In high-performance sport, science and medicine practitioners employ a variety of physical and psychological tests, training and match monitoring, and injury-screening tools for a variety of reasons, mainly to predict performance, identify talented individuals, and flag when an injury will occur. The ability to “predict” outcomes such as performance, talent, or injury is arguably sport science and medicine’s modern-day equivalent of the “Quest for the Holy Grail.” The purpose of this invited commentary is to highlight the common misinterpretation of studies investigating association to those actually analyzing prediction and to provide practitioners with simple recommendations to quickly distinguish between methods pertaining to association and those of prediction.
Alan McCall, Maurizio Fanchini, and Aaron J. Coutts
Patrick Ward, Aaron J. Coutts, Ricard Pruna, and Alan McCall
There is a common expression in sports that “there is no ‘I’ in team.” However, collectively, there is actually a very important “I” in sport teams—the individual athlete/player. Each player has his or her own unique characteristics including physical, physiological, and psychological traits. Due to these unique characteristics, each player requires individual provision—whether it be an injury risk profile and targeted prevention strategy or treatment/rehabilitation for injury, dietary regimen, recovery, or psychological intervention. The aim of this commentary is to highlight how 4 high-performance teams from various professional football codes are analyzing individual player data.
Annie C. Jeffries, Lee Wallace, Aaron J. Coutts, Shaun J. McLaren, Alan McCall, and Franco M. Impellizzeri
Background: Athlete-reported outcome measures (AROMs) are frequently used in research and practice but no studies have examined their psychometric properties. Objectives: Part 1—identify the most commonly used AROMs in sport for monitoring training responses; part 2—assess risk of bias, measurement properties, and level of evidence, based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines. Study Appraisal and Synthesis Methods: Methodological quality of the studies, quality of measurement properties, and level of evidence were determined using the COSMIN checklist and criteria. Results: Part 1—from 9446 articles screened for title and abstract, 310 out of 334 full texts were included; 53.9% of the AROMs contained multiple items, while 46.1% contained single items. Part 2—from 1895 articles screened for title and abstract, 71 were selected. Most measurement properties of multiple-item AROMs were adequate, but content validity and measurement error were inadequate. With the exclusion of 2 studies examining reliability and responsiveness, no validity studies were found for single items. Conclusions: The measurement properties of multiple-item AROMs derived from psychometrics were acceptable (with the exclusion of content validity and measurement error). The single-item AROMs most frequently used in sport science have not been validated. Additionally, nonvalidated modified versions of the originally nonvalidated items are common. Until proper validation studies are completed, all conclusions based on these AROMs are questionable. Established reference methods, such as those of clinimetrics, should be used to develop and assess the validity of AROMs.
Benoit Delaval, Abd-Elbasset Abaïdia, Barthélémy Delecroix, Franck Le Gall, Alan McCall, Said Ahmaidi, and Gregory Dupont
Purpose: To analyze the relationships between the recovery kinetics experienced by professional football players and noncontact injury. Methods: A cohort of 46 professional football players (age 24.2 [4.7] y) from the same team (French Ligue 1) was monitored each day between matches when the team played twice a week. The recovery monitoring procedure was implemented after 38 matches and included some questionnaires: duration of sleep, Hooper scale (quality of sleep, level of stress, fatigue, and muscle soreness), perceived recovery status scale, creatine kinase concentrations, a countermovement jump, and an isometric force test. Noncontact injuries were collected during these periods. Results: Noncontact injuries were associated with perceived fatigue and muscle soreness 2 days (relative risk [RR] = 1.89 and 1.48, respectively) and 3 days following the matches (RR = 2.08 and 2.08, respectively). An increase of sleep quantity during the 2 nights following a match was significantly associated with a lower RR (RR = 0.65), as well as a lower decrement score on the isometric force test on each of the 3 days after the matches (RR = 0.97, RR = 0.99, and RR = 0.97, respectively). No other association was reported for the variables sleep quality, stress, perceived recovery, creatine kinase concentrations, countermovement jump, and noncontact injuries. Conclusion: During a congested schedule, implementing a recovery monitoring protocol including questionnaires about fatigue, muscle soreness, quantity of sleep, and a physical test of isometric force could help practitioners prevent injuries.
Abd-Elbasset Abaïdia, Julien Lamblin, Barthélémy Delecroix, Cédric Leduc, Alan McCall, Mathieu Nédélec, Brian Dawson, Georges Baquet, and Grégory Dupont
To compare the effects of cold-water immersion (CWI) and whole-body cryotherapy (WBC) on recovery kinetics after exercise-induced muscle damage.
Ten physically active men performed single-leg hamstring eccentric exercise comprising 5 sets of 15 repetitions. Immediately postexercise, subjects were exposed in a randomized crossover design to CWI (10 min at 10°C) or WBC (3 min at –110°C) recovery. Creatine kinase concentrations, knee-flexor eccentric (60°/s) and posterior lower-limb isometric (60°) strength, single-leg and 2-leg countermovement jumps, muscle soreness, and perception of recovery were measured. The tests were performed before and immediately, 24, 48, and 72 h after exercise.
Results showed a very likely moderate effect in favor of CWI for single-leg (effect size [ES] = 0.63; 90% confidence interval [CI] = –0.13 to 1.38) and 2-leg countermovement jump (ES = 0.68; 90% CI = –0.08 to 1.43) 72 h after exercise. Soreness was moderately lower 48 h after exercise after CWI (ES = –0.68; 90% CI = –1.44 to 0.07). Perception of recovery was moderately enhanced 24 h after exercise for CWI (ES = –0.62; 90% CI = –1.38 to 0.13). Trivial and small effects of condition were found for the other outcomes.
CWI was more effective than WBC in accelerating recovery kinetics for countermovement-jump performance at 72 h postexercise. CWI also demonstrated lower soreness and higher perceived recovery levels across 24–48 h postexercise.
Adam Field, Liam D. Harper, Bryna C.R. Chrismas, Peter M. Fowler, Alan McCall, Darren J. Paul, Karim Chamari, and Lee Taylor
Purpose: To survey soccer practitioners’ recovery strategy: (1) use, (2) perceived effectiveness, and (3) factors influencing their implementation in professional soccer. Methods: A cross-sectional convenience sample of professional soccer club/confederation practitioners completed a web-based survey (April to July 2020). Pearson chi-square and Fisher exact tests with Cramer V (φ − c) assessed relationships and their strength, respectively, between the perceived effectiveness and frequency of strategy use. Results: A total of 80 soccer practitioners (13 countries) completed the survey. The 3 most important recovery objectives were “alleviating muscle damage/fatigue,” “minimizing injury risk,” and “performance optimization.” The most frequently used strategies were active recovery, structured recovery day, extra rest day, massage, cold-water therapy, and carbohydrate provision (predominantly on match day and match day + 1). Relationships were identified between perceived effectiveness and frequency of strategy use for sleep medication (P < .001, φ − c = 0.48), carbohydrate provision (P = .007, φ − c = 0.60), protein provision (P = .007, φ − c = 0.63), an extra rest day (P < .001, φ − c = 0.56), and a structured recovery day (P = .049, φ − c = 0.50). Conclusions: The study demonstrates that professional soccer practitioners have a range of objectives geared toward enhancing player recovery. A disconnect is apparent between the perceived effectiveness of many recovery strategies and their frequency of use in an applied setting. Novel data indicate that strategies are most frequently employed around match day. Challenges to strategy adoption are mainly competing disciplinary interests and resource limitations. Researchers and practitioners should liaise to ensure that the complexities involved with operating in an applied environment are elucidated and apposite study designs are adopted, in turn, facilitating the use of practically effective and compatible recovery modalities.