Context: Concussions are consequence of sports participation. Recent reports indicate there is an increased risk of lower-extremity musculoskeletal injury when returning to sport after concussion suggesting that achieving “normal” balance may not fully indicate the athlete is ready for competition. The increased risk of injury may indicate the need to refine a screening tool for clearance. Objective: Assess the between-session reliability and the effects of adding a cognitive task to static and dynamic postural stability testing in a healthy population. Setting: Clinical laboratory. Participants: Twelve healthy subjects (6 women; age 22.3 [2.9] y, height 174.4 [7.5] cm, weight 70.1 [12.7] kg) participated in this study. Design: Subjects underwent static and dynamic postural stability testing with and without the addition of a cognitive task (Stroop test). Test battery was repeated 10 days later. Dynamic postural stability testing consisted of a forward jump over a hurdle with a 1-legged landing. A stability index was calculated. Static postural stability was also assessed with and without the cognitive task during single-leg balance. Variability of each ground reaction force component was averaged. Main Outcome Measures: Interclass correlation coefficients (ICC2,1) were computed to determine the reliability. Standard error of measure, mean standard error, mean detectable change, and 95% confidence interval were all calculated. Results: Mean differences between sessions were low, with the majority of variables having moderate to excellent reliability (static .583–.877, dynamic .581–.939). The addition of the dual task did not have any significant effect on reliability of the task; however, generally, the ICC values improved (eyes open .583–.770, dual task .741–.808). Conclusions: The addition of a cognitive load to postural stability assessments had moderate to excellent reliability in a healthy population. These results provide initial evidence on the feasibility of dual-task postural stability testing when examining risk of lower-extremity musculoskeletal injury following return to sport in a concussed population.
Caroline Westwood, Carolyn Killelea, Mallory Faherty and Timothy Sell
Natalie L. Myers, Guadalupe Mexicano and Kristin V. Aguilar
while trying to minimizing injury risk. Training workload can be measured a variety of different ways, assessing both external and internal workload parameters. Internal workload is an individual’s response to an external stimulus. 1 A common measure of internal workload is session rate of perceived
Mahsa Jafari, Vahid Zolaktaf and Gholamali Ghasemi
14 is the cutoff score. 6 Scores lower than the cutoff indicate an increased relative injury risk; nevertheless scores higher than the cutoff do not indicate immunity from the risk. This is substantiated by several studies. For example, US service members who scored ≤14 were reported to be at about
Brad W. Willis, Katie Hocker, Swithin Razu, Aaron D. Gray, Marjorie Skubic, Seth L. Sherman, Samantha Kurkowski and Trent M. Guess
reinjury and demonstrate increased rates of knee pain and prevalence of osteoarthritis. 1 – 4 Investigations into preventive screening techniques monitoring ACL injury risk factors aimed at mitigating female injury rates are warranted. 1 , 2 The use of 3-dimensional marker-based motion capture systems in
Christie Powell, Jody Jensen and Samantha Johnson
causes an increase in injury risk and potential long-term health consequences, including burnout, growth plate injuries, and osteoarthritis. 7 Following an injury, identifying functional performance deficits, defined by return-to-sport criteria, minimizes injury risk factors and provides athletes with
Chelsey Klimek, Christopher Ashbeck, Alexander J. Brook and Chris Durall
and identify associations between different demographics, gym utilization, and CrossFit injury. To examine PT, fitness, and injury rate and to identify injury risk factors in a light infantry brigade beginning a new PT program that incorporated elements of ECPs, including CrossFit training. To define
While historically adolescents were removed from their parents to prepare to become warriors, this process repeats itself in modern times but with the outcome being athletic performance. This review considers the process of developing athletes and managing load against the backdrop of differing approaches of conserving and maximizing the talent available. It acknowledges the typical training “dose” that adolescent athletes receive across a number of sports and the typical “response” when it is excessive or not managed appropriately. It also examines the best approaches to quantifying load and injury risk, acknowledging the relative strengths and weaknesses of subjective and objective approaches. Making evidence-based decisions is emphasized, while the appropriate monitoring techniques are determined by both the sporting context and individual situation. Ultimately a systematic approach to training-load monitoring is recommended for adolescent athletes to both maximize their athletic development and allow an opportunity for learning, reflection, and enhancement of performance knowledge of coaches and practitioners.
Sean Williams, Grant Trewartha, Matthew J. Cross, Simon P.T. Kemp and Keith A. Stokes
Numerous derivative measures can be calculated from the simple session rating of perceived exertion (sRPE), a tool for monitoring training loads (eg, acute:chronic workload and cumulative loads). The challenge from a practitioner’s perspective is to decide which measures to calculate and monitor in athletes for injury-prevention purposes. The aim of the current study was to outline a systematic process of data reduction and variable selection for such training-load measures.
Training loads were collected from 173 professional rugby union players during the 2013–14 English Premiership season, using the sRPE method, with injuries reported via an established surveillance system. Ten derivative measures of sRPE training load were identified from existing literature and subjected to principal-component analysis. A representative measure from each component was selected by identifying the variable that explained the largest amount of variance in injury risk from univariate generalized linear mixed-effects models.
Three principal components were extracted, explaining 57%, 24%, and 9% of the variance. The training-load measures that were highly loaded on component 1 represented measures of the cumulative load placed on players, component 2 was associated with measures of changes in load, and component 3 represented a measure of acute load. Four-week cumulative load, acute:chronic workload, and daily training load were selected as the representative measures for each component.
The process outlined in the current study enables practitioners to monitor the most parsimonious set of variables while still retaining the variation and distinct aspects of “load” in the data.
Tim J. Gabbett and Rod Whiteley
The authors have observed that in professional sporting organizations the staff responsible for physical preparation and medical care typically practice in relative isolation and display tension as regards their attitudes toward training-load prescription (much more and much less training, respectively). Recent evidence shows that relatively high chronic training loads, when they are appropriately reached, are associated with reduced injury risk and better performance. Understanding this link between performance and training loads removes this tension but requires a better understanding of the relationship between the acute:chronic workload ratio (ACWR) and its association with performance and injury. However, there remain many questions in the area of ACWR, and we are likely at an early stage of our understanding of these parameters and their interrelationships. This opinion paper explores these themes and makes recommendations for improving performance through better synergies in support-staff approaches. Furthermore, aspects of the ACWR that remain to be clarified—the role of shared decision making, risk:benefit estimation, and clearer accountability—are discussed.
Jessica R. Fairbairn and Kellie C. Huxel Bliven
Clinical Scenario: Until recently, injury epidemiology data on elite Paralympic athletes were limited. Current data suggest high rates of shoulder injury in wheelchair athletes. Differences in shoulder injury rates between sports have not been reported in this population. Clinical Question: Is the incidence of shoulder injury in elite wheelchair athletes different between sports? Summary of Key Findings: Shoulder injury rates are high in elite wheelchair athletes, particularly in sports such as field events and fencing that require a stable base (eg, trunk, core control) from which to perform. Wheelchair racing requires repetitive motions that contribute to shoulder injuries, but rates are lower than field sports and fencing. Wheelchair curling and sledge hockey have low shoulder injury risk. Clinical Bottom Line: Shoulder injury rates vary based on sport in elite wheelchair athletes. In addition to incorporating shoulder complex specific rehabilitation for overuse shoulder injuries, clinicians should focus on core and trunk stabilization in elite wheelchair athletes competing in sports, such as field events and fencing. Strength of Recommendation: Grade C evidence exists that reports shoulder injury rates among elite wheelchair athletes differ based on sport participation.