Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, McGill University, 3755 Côte Ste-Catherine Road, Montreal, QC, H3T 1E2, Canada.
Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1020 Pine Avenue West, Montreal, QC, H3A 1A2, Canada.
Sports Med. 2020 Jul;50(7):1243-1254. doi: 10.1007/s40279-020-01280-1.
Injuries occur when an athlete performs a greater amount of activity than what their body can withstand. To maximize the positive effects of training while avoiding injuries, athletes and coaches need to determine safe activity levels. The International Olympic Committee has recommended using the acute:chronic workload ratio (ACWR) to monitor injury risk and has provided thresholds to minimize risk when designing training programs. However, there are several limitations to the ACWR and how it has been analyzed which impact the validity of current recommendations and should discourage its use. This review aims to discuss previously published and novel challenges with the ACWR, and strategies to improve current analytical methods. In the first part of this review, we discuss challenges inherent to the ACWR. We explain why using a ratio to represent changes in activity may not always be appropriate. We also show that using exponentially weighted moving averages to calculate the ACWR results in an initial load problem, and discuss their inapplicability to sports where athletes taper their activity. In the second part, we discuss challenges with how the ACWR has been implemented. We cover problems with discretization, sparse data, bias in injured athletes, unmeasured and time-varying confounding, and application to subsequent injuries. In the third part, conditional on well-conceived study design, we discuss alternative causal-inference based analytical strategies that may avoid major flaws in studies on changes in activity and injury occurrence.
当运动员的活动量超过身体所能承受的量时，就会发生损伤。为了在避免受伤的同时最大限度地发挥训练的积极作用，运动员和教练需要确定安全的活动水平。国际奥林匹克委员会建议使用急性：慢性工作量比（ACWR）来监测受伤风险，并提供了在设计训练计划时降低风险的阈值。然而，ACWR 及其分析方法存在一些局限性，这些局限性影响了当前建议的有效性，应该劝阻其使用。本综述旨在讨论 ACWR 之前发表的和新出现的挑战，以及改进当前分析方法的策略。在本综述的第一部分，我们讨论了 ACWR 固有的挑战。我们解释了为什么使用比率来表示活动变化并不总是合适的。我们还表明，使用指数加权移动平均值来计算 ACWR 会导致初始负荷问题，并讨论了它们在运动员逐渐减少活动的运动中不适用。在第二部分，我们讨论了 ACWR 实施方面的挑战。我们涵盖了离散化、稀疏数据、受伤运动员的偏差、未测量和时变混杂以及对后续伤害的应用等问题。在第三部分，在考虑到精心设计的研究设计的前提下，我们讨论了基于因果推理的替代分析策略，这些策略可以避免关于活动变化和伤害发生的研究中的主要缺陷。
