Guess Trent M, Gray Aaron D, Willis Brad W, Guess Matthew M, Sherman Seth L, Chapman Dale W, Mann J Bryan
Department of Physical Therapy, University of Missouri, Columbia, MO 65211, USA.
Department of Orthopaedic Surgery, University of Missouri, Columbia, MO 65211, USA.
Sports (Basel). 2020 Dec 2;8(12):159. doi: 10.3390/sports8120159.
The purpose of this study was to relate the shape of countermovement jump (CMJ) vertical ground reaction force waveforms to discrete parameters and determine if waveform shape could enhance CMJ analysis. Vertical ground reaction forces during CMJs were collected for 394 male and female collegiate athletes competing at the National Collegiate Athletic Association (NCAA) Division 1 and National Association of Intercollegiate Athletics (NAIA) levels. Jump parameters were calculated for each athlete and principal component analysis (PCA) was performed on normalized force-time waveforms consisting of the eccentric braking and concentric phases. A -means clustering of PCA scores placed athletes into three groups based on their waveform shape. The overall average waveforms of all athletes in each cluster produced three distinct vertical ground reaction force waveform patterns. There were significant differences across clusters for all calculated jump parameters. Athletes with a rounded single hump shape jumped highest and quickest. Athletes with a plateau at the transition between the eccentric braking and concentric phase (amortization) followed by a peak in force near the end of the concentric phase had the lowest jump height and slowest jump time. Analysis of force-time waveform shape can identify differences in CMJ strategies in collegiate athletes.
本研究的目的是将反向运动跳跃（CMJ）垂直地面反作用力波形的形状与离散参数相关联，并确定波形形状是否能增强CMJ分析。收集了394名参加美国全国大学体育协会（NCAA）一级和全国大学体育协会（NAIA）级别的男女大学生运动员在CMJ过程中的垂直地面反作用力。计算了每名运动员的跳跃参数，并对由离心制动和向心阶段组成的归一化力-时间波形进行了主成分分析（PCA）。基于PCA得分的A均值聚类根据波形形状将运动员分为三组。每个聚类中所有运动员的总体平均波形产生了三种不同的垂直地面反作用力波形模式。所有计算出的跳跃参数在各聚类之间存在显著差异。具有圆形单峰形状的运动员跳得最高且最快。在离心制动和向心阶段（缓冲）之间的过渡处有一个平台，随后在向心阶段接近结束时力出现峰值的运动员，其跳跃高度最低，跳跃时间最慢。对力-时间波形形状的分析可以识别大学生运动员CMJ策略的差异。
