無論是跑步或下樓梯均有著地動作的出現，而簡單的著地動作需有人體骨骼結構支撐外，更有下肢肌肉工作的相互配合，才得以有穩定與流暢的著地過程。而著地過程區分為著地前、著地瞬間與著地後等三個階段，其下肢肌肉會分別執行肌肉預收縮、自我保護機制與牽張反射等肌肉工作特徵，說明下肢肌肉工作對於著地動作扮演重要角色。本研究目的從探討牽張縮短循環的肌肉工作特徵，剖析著地工作中各階段的肌肉工作特性，期望能增進運動科學研究人員對於下肢肌肉工作有更深層的思維。

Landing is the common landing movement during running, or stepping downstairs. The simple landing movement not only needs the supporting of the human skeletal structure, but also the mutual muscle actions of lower extremities, in order to produce the landing movement stably and smoothly. There are three phases during the landing that include pre-landing, initial contact, and descending. And the lower extremity muscle will carry out the characteristics of pre-stretch, self-protect, stretch reflex and so on. However, the lower extremities muscles play an important role during landing. The aim of this study is insight into the muscle actions during landing period through the literature reviews of the patterns of stretch-shortening-cycle. This study provides and traces the issues of jump landing for the muscle action of lower extremities.