ALTERED MUSCLE ACTIVITY DURING LOCOMOTION POST-STROKE

描述（由申请人提供）：中风幸存者生活质量的主要障碍是行走能力受损，恢复运动能力是一个重要目标。本研究的目的是确定中风后行走能力受损的机制。运动通常以腿部肌肉活动的临界时间模式为特征。然而，在卒中后偏瘫患者中，肌肉活动的时间异常，导致运动缓慢和不安全。运动肌肉定时异常的原因尚不清楚；然而，一种主流理论认为，肌肉时间异常是由于过度活跃的拉伸反射。另一种可能性是，运动肌肉的激活模式从根本上被重组了。本研究旨在确定伸展反射的升高和运动模式的重组对中风后肌肉时间异常的贡献。有或没有中风后偏瘫的受试者将参与研究。使用踏板任务，运动方向将被操纵，并将引起腿部肌肉的皮肤反射。在踩踏板时，测量肌肉活动和皮肤反射振幅。据推测，如果异常的运动肌肉时间是由拉伸反射升高引起的，那么在肌肉延长过程中，无论蹬踏方向如何，都会出现异常的肌肉活动。如果运动模式在中风后重组，将观察到与踩踏板的生物力学成分顺序相关的肌肉时间的方向依赖性变化，皮肤反射调节将被重组。

DESCRIPTION (provided by applicant): A major obstacle to quality of life for stroke survivors is impaired walking ability, and restoration of locomotion is an important goal. The objective of this research is to identify mechanisms contributing to impaired walking ability post-stroke. Locomotion is normally characterized by critically-timed patterns of muscle activity in the legs. However, in persons with post-stroke hemiparesis, muscle activity is abnormally timed, which contributes to slow and unsafe locomotion. The causes of abnormal locomotor muscle timing are poorly understood; however, a dominant theory is that abnormal muscle timing is due to hyperactive stretch reflexes. Another possibility is that locomotor muscle activation patterns are fundamentally reorganized. This study aims to identify the contributions of elevated stretch reflexes and reorganization of the locomotor pattern to abnormal muscle timing post-stroke. Subjects with and without post-stroke hemiparesis will participate. Using a pedaling task, the direction of locomotion will be manipulated, and cutaneous reflexes will be elicited in leg muscles. Muscle activity and cutaneous reflex amplitude will be quantified during pedaling. It is hypothesized that, if abnormal locomotor muscle timing arises from elevated stretch reflexes, abnormal muscle activity will be present during muscle lengthening, regardless of pedaling direction. If the locomotor pattern is reorganized post-stroke, direction-dependent changes in muscle timing that are related to the sequence of the biomechanical components of pedaling will be observed, and cutaneous reflex modulation will be reorganized.