Svantesson U, Sunnerhagen K S
Department of Rehabilitation Medicine, Göteborg University, Sahlgrenska University Hospital, Sweden.
Eur J Appl Physiol Occup Physiol. 1997;75(4):312-8. doi: 10.1007/s004210050166.
The stretch-shortening cycle (SSC) is a natural muscle function where a concentric action is preceded by an eccentric action, and this leads to a higher concentric torque value in healthy persons. This study aimed to investigate the concentric torque output with and without preceding eccentric or isometric actions in patients with upper motor neuron lesions due to cerebro-vascular disease. Strength measurements of the plantar flexions were made in a dynamometer at different angular velocities (120 degrees.s-1 and 240 degrees.s-1) and recordings of electromyogram (EMG) were made simultaneously. The assessment was based on comparisons of the concentric torque values with and without preceding actions. The study showed a significantly higher percentage increase in concentric torque values after preceding actions in the affected leg compared with the nonaffected leg except at 120 degrees.s-1 with preceding isometric action. Relative EMG changes showed no differences between the legs except at 120 degrees.s-1 with preceding isometric action. We would suggest that the higher performance of the affected leg was caused by better utilization of elastic energy due to muscle stiffness which, despite reduced muscle strength, may have returned the patient's functional ability towards normal.
拉长-缩短循环（SSC）是一种自然的肌肉功能，即向心动作之前先有离心动作，这会使健康人的向心扭矩值更高。本研究旨在调查脑血管疾病所致上运动神经元损伤患者在有或无前驱离心或等长动作时的向心扭矩输出情况。在测力计上于不同角速度（120度·秒⁻¹和240度·秒⁻¹）下进行跖屈力量测量，并同时记录肌电图（EMG）。评估基于有或无前驱动作时向心扭矩值的比较。研究表明，除了在120度·秒⁻¹且有前驱等长动作时，患侧腿在前驱动作后的向心扭矩值百分比增加显著高于健侧腿。相对肌电图变化显示，除了在120度·秒⁻¹且有前驱等长动作时，两腿之间无差异。我们认为，患侧腿表现更好是由于肌肉僵硬导致弹性能量得到更好利用，尽管肌肉力量有所下降，但这可能使患者的功能能力恢复到接近正常水平。
