Eke Chika U, Cain Stephen M, Stirling Leia A
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Mechanical Engineering, The University of Michigan, 2350 Hayward, Ann Arbor, MI 48109, USA.
J Biomech. 2017 Nov 7;64:219-225. doi: 10.1016/j.jbiomech.2017.09.030. Epub 2017 Oct 7.
Agility performance is often evaluated using time-based metrics, which provide little information about which factors aid or limit success. The objective of this study was to better understand agility strategy by identifying biomechanical metrics that were sensitive to performance speed, which were calculated with data from an array of body-worn inertial sensors. Five metrics were defined (normalized number of foot contacts, stride length variance, arm swing variance, mean normalized stride frequency, and number of body rotations) that corresponded to agility terms defined by experts working in athletic, clinical, and military environments. Eighteen participants donned 13 sensors to complete a reactive agility task, which involved navigating a set of cones in response to a vocal cue. Participants were grouped into fast, medium, and slow performance based on their completion time. Participants in the fast group had the smallest number of foot contacts (normalizing by height), highest stride length variance (normalizing by height), highest forearm angular velocity variance, and highest stride frequency (normalizing by height). The number of body rotations was not sensitive to speed and may have been determined by hand and foot dominance while completing the agility task. The results of this study have the potential to inform the development of a composite agility score constructed from the list of significant metrics. By quantifying the agility terms previously defined by expert evaluators through an agility score, this study can assist in strategy development for training and rehabilitation across athletic, clinical, and military domains.
敏捷性表现通常使用基于时间的指标进行评估，这些指标几乎没有提供关于哪些因素有助于或限制成功的信息。本研究的目的是通过识别对表现速度敏感的生物力学指标来更好地理解敏捷性策略，这些指标是根据一系列身体佩戴的惯性传感器的数据计算得出的。定义了五个指标（归一化的足部接触次数、步幅长度方差、手臂摆动方差、平均归一化步频和身体旋转次数），它们对应于在体育、临床和军事环境中工作的专家所定义的敏捷性术语。18名参与者佩戴13个传感器完成一项反应性敏捷任务，该任务包括根据语音提示在一组锥体间穿梭。参与者根据完成时间被分为快速、中等和慢速表现组。快速组的参与者足部接触次数最少（按身高归一化）、步幅长度方差最高（按身高归一化）、前臂角速度方差最高且步频最高（按身高归一化）。身体旋转次数对速度不敏感，可能是在完成敏捷任务时由手和脚的优势决定的。本研究结果有可能为根据重要指标列表构建综合敏捷性评分提供信息。通过通过敏捷性评分量化专家评估者先前定义的敏捷性术语，本研究可以协助体育、临床和军事领域的训练和康复策略制定。
