Objective Measures of Strain and Subjective Muscle Soreness Differ Between Positional Groups and Season Phases in American College Football.

PURPOSE: To assess objective strain and subjective muscle soreness in "Bigs" (offensive and defensive line), "Combos" (tight ends, quarterbacks, line backers, and running backs), and "Skills" (wide receivers and defensive backs) in American college football players during off-season, fall camp, and in-season phases. METHODS: Twenty-three male players were assessed once weekly (3-wk off-season, 4-wk fall camp, and 3-wk in-season) for hydroperoxides (free oxygen radical test [FORT]), antioxidant capacity (free oxygen radical defense test [FORD]), oxidative stress index (OSI), countermovement-jump flight time, Reactive Strength Index (RSI) modified, and subjective soreness. Linear mixed models analyzed the effect of a 2-within-subject-SD change between predictor and dependent variables. RESULTS: Compared to fall camp and in-season phases, off-season FORT (P ≤ .001 and <.001), FORD (P ≤ .001 and <.001), OSI (P ≤ .001 and <.001), flight time (P ≤ .001 and <.001), RSI modified (P ≤ .001 and <.001), and soreness (P ≤ .001 and <.001) were higher for "Bigs," whereas FORT (P ≤ .001 and <.001) and OSI (P = .02 and <.001) were lower for "Combos." FORT was higher for "Bigs" compared to "Combos" in all phases (P ≤ .001, .02, and .01). FORD was higher for "Skills" compared with "Bigs" in off-season (P = .02) and "Combos" in-season (P = .01). OSI was higher for "Bigs" compared with "Combos" (P ≤ .001) and "Skills" (P = .01) during off-season and to "Combos" in-season (P ≤ .001). Flight time was higher for "Skills" in fall camp compared with "Bigs" (P = .04) and to "Combos" in-season (P = .01). RSI modified was higher for "Skills" during off-season compared with "Bigs" (P = .02) and "Combos" during fall camp (P = .03), and in-season (P = .03). CONCLUSION: Off-season American college football training resulted in higher objective strain and subjective muscle soreness in "Bigs" compared with fall camp and during in-season compared with "Combos" and "Skills" players.

Subjective Measures of Workload and Sleep in Australian Army Recruits; Potential Utility as Monitoring Tools.

INTRODUCTION: Subjective measures may offer practitioners a relatively simple method to monitor recruit responses to basic military training (BMT). Yet, a lack of agreement between subjective and objective measures may presents a problem to practitioners wishing to implement subjective monitoring strategies. This study therefore aims to examine associations between subjective and objective measures of workload and sleep in Australian Army recruits. MATERIALS AND METHODS: Thirty recruits provided daily rating of perceived exertion (RPE) and differential RPE (d-RPE) for breathlessness and leg muscle exertion each evening. Daily internal workloads determined via heart rate monitors were expressed as Edwards training impulse (TRIMP) and average heart rate. External workloads were determined via global positioning system (PlayerLoadTM) and activity monitors (step count). Subjective sleep quality and duration was monitored in 29 different recruits via a customized questionnaire. Activity monitors assessed objective sleep measures. Linear mixed-models assessed associations between objective and subjective measures. Akaike Information Criterion assessed if the inclusion of d-RPE measures resulted in a more parsimonious model. Mean bias, typical error of the estimate (TEE) and within-subject repeated measures correlations examined agreement between subjective and objective sleep duration. RESULTS: Conditional R2 for associations between objective and subjective workloads ranged from 0.18 to 0.78, P < 0.01, with strong associations between subjective measures of workload and TRIMP (0.65-0.78), average heart rate (0.57-0.73), and PlayerLoadTM (0.54-0.68). Including d-RPE lowered Akaike Information Criterion. The slope estimate between objective and subjective measures of sleep quality was not significant. A trivial relationship (r = 0.12; CI -0.03, 0.27) was observed between objective and subjective sleep duration with subjective measures overestimating (mean bias 25 min) sleep duration (TEE 41 min). CONCLUSIONS: Daily RPE offers a proxy measure of internal workload in Australian Army recruits; however, the current subjective sleep questionnaire should not be considered a proxy measure of objective sleep measures.

Injury incidence and burden differ between season phases in male academy football (soccer) players.

Adolescent elite-level footballers are exposed to unique physical and psychological stressors which may increase injury risk, with fluctuating injury prevalence and burden. This study investigates the patterns of injury incidence and burden from 2017 to 2020 within combined pre-, start-of-, mid- and end-of-season and school-holiday phases in U13-U18 Australian male academy players. Injury incidence rate and burden were calculated for medical attention (MA), full and partial time-loss (TL) and non-time-loss (non-TL) injuries. Injury rate ratios (IRR) for injury incidences were assessed using Generalised Linear Mixed Models, and 99% confidence intervals for injury burden differences between phases. MA and non-TL injury incidence rates were higher during pre-season (IRR 1.65, p = 0.01; IRR 2.08, p = 0.02, respectively), and mid-season showed a higher non-TL incidence rate (IRR 2.15, p = 0.02) and burden (69 days with injury/1000 hrs, CI 47-103) compared to end-of-season (25 days with injury/1000 hrs, CI 15-45). MA injury rates and partial TL injury burden were higher during school compared to holiday periods (IRR 0.6, p = 0.04; 61 partial days lost/1000 hrs, CI 35-104; 13 partial days lost/1000 hrs, CI 8-23). Season phase and return-to-school may increase injury risks for elite academy footballers, and considering these phases may assist in developing injury prevention systems.

Exploring the true burden of a time-loss injury: full vs partial time-loss in elite academy football (soccer).

In football, the number of days without full participation in training/competition is often used as a surrogate measure for time-loss (TL) caused by injury. However, injury management and return-to-play processes frequently include modified participation, which to date has only been recorded through self-reports. This study aims to demonstrate the differentiation between 'full' (no participation in team football) and 'partial' (reduced/modified participation in team football) burden. Injury and exposure data were collected from 118 male elite footballers (U13-U18) over 3 consecutive seasons according to the Football Consensus Statement. TL injury burden was calculated separately as the number of total, 'full' and 'partial' days lost per 1000 h of exposure. Injury burden (137.2 days lost/1000 h, 95% CI 133.4-141.0) was comprised of 23% (31.9 days lost/1000 h, 95% CI 30.1-33.8) partial TL and 77% (105.3 days lost/1000 h, 95% CI 102.0-108.6) full TL burden. Injuries of moderate severity (8-28 days lost) showed 40% of partial TL. TL injury incidence rate (6.6 injuries/1000 h, 95% CI 5.8-7.5), the number of severe injuries (16%), and the distribution of TL and non-TL injuries (56% and 44%) were comparable to other reports in elite youth footballers. Almost one-quarter of the TL injury burden showed that injured players were still included in some team football activities, which, for injuries with TL >7 days, was likely related to the return to play process. Therefore, reporting on partial TL provides insight into the true impact of injury on participation levels.

A Comprehensive Analysis of Injuries During Army Basic Military Training.

INTRODUCTION: The injury definitions and surveillance methods commonly used in Army basic military training (BMT) research may underestimate the extent of injury. This study therefore aims to obtain a comprehensive understanding of injuries sustained during BMT by employing recording methods to capture all physical complaints. MATERIALS AND METHODS: Six hundred and forty-six recruits were assessed over the 12-week Australian Army BMT course. Throughout BMT injury, data were recorded via (1) physiotherapy reports following recruit consultation, (2) a member of the research team (third party) present at physical training sessions, and (3) recruit daily self-reports. RESULTS: Two hundred and thirty-five recruits had ≥1 incident injury recorded by physiotherapists, 365 recruits had ≥1 incident injury recorded by the third party, and 542 recruits reported ≥1 injury-related problems via the self-reported health questionnaire. Six hundred twenty-one, six hundred eighty-seven, and two thousand nine hundred sixty-four incident injuries were recorded from a total of 997 physiotherapy reports, 1,937 third-party reports, and 13,181 self-reported injury-related problems, respectively. The lower extremity was the most commonly injured general body region as indicated by all three recording methods. Overuse accounted for 79% and 76% of documented incident injuries from physiotherapists and the third party, respectively. CONCLUSIONS: This study highlights that injury recording methods impact injury reporting during BMT. The present findings suggest that traditional injury surveillance methods, which rely on medical encounters, underestimate the injury profile during BMT. Considering accurate injury surveillance is fundamental in the sequence of injury prevention, implementing additional injury recording methods during BMT may thus improve injury surveillance and better inform training modifications and injury prevention programs.

Monitoring work and training load in military settings - what's in the toolbox?

Military personnel are required to complete physically demanding tasks when performing work and training, which may be quantified through the physical stress imposed (external load) or the resultant physiological strain (internal load). The aim of this narrative review is to provide an overview of the techniques used to monitor work and training load in military settings, summarise key findings, and discuss important practical, analytical, and conceptual considerations. Most investigations have focused upon measuring external and internal load in military training environments; however, limited data exist in operational settings. Accelerometry has been the primary tool used to estimate external load, with heart rate commonly used to quantify internal load. Supplemental to heart rate, psychophysiological and biochemical measures have also been investigated to elucidate aspects of internal load. Broadly, investigations have revealed that military training requires personnel to perform relatively large volumes of physical activity (e.g. averaging ∼15,000 steps·day-1) of typically low-moderate intensity activity (<6 MET), although considerable temporal and inter-individual variability is observed from these gross mean estimates. There are limitations associated with these measures and, at best, estimates of external and internal load can only be inferred. These limitations are particularly pertinent for military tasks such as load carriage and manual material handling, which often involve complex activities performed individually or in teams, in a range of operational environments, with multiple layers of protection, over a protracted duration. Comprehensively quantifying external and internal loads during these functional activities poses substantial practical and analytical challenges.

Comparison of player-dependent and independent high-speed running thresholds to model injury risk in football.

High-speed running (HSR) loads have been linked with non-contact injury risks in team-sports. This study investigated whether player-specific speed zones, reflecting individual fitness characteristics, impact the associations between non-contact injury and acute and chronic HSR loads. Semi-professional soccer players from two clubs (n = 47) were tracked over two seasons using 10 Hz GPS (5552 observations). HSR distances were calculated arbitrarily (≥5.5 m·s-1), and in an individualised fashion based on the final speed of the 30-15 intermittent fitness test. Cumulative running loads were represented by exponentially weighted moving averages with 7-(acute) and 28-day (chronic) decay parameters. Physiotherapists collected non-contact, lower-limb, time-loss injury data (n = 101). Injury models using session type (training vs matches), coach, as well as arbitrary or individualised running loads were constructed via mixed-effect logistic regression. Session type had the largest effect on injury (training vs match OR = 0.28; 95%CI:0.17-0.44). Variations in individualised or arbitrary acute and chronic HSR loads within the mid-range of the observed data had negligible effects on predicted injury risk. However, the uncertainty of estimated effects at extreme values of acute and chronic HSR loads prevented any conclusive findings. Therefore, the efficacy of using customised speed thresholds in quantifying load for injury risk mitigation purposes remains unclear.

The Association Between Alterations in Redox Homeostasis, Cortisol, and Commonly Used Objective and Subjective Markers of Fatigue in American Collegiate Football.

PURPOSE: To assess associations between a free oxygen radical test (FORT), free oxygen radical defense test (FORD), oxidative stress index, urinary cortisol, countermovement jump (CMJ), and subjective wellness in American college football. METHODS: Twenty-three male student athlete American college football players were assessed over 10 weeks: off-season conditioning (3 wk), preseason camp (4 wk), and in season (3 wk). Assessments included a once-weekly FORT and FORD blood sample, urinary cortisol sample, CMJ assessment including flight time, reactive strength index modified and concentric impulse, and a daily subjective wellness questionnaire. Linear mixed models analyzed the effect of a 2 within-subject SD change in the predictor variable on the dependent variable. The effects were interpreted using magnitude-based inference and are presented as standardized effect size (ES) ± 90% confidence intervals. RESULTS: Small negative associations were observed between FORT-flight time, FORT-fatigue, FORT-soreness (ES range = -0.30 to -0.48), FORD-sleep (ES = 0.42 ± 0.29), and oxidative stress index soreness (ES = 0.56 ± 0.29). Small positive associations were observed between FORT-cortisol (ES = 0.36 ± 0.35), FORD-flight time, FORD reactive strength index modified and FORD-soreness (0.37-0.41), oxidative stress index concentric impulse (ES = 0.37 ± 0.28), and with soreness-concentric impulse, soreness-flight time, and soreness reactive strength index modified (0.33-0.59). Moderate positive associations were observed between cortisol-concentric impulse and cortisol-sleep (0.57-0.60). CONCLUSION: FORT/FORD was associated with CMJ variables and subjective wellness. Greater amounts of subjective soreness were associated with decreased CMJ performance, increased FORT and cortisol, and decreased FORD.

Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players: a one-club matched-paired randomised controlled trial.

Background:Although the 11+ is known to reduce injuries and improve performance in adolescent footballers, its duration presents a notable barrier to implementation. Hence, this study investigated injury and performance outcomes when 65 elite male academy footballers either performed Part 2 3x/week at training (TG) or at home (HG).Methods:Time to stabilisation (TTS), eccentric hamstring strength (EH-S) and countermovement jump height (CMJ-H) were collected 4 times during the 2019 football season. Linear mixed models were used to evaluate main and interaction effects of group and time. Bonferroni post-hoc tests were used to account for multiple comparisons. Differences in time loss and medical attention injuries were determined using a two-tailed Z test for a comparison of rates.Results:Relative to baseline, EH-S (HG 4.3 kg, 95% CI 3 to 5.7, p < 0.001; TG 5.5 kg, 95% CI 4.3 to 6.6, p < 0.001) and CMJ-H (HG 3.5 cm, 95% CI 2.2 to 4.7, p < 0.001; TG 3.2 cm, 95% CI 2.2 to 4.3, p < 0.001) increased, with no difference between groups observed at the end of the season. All injury outcomes were similar.Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers.

A pilot study using a small-sided games program to modify cardiovascular health in sedentary Indigenous men.

ISSUES ADDRESSED: To determine cardiovascular health benefits in Indigenous men following short-duration small-sided games. METHODS: Fourteen sedentary Indigenous males (35.6 SD 7.2 years), randomly assigned to a small-sided games (SSG) or a non-exercising control. Small-sided 20-minute (4 × 5 minute bouts) games of touch football were played 2 x/week for 9 weeks. Waist and hip circumferences, height, total body mass (kg), fat (%), fat free mass (kg), muscle mass (kg), resting heart rate (bpm), systolic blood pressure (mmHg), total cholesterol and high-density lipid concentrations were measured and waist-hip ratios, body mass index (BMI), heart rate variability (HRV), metabolic age and Framingham risk calculated before and after the exercise intervention. Between group differences were examined using unpaired t tests (welch corrected) and described using Cohen's effect size (ES) differences (corrected to determine hedges g). RESULTS: Significant between group differences favouring the SSG group were observed in body mass (P = .039, ES = 0.18), BMI (P = .031, ES = 0.22) and metabolic age (P = .033, ES = 0.29) and in HRV parameters of approximate entropy (ApEN; P = .01, ES = 1.65) and sample entropy (SampEN; P = .0193, ES = 1.40). CONCLUSION: Middle-aged Indigenous men can gain cardiovascular health benefits following short bouts of small-sided game play accumulating in 40-minutes of exercise each week. SO WHAT?: Short-duration SSG may address many exercise barriers, and offer a sustainable form of exercise to improve cardiovascular health amongst Indigenous men.

Influence of Training Schedules on Objective Measures of Sleep in Adolescent Academy Football Players.

Brown, GA, Veith, S, Sampson, JA, Whalan, M, and Fullagar, HHK. Influence of training schedules on objective measures of sleep in adolescent academy football players. J Strength Cond Res 34(9): 2515-2521, 2020-Football academy settings may pose risks to adolescent athletes achieving sufficient sleep because of the contextual challenges these players face (e.g., psychosocial pressure, changes in training, competition, and academic stress). Given the importance of sleep to overall health as well as physical athletic development and injury risk, this study aimed to investigate whether differences in training schedules (morning vs. evening training sessions) affected objective measures of sleep in adolescent academy football (soccer) players. Twelve academy players (mean age 14.18 ± 1.36 years) wore an ActiGraph accelerometer on nights before, and nights of, training days in 2 separate weeks where morning (09:00-11:00 hours) and evening (18:00-20:00 hours) training occurred. Objective sleep parameters and training load data were collected. Night-time sleep periods were categorized as sleep preceding morning training, preceding evening training, or after evening training. One-way univariate and multivariate analyses of variance for repeated measures were performed to determine the impact of the training schedule on sleep. Significance levels were set at p < 0.05. The total sleep time was below the recommended guidelines (<8 hours) across conditions. A large significant effect of the training schedule on time attempted to fall asleep (p = 0.004, effect size [ES] = 0.40) and time of sleep (p = 0.003, ES = 0.41) was present, with post-evening sessions resulting in the latest times. Overall, the players' sleep behavior was resilient to changes in training schedules. However, the low sleep durations (and potential risks to physical performance/injury) suggest that sleep education coupled with practical interventions are required in this cohort.

Effect of a novel low volume, high intensity concurrent training regimen on recruit fitness and resilience.

OBJECTIVES: To determine the effect of a novel low volume high intensity concurrent training regimen and warm-up on physiological performance and musculoskeletal injury in Australian recruits. DESIGN: Controlled longitudinal intervention. METHODS: Military recruits completed 12 weeks of either experimental (EXP: n=78, 6-8RM resistance loads, and high intensity intervals) or basic military (CON: n=69, usual practice) matched for total sessions and time. Endurance (3.2km 22kg-load carriage, V˙O2 peak, multi-stage fitness test (MSFT)), 1RM strength and local muscle endurance (bench, squat, box-lift and push-ups) and power (squat jump) were assessed at Weeks 1,6,12. Body composition, physical activity (PAC·min-1) and heart rate reserve (HRR%), were assessed at Weeks 2,7,9. Musculoskeletal injury and mechanism were recorded. Two-way repeated measures ANOVA interaction (group×time), mean difference and effect size (ES) are reported p≤0.05. RESULTS: A significant interaction over 12 weeks was observed for load carriage (ES -0.30), squat jump (ES 0.65), V˙O2 peak (ES 0.58), MSFT (ES 0.41), push-ups (ES 0.26), 1RM bench (ES 0.26), squat (ES 1.05) and box lift (ES 0.27) in EXP compared to CON. At Week 12 significantly greater squat (38.9kg), MSFT (2.1mL·kg-1·min-1), and faster load carriage (49.9s) was observed in EXP than CON, but no difference in body composition. EXP had a lower PAC·min-1 (641.1±63.1) but higher HRR% (21.8±4.0) compared to CON. EXP had a lower number of injuries (6) compared to CON (17). CONCLUSIONS: The inclusion of compound-specific resistance exercise and high intensity intervals improved physical function and was associated with reduced musculoskeletal injury.

"How Am I Going, Coach?"-The Effect of Augmented Feedback During Small-Sided Games on Locomotor, Physiological, and Perceptual Responses.

PURPOSE: To investigate whether providing global positioning system feedback to players between bouts of small-sided games (SSGs) can alter locomotor, physiological, and perceptual responses. METHODS: Using a reverse counterbalanced design, 20 male university rugby players received either feedback or no feedback during "off-side" touch rugby SSGs. Eight 5v5, 6 × 4-minute SSGs were played over 4 d. Teams were assigned to a feedback or no-feedback condition (control) each day, with feedback provided during the 2-min between-bouts rest interval. Locomotor, heart rate, and differential rating of perceived exertion of breathlessness and leg-muscle exertion were measured and analyzed using a linear mixed model. Outcomes were reported using effect sizes (ES) and 90% confidence intervals (CI), and then interpreted via magnitude-based decisions. RESULTS: Very likely trivial to unclear differences at all time points were observed in heart rate and differential rating of perceived exertion measures. Possibly to very likely trivial effects were observed between conditions, including total distance (ES = 0.15; 90 CI, -0.03 to 0.34), high-speed distance (ES = -0.07; 90 CI, -0.27 to 0.13), and maximal sprint speed (ES = 0.11; 90% CI, -0.11 to 0.34). All within-bout comparisons showed very likely to unclear differences, apart from possible increases in low-speed distance in bout 2 (ES = 0.23; 90% CI, 0.01 to 0.46) and maximal sprint speed in bout 4 (ES = 0.21; 90% CI, -0.04 to 0.45). CONCLUSIONS: In this study, verbal feedback did not alter locomotor, physiological, or perceptual responses in rugby players during SSGs. This may be due to contextual factors (eg, opposition) or the type (ie, distance) or low frequency of feedback provided.

Rescheduling Part 2 of the 11+ reduces injury burden and increases compliance in semi-professional football.

Although the 11+ program has been shown to reduce injuries in sub-elite football, program compliance is typically poor, suggesting that strategies to optimize delivery are necessary. This study investigated the effect of rescheduling Part 2 of the three-part 11+ program on program effectiveness. Twenty-five semi-professional football clubs were randomly allocated to either a Standard-11+ (n = 398 players) or P2post group (n = 408 players). Both groups performed the 11+ program at least twice a week throughout the 2017 football season. The Standard-11+ group performed the entire 11+ program before training activities commenced, whereas the P2post group performed Parts 1 and 3 of the 11+ program before and Part 2 after training. Injuries, exposure, and individual player 11+ dose were monitored throughout the season. No significant between group difference in injury incidence rate (P2pos t vs Standard-11+ = 11.8 vs 12.3 injuries/1000 h) was observed. Severe time loss injuries > 28 days (33 vs 58 injuries; P < .002) and total days lost to injury (4303 vs 5815 days; P < .001) were lower in the P2post group. A higher 11+ program dose was observed in the P2post (29.1 doses; 95% CI 27.9-30.1) versus Standard-11+ group (18.9 doses; 95% CI 17.6-20.2; P < .001). In semi-professional football, rescheduling Part 2 of the 11+ program to the end of training maintained the effectiveness of the original 11+ program to reduce injury incidence. Importantly, rescheduling Part 2 improved player compliance and reduced the number of severe injuries and total injury burden, thereby enhancing effectiveness of the 11+ program.

Subjective Wellness, Acute: Chronic Workloads, and Injury Risk in College Football.

Sampson, JA, Murray, A, Williams, S, Sullivan, A, and Fullagar, HHK. Subjective wellness, acute: chronic workloads and injury risk in college football. J Strength Cond Res 33(12): 3367-3373, 2019-Acute:chronic workload ratios (ACWRs) are associated with injury risk across team sports. In this study, one season of workload and wellness data from 42 collegiate football players were retrospectively analyzed. Daily 7:21 day exponentially weighted moving average (EWMA) ACWRs were calculated, and z-score fluctuations ("normal," "better," and "worse") in sleep, soreness, energy, and overall wellness were assessed relative to the previous day ACWRs and considered as an interactive effect on the risk of noncontact injury within 0-3 days. Fifty-five noncontact injuries were observed, and injury risks were very likely higher when ACWRs were 2 SDs above (relative risk [RR]: 3.05, 90% confidence interval [CI]: 1.14-8.16) and below (RR: 2.49, 90% CI: 1.11-5.58) the mean. A high ACWR was trivially associated (p < 0.05) with "worse" wellness (r = -0.06, CI: -0.10 to -0.02), muscle soreness (r = -0.07, CI: -0.11 to -0.03), and energy (r = -0.05, CI: -0.09 to -0.01). Feelings of "better" overall wellness and muscle soreness with collectively high EWMA ACWRs displayed likely higher injury risks compared with "normal" (RR: 1.52, 90% CI: 0.91 to 2.54; RR: 1.64, 90% CI: 1.10-2.47) and likely or very likely (RR: 2.36, 90% CI: 0.83 to 674; RR: 2.78, 90% CI: 1.21-6.38) compared with "worse" wellness and soreness, respectively. High EWMA ACWRs increased injury risk and negatively impacted wellness. However, athletes reporting "better" wellness, driven by "better" muscle soreness presented with the highest injury risk when high EWMA ACWRs were observed. This suggests that practitioners are responsive to, and/or athletes are able to self-modulate workload activities.

The incidence and burden of time loss injury in Australian men's sub-elite football (soccer): A single season prospective cohort study.

OBJECTIVES: This study aimed to conduct the first injury surveillance study in sub-elite football in Australia, using methods from the international football consensus statement. DESIGN: Descriptive epidemiological study. METHODS: 1049 sub-elite football players were recruited during the 2016 season. Injury and exposure data was collected by trained Primary Data Collectors (PDCs) who attended every training session and match. RESULTS: There were 1041 time loss injuries recorded during 52,127h of exposure resulting in an injury incidence rate of 20 injuries/1000h (95% Confidence Interval [CI]: 15.9-23.3). The injury burden (days lost to injury relative to exposure) was 228days lost/1000h. Muscle and ligament injuries were the most prevalent (41% and 26%) and incurred the highest injury burden (83 and 80days lost/1000h, respectively). The most common injuries were observed at the thigh (22%) and ankle (17%), with hamstring (13%) the highest reported muscle injury. The profile of injury severity was: mild - 35%; minor - 29%; moderate - 28% and severe - 8%. Recurrent injuries accounted for 20% of all injuries. CONCLUSIONS: By addressing issues identified with injury recording in sub-elite football, this study found that the injury incidence was twice that observed in previous research in elite and sub-elite football cohorts. Injury burden was also twice that of the elite setting, with similar injuries associated with the highest burden. The results highlight the need for investment into medical provision, facilities, coach education and injury mitigation programmes to reduce healthcare costs to sub-elite players in Australia.

Positive, limited and negative responders: The variability in physical fitness adaptation to basic military training.

OBJECTIVES: To investigate the heterogeneity of physical adaptation in Australian Army recruits completing a 12-week basic military training regimen. DESIGN: A prospective research design. METHODS: Volunteer recruits (n=195) completed 12-weeks of basic military training. Recruit physical fitness was assessed at week 1, weeks 6-8 and week 12. Recruits in the upper (75th) and lower (25th) quartiles for each assessment were then analysed using a repeated measures two-way ANOVA. The relative magnitude of recruit adaptions were classified as positive response (Rpositive, ≥5%), limited response (Rlimited, >-5% to <5%) and negative response (Rnegative, ≤-5%); Chi-square analysis determined the proportional differences in the distribution of each quartile. RESULTS: An interaction (p<0.001) was observed in the lower and upper recruit quartiles for all assessments of physical fitness at each time point. After 12 weeks of military training the mean difference of the highest quartile was; 20-m multi-stage fitness test 7.4mL·kg-1·min-1, (CI:5.8:9.1), 2-min push-ups 20.1 reps, (CI:16.2:23.9), 1RM box lift 5.6kg, (CI:2.6:5.8) and load carriage 222.1s, (CI:174.7:269.4) compared to the lowest recruit quartile. The highest quartile demonstrated no improvement in 1RM box lift (-4%, -1%) and push-ups (2%, 0%) performance at weeks 6-8 and week 12 respectively. In contrast, adaptations in the lowest quartile for 1RM box lift (16%, 21%) and push-ups (46%, 46%) over the same time periods were observed. CONCLUSIONS: A significant proportion of recruits may complete basic military training with a decline in physical performance. Higher relative-intensity cardiorespiratory and resistance exercise should be considered to facilitate physical adaptation in all recruits.

Soccer Injury Movement Screen (SIMS) Composite Score Is Not Associated With Injury Among Semiprofessional Soccer Players.

Background The association between movement quality and injury is equivocal. No soccer-specific movement assessment has been prospectively investigated in relation to injury risk. Objectives To investigate the association between a soccer-specific movement-quality assessment and injury risk among semiprofessional soccer players. Methods In this prospective cohort study, semiprofessional soccer players (n = 306) from 12 clubs completed the Soccer Injury Movement Screen (SIMS) during the preseason period. Individual training/match exposure and noncontact time-loss injuries were recorded prospectively for the entirety of the 2016 season. Relative risks were calculated, and presented with 90% confidence intervals, for the SIMS composite and individual subtest scores from generalized linear models with Poisson distribution offset for exposure. Results When considering noncontact time-loss lower extremity injuries (primary level of analysis), there was a most likely trivial association with the SIMS composite score. Similarly, the SIMS composite score demonstrated most likely to likely trivial associations with all injury categories included in the secondary level of analysis (noncontact time-loss hip/groin, thigh, knee, and ankle injuries). When considering hamstring strains and ankle sprains specifically (tertiary level of analysis), the SIMS composite score demonstrated very likely trivial associations. A total of 262 noncontact time-loss injuries were recorded. The overall (training and match exposure combined) incidence of noncontact time-loss injury was 12/1000 hours. Conclusion The SIMS composite score demonstrated no association with any of the investigated categories of soccer-related injury. The SIMS composite score should not be used to group players into high- or low-risk groups. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2018;48(8):630-636. Epub 8 May 2018. doi:10.2519/jospt.2018.8037.

Effect of Practice on Performance and Pacing Strategies During an Exercise Circuit Involving Load Carriage.

Burdon, CA, Park, J, Tagami, K, Groeller, H, and Sampson, JA. Effect of practice on performance and pacing strategies during an exercise circuit involving load carriage. J Strength Cond Res 32(3): 700-707, 2018-Pacing is critical for athletic endeavors, and the strategies used by athletes are often modified after practice. The importance of practice when completing occupational assessments has been established; however, the effect of load carriage and discrete subtask activities on strategies to modulate physical exertion to complete a work task simulation is currently unknown. Therefore, we sought to investigate the effect of practice on pacing strategies used to complete a physiological aptitude assessment circuit. Twenty-five participants completed an assessment designed for firefighters on 3 occasions. The circuit comprised 6 disparate tasks (including unilateral load carriage, static holds and fire-hose drags) with lap and task completion times recorded. Pacing strategies were examined relative to the effect of practice throughout (globally) and within the assessment (discrete tasks). By the second visit, overall test performance and discrete task performance of the first, fourth, and fifth tasks improved, respectively, by 12.6% (95% confidence interval: ±3.6%, p < 0.01), 12.4% (±6.0%, p < 0.01), 11.7% (±4.9%, p < 0.01), and 17.8% (±10.0%, p < 0.03). Compared with visit 1, significant improvements in performance were observed on the second and third visit. However, no significant additional improvement was noted between visits 2 and 3. Therefore, to reliably assess performance of the occupational test, 1 practice session (2 visits) is required. Practice is important to allow individuals to optimize their pacing strategy for successful performance.

The Influence of Playing Experience and Position on Injury Risk in NCAA Division I College Football Players.

PURPOSE: American football is widely played by college student-athletes throughout the United States; however, the associated injury risk is greater than in other team sports. Numerous factors likely contribute to this risk, yet research identifying these risk factors is limited. The present study sought to explore the relationship between playing experience and position on injury risk in NCAA Division I college football players. METHODS: Seventy-six male college student-athletes in the football program of an American NCAA Division I university participated. Injuries were recorded over 2 consecutive seasons. Players were characterized based on college year (freshman, sophomore, junior, or senior) and playing position. The effect of playing experience and position on injury incidence rates was analyzed using a generalized linear mixed-effects model, with a Poisson distribution, log-linear link function, and offset for hours of training exposure or number of in-game plays (for training and game injuries, respectively). RESULTS: The overall rates of non-time-loss and time-loss game-related injuries were 2.1 (90% CI: 1.8-2.5) and 0.6 (90% CI: 0.4-0.8) per 1000 plays, respectively. The overall rates of non-time-loss and time-loss training-related injuries were 26.0 (90% CI: 22.6-29.9) and 7.1 (90% CI: 5.9-8.5) per 1000 h, respectively. During training, seniors and running backs displayed the greatest risk. During games, sophomores, juniors, and wide receivers were at greatest risk. CONCLUSIONS: Being aware of the elevated injury risk experienced by certain player groups may help coaches make considered decisions related to training design and player selection.