuries sustained were recorded. Principal component (PC) analysis was performed on player-movement demand variables to identify independent-movement demand components. Pearson correlation and bivariate linear regression were used to test associations between match injuries and PCs. Anthropometric and physical performance measures were tested as predictors of match injuries using a forward stepwise multiple regression analysis. RESULTS: Backs had lower anthropometric and performance measures than forwards (P < .05), whereas forwards performed fewer weekly movement demands than backs (P < .05). Increases in body mass and skinfold thickness were associated with more injuries (P < .05). Principal component analysis revealed 3 PCs representing overall performance, high-intensity running (HIR) performance, and impacts. Increases in HIR were associated with decreases in NTL upper limb and trunk (r = -0.32, P = .03), NTL musculoskeletal (r = -0.36, P = .05), NTL total (r = -0.46, P < .01), TL musculoskeletal (r = -0.30, P = .05), MA musculoskeletal (r = -0.41, P < .01), and MA total (r = -0.48, P < .01) injuries. Increases in impacts were associated with increased TL (r = 0.32, P = .03) and MA (r = 0.33, P = .03) head or neck injuries. CONCLUSIONS: Backs experienced greater weekly movement demands than forwards. Increases in HIR demands were associated with decreased acute injuries in university rugby players. Increases in impacts were associated with more acute head or neck injuries. Positional differences in movement demands, anthropometrics, and physical performance highlight the need for position-specific training.

Effectiveness of Active Learning that Combines Physical Activity and Math in Schoolchildren: A Systematic Review.

BACKGROUND: Despite increased interest in combining learning and physical activity (PA), the academic and PA benefits of active learning are uncertain. METHODS: A systematic search of 5 databases for studies combining learning math with PA in primary/elementary schools was conducted. Academic benefit was evaluated by pre-post intervention math scores compared to a control group. Effect sizes (ES) were extracted/calculated when possible. Due to study heterogeneity, meta-analysis was not conducted. RESULTS: Six randomized controlled trials and 5 quasi-experimental studies evaluating 4082 participants (53% girls; mean age 7.5-11.1 years) were eligible. Math scores were significantly better in the intervention group in 6 of 11 studies on at least 1 test (ES: 0.42-4.7; p ≤ .03). Other math tests either were not all statistically significant (2 studies) or the benefit varied across grades (1 study). No studies reported a decline in math scores. Of studies measuring PA with accelerometers, 4 of 5 reported significantly greater PA in the intervention group during the intervention (p < .05) or across the school day (p < .01). CONCLUSIONS: Undertaking PA while learning was largely equivocal for math scores but showed promising results for increasing daily PA, without detrimental effects on math performance. The need for more rigorous studies with comprehensive assessment of academic performance and PA is highlighted.

Association of Simple Step Test With Readiness for Exercise in Youth After Concussion.

OBJECTIVES: We hypothesized that a submaximal step test would be associated with readiness to commence graded exercise in children and adolescents with concussion. METHODS: Children and adolescents aged 8 to 18 years performed standard concussion clinical assessment for vestibular/ocular and balance impairment, and exercise examination utilizing the 3-minute Kasch Pulse Recovery test (KPR) and a symptom-limited graded exercise test (GXT). Outcome measures included activity readiness and symptom exacerbation. RESULTS: Forty-five participants (mean age 13.2 ± 2.1 years, 76% male) had a confirmed concussion (73% sports-related). Some participants required follow-up testing giving 75 clinical presentations. Sensitivity and specificity of the KPR were 100% and 95.7%, respectively. Area under the receiver operating characteristics curve was 0.979. Activity readiness to GXT and KPR was strongly associated (χ = 21.672, P < .001), while symptom exacerbation showed a significant correlation between testing methods (r = 0.796, P < .001). Better exercise performance on GXT and KPR was significantly correlated with normal Vestibular/Ocular Motor Screening (rs = -0.380, P = .010, and rs = -0.281, P = .017, respectively) and Modified Balance Error Scoring System (rs = -0.452, P < .001, and rs = -0.301, P = .010, respectively). CONCLUSION: The KPR is a simple and practical tool to determine whether it is appropriate for a child or adolescent with concussion to commence graded exercise.

Changes in Bench Press Velocity and Power After 8 Weeks of High-Load Cluster- or Traditional-Set Structures.

Davies, TB, Halaki, M, Orr, R, Helms, ER, and Hackett, DA. Changes in bench press velocity and power after 8 weeks of high-load cluster- or traditional-set structures. J Strength Cond Res 34(10): 2734-2742, 2020-This study investigated the effects of high-load cluster- vs. traditional-set structures using the bench press on velocity and power. Twenty-one resistance-trained individuals (male = 12, female = 9) performed a 3-week familiarization block followed by randomization into 1 of 2 upper- and lower-body split training routines performed for 8 weeks. The bench press was the only exercise manipulated with subjects using either cluster-set (CLUS, n = 11) or traditional-set (TRAD, n = 10) structures during training sessions. Subjects performed 4 sets of 5 repetitions at 85% 1 repetition maximum (1RM) with CLUS having a 30-second inter-repetition, and 3-minute interset rest while TRAD had a 5-minute interset rest. A load-velocity profile of relative loads derived from a 1RM test was used to assess velocity and power (absolute and relative to body mass) on the bench press. Significant improvements over time were found across various loads ranging from 45 to 75% 1RM for absolute and relative peak power (p = 0.006-0.041), and mean power (p = 0.001-0.032). Significant decreases over time were found at 55% 1RM and 65% 1RM for peak velocity (p = 0.027 and p = 0.012, respectively) and mean velocity (p = 0.047 and p = 0.022, respectively). There were no significant group or group by time interactions found for all outcomes. Within the context of high-load resistance training, set structure seems to be of less importance for changes in bench press velocity and power provided there is an intention to lift with maximal concentric velocity.

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

OBJECTIVE: To systematically review the literature to investigate the potential relationship between neck strength and head acceleration during purposeful heading in soccer. DESIGN: Systematic review. METHODS: Comprehensive search of five electronic databases: EMBASE, MEDLINE, CINAHL, SportsDiscus and Web of Science. Studies were included if they reported data on the relationship between neck strength and head impact and/or acceleration during purposeful soccer heading, published in English (or translation available). RESULTS: From an initial search of 1174 potentially eligible papers, five cross-sectional studies met the eligibility criteria for inclusion in this review. Data from cross-sectional studies indicate that higher neck strength is associated with lower head acceleration during purposeful heading in soccer (p=<0.05; r<-0.5). CONCLUSION: This review provides evidence that higher neck strength may lower head acceleration during purposeful heading in soccer. Further research is required to determine the most effective method to strengthen the neck musculature in soccer players.

Movement Demands of Rugby Sevens in Men and Women: A Systematic Review and Meta-Analysis.

Ball, S, Halaki, M, and Orr, R. Movement demands of rugby sevens in men and women: A systematic review and meta-analysis. J Strength Cond Res 33(12): 3475-3490, 2019-Global positioning systems (GPS) provide comprehensive information of player movement demands in rugby 7's. Although studies have investigated the use of GPS within many field-based team sports, the application of GPS within rugby 7's remains unclear. The aim of this review was to evaluate the movement demands and conduct a meta-analysis on comparable GPS measures to assess player movement in rugby 7's. A systematic search of electronic databases Medline, SPORTDiscus, Cinahl, Web of Science, Scopus, and Embase was performed. The search strategy combined terms covering: global positioning systems AND rugby union. Studies were included if they contained rugby sevens' players monitored by GPS. Meta-analyses were conducted to provide a pooled mean and confidence intervals (CIs) on outcomes for data extracted from at least 3 studies. A total of 24 publications were eligible for review and included 661 (447 male and 214 female) rugby 7's players. Meta-analysis indicated that male players cover greater relative distance (male: 108.5 m·min, 95% CI [104.9-112.1] m·min, female: 100.3 m·min, 95% CI [96.0-104.7] m·min), distance at >12.6 km·h (male: 449.3 m, 95% CI [427.0-471.5] m, female: 339.5 m, 95% CI [291.1-387.9] m) and >18.0 km·h (male: 190.3 m, 95% CI [180.7-199.9] m, female: 129.9 m, 95% CI [99.9-159.8] m), and have a greater maximum velocity compared with female players (male: 29.8 km·h, 95% CI [29.2-30.4] km·h, female: 24.6 km·h, 95% CI [23.3-25.9] km·h), whereas relative distance is higher for the first half (109.5 m·min, 95% CI [99.1-120.0] m·min) compared with the second half (93.8 m·min, 95% CI [87.4-100.1] m·min) of match play across sexes and playing levels. Independent velocity zone classifications should apply for male and female players, whereas velocity thresholds should remain consistent across studies. Rugby 7's training intensity should vary between male and female players.

The Role of Aerobic Exercise in Reducing Persistent Sport-related Concussion Symptoms.

Aerobic exercise has received increasing attention in the scientific literature as a component of management for individuals who sustain a concussion. Because exercise training has been reported to reduce symptoms and improve function for those experiencing persistent postconcussion symptoms, it represents a potentially useful and clinically pragmatic rehabilitation technique. However, the specific exercise parameters that best facilitate recovery from concussion remain poorly defined and unclear. This review will provide a summary of the current understanding of the role of subsymptom exercise to improve outcomes after a concussion and will describe the exercise parameters that appear to be important. The latter will take into account the three pillars of exercise dose-frequency, duration, and intensity-to examine what is currently known. In addition, we identify important gaps in our knowledge of exercise as a treatment for those who develop persistent symptoms of concussion.

Australian athletes' knowledge of the WADA Prohibited Substances List and performance enhancing substances.

BACKGROUND: This study investigated athlete knowledge of the World Anti-doping Agency (WADA) Prohibited Substances List and the effects of four well-known performance enhancing substances (PES). METHODS: A sample of 1925 elite and sub-elite athletes (mean age 20.6 years) completed a questionnaire about the banned status of 30 substances/methods and their knowledge of the effects of amphetamines, anabolic steroids, growth hormone and erythropoietin. RESULTS: Athletes showed limited understanding of the WADA Prohibited Substances List, scoring 32.2% correct, 36.3% incorrect, and 31.4% indicated they did not know the status of 30 substances. Responses of >50% correct were given for only eight substances/method: anabolic steroids, amphetamines, blood doping, erythropoietin, caffeine, vitamins/minerals, protein powders and iron. Athletes demonstrated moderate knowledge of the desired effects of the four PES (49% correct), but poor knowledge of their adverse effects (29% correct). Age, sex, ethnicity, professional/amateur status, and current competition level were significant predictors of the number of correct responses (r2 = 0.16, p < 0.05). Athletes most likely to provide correct responses were male, 19-22 year-olds, Caucasian, professional and international representatives. CONCLUSION: This comprehensive study of anti-doping demonstrated that Australian athletes had limited knowledge of a wide range of substances and PES. Better targeted drug education towards younger and non-professional athletes and evaluation of current anti-doping programs are warranted.