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Objective: To investigate the association between the acute:chronic workload ratio (ACWR) and running-related injuries (RRI). Methods: This is a secondary analysis using a database composed of data from three studies conducted with the same RRI surveillance system. Longitudinal data comprising running exposure (workload) and RRI were collected biweekly during the respective cohorts' follow-up (18–65 weeks). ACWR was calculated as the most recent (i.e., acute) external workload (last 2 weeks) divided by the average external (i.e., chronic) workload of the last 4, 6, 8, 10 and 12 weeks. Three methods were used to calculate the ACWR: uncoupled, coupled and exponentially weighted moving averages (EWMA). Bayesian logistic mixed models were used to analyse the data. Results: The sample was composed of 435 runners. Runners whose ACWR was under 0.70 had about 10% predicted probability of sustaining RRI (9.6%; 95% credible interval [CrI] 7.5–12.4), while those whose ACWR was higher than 1.38 had about 1% predicted probability of sustaining RRI (1.3%; 95% CrI 0.7–1.7). The association between the ACWR and RRI was significant, varying from a small to a moderate association (1–10%). The higher the ACWR, the lower the RRI risk. Conclusions: The ACWR showed an inversely proportional association with RRI risk that can be represented by a smooth L-shaped, second-order, polynomial decay curve. The ACWR using hours or kilometres yielded similar results. The coupled and uncoupled methods revealed similar associations with RRIs. The uncoupled method presented the best discrimination for ACWR strata. The EWMA method yielded sparse and non-significant results. [ABSTRACT FROM AUTHOR]

Context: Field hockey is popular worldwide; however, it entails a risk of injury. Injuries hamper players' participation in the sport and impose a burden on public health. Objective: To investigate the effectiveness of a structured exercise program among youth field hockey players on the injury rate, severity, and burden. Design: Quasi-experimental study. Setting: On field during 1 season of field hockey (October 2016 through June 2017). Patients or Other Participants: A convenience sample of 22 teams (291 players): 10 teams (135 players, mean age = 11.5 years [95% confidence interval (CI) = 11.2, 11.7 years]) in the intervention group and 12 teams (156 players, mean age = 12.9 years [95% CI = 12.6, 13.2 years]) in the control group. Intervention(s): The Warming-up Hockey program, a sexand age-specific, structured, evidence-informed warm-up program consisting of a preparation phase (ie, agility and cardiovascular warm-up exercises), movement skills (ie, stability and flexibility exercises), and sport-specific skills (ie, speed and strength exercises in field hockey situations). Participants in the control group performed their usual warm-up routines. Main Outcome Measure(s): Injury rate (ie, the number of injuries per 1000 player-hours of field hockey exposure), severity (ie, days of player time-loss), and burden on athletes' availability to play (ie, days of time loss due to injury per 1000 player-hours of field hockey exposure). Results: The injury rate was lower in the intervention group (hazard ratio of 0.64 [95% CI=0.38, 1.07]); however, this result was not statistically significant. The severity of injuries was similar in both groups (t statistic P = .73). The burden of injuries on players' field hockey participation was lower in the intervention group (difference of 8.42 [95% CI = 4.37, 12.47] days lost per 1000 player-hours of field hockey). Conclusions: Exposure to the Warming-up Hockey program was not significantly associated with a lower injury rate. No reduction was observed in the severity of injuries alone; however, the burden of injuries on players' field hockey participation was lower in the intervention group. [ABSTRACT FROM AUTHOR]

Researches have been performed to investigate the effects of phototherapy on improving performance and reduction of muscular fatigue. However, a great variability in the light parameters and protocols of the trials are a concern to establish the efficacy of this therapy to be used in sports or clinic. The aim of this study is to investigate the effectiveness, moment of application of phototherapy within an exercise protocol, and which are the parameters optimally effective for the improvement of muscular performance and the reduction of muscular fatigue in healthy people. Systematic searches of PubMed, PEDro, Cochrane Library, EMBASE, and Web of Science databases were conducted for randomized clinical trials to March 2017. Analyses of risk of bias and quality of evidence of the included trials were performed, and authors were contacted to obtain any missing or unclear information. We included 39 trials (861 participants). Data were reported descriptively through tables, and 28 trials were included in meta-analysis comparing outcomes to placebo. Meta-analysis was performed for the variables: time until reach exhaustion, number of repetitions, isometric peak torque, and blood lactate levels showing a very low to moderate quality of evidence and some effect in favor to phototherapy. Further investigation is required due the lack of methodological quality, small sample size, great variability of exercise protocols, and phototherapy parameters. In general, positive results were found using both low-level laser therapy and light-emitting diode therapy or combination of both in a wavelength range from 655 to 950 nm. Most of positive results were observed with an energy dose range from 20 to 60 J for small muscular groups and 60 to 300 J for large muscular groups and maximal power output of 200 mW per diode. [ABSTRACT FROM AUTHOR]