Effects of experimentally induced fatigue on healthy older adults’ gait: A systematic review

IntroductionWhile fatigue is ubiquitous in old age and visibly interferes with mobility, studies have not yet examined the effects of self-reported fatigue on healthy older adults’ gait. As a model that simulates this daily phenomenon, we systematically reviewed eleven studies that compared the effects of experimentally induced muscle and mental performance fatigability on gait kinematics, variability, kinetics, and muscle activity in healthy older adults.MethodsWe searched for studies in databases (PubMed and Web of Science) using Fatigue, Gait, and Clinical conditions as the main terms and extracted the data only from studies that experimentally induced fatigue by sustained muscle or mental activities in healthy older adults.ResultsEleven studies were included. After muscle performance fatigability, six of nine studies observed increases in stride length, width, gait velocity (Effect Size [ES] range: 0.30 to 1.22), inter-stride trunk acceleration variability (ES: 2.06), and ankle muscle coactivation during gait (ES: 0.59, n = 1 study). After sustained mental activity, the coefficient of variation of stride outcomes increased (ES: 0.59 to 0.67, n = 1 study) during dual-task but not single-task walking.ConclusionMuscle performance fatigability affects spatial and temporal features of gait and, mainly, inter-stride trunk acceleration variability. In contrast, sustained mental activity tends only to affect step variability during dual tasking. A critical and immediate step for future studies is to determine the effects of self-reported fatigue on gait biomechanics and variability in healthy older adults to verify the viability of experimentally induced fatigue as a model for the study of gait adaptability in old age.引言 尽管疲劳在老年群体中普遍存在，且会显著损害运动能力，但目前尚无研究探讨自我报告疲劳对健康老年人步态的影响。作为模拟这一日常现象的模型，我们系统综述了11项研究，这些研究对比了实验诱导的肌肉与精神运动疲劳对健康老年人步态运动学（kinematics）、变异性（variability）、步态动力学（kinetics）及肌肉活动的影响。方法 我们以“疲劳”“步态”与“临床病症”为主要检索词，在PubMed和Web of Science数据库中检索相关研究，并仅提取那些通过持续肌肉或精神活动对健康老年人实施实验性疲劳诱导的研究中的数据。结果 共纳入11项研究。在肌肉运动疲劳诱导后，9项研究中的6项观察到步长、步宽、步态速度（效应量，以下简称ES，范围：0.30~1.22）、步间躯干加速度变异性（ES：2.06）以及步态期间踝部肌肉共激活水平（ES：0.59，n=1项研究）出现升高。在持续精神活动诱导后，仅在双任务（dual-task）步行（而非单任务（single-task）步行）状态下，步幅相关指标的变异系数出现升高（ES：0.59~0.67，n=1项研究）。结论 肌肉运动疲劳会影响步态的时空特征，且主要影响步间躯干加速度变异性。与之相反，持续精神活动仅会在双任务状态下影响步幅变异性。未来研究亟需开展的一项关键且紧迫的工作，是明确自我报告疲劳对健康老年人步态生物力学（biomechanics）及变异性的影响，以验证实验诱导疲劳作为老年步态适应性（gait adaptability）研究模型的可行性。