Kawashima Noritaka, Nakazawa Kimitaka, Akai Masami
Department of Rehabilitation for Movement Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.
Med Sci Sports Exerc. 2005 Jun;37(6):915-21. doi: 10.1249/01.mss.0000170488.86528.08.
Even in the paralyzed lower limb muscle, EMG activity can be induced by imposing passive leg movement in standing posture in persons with spinal cord injury (SCI). The purpose of the present study was to ascertain whether the oxygenation level of the paralyzed lower limb muscle covaried with the muscle EMG activity during imposed passive leg movement.
Six motor-complete SCI subjects and four neurologically normal controls were placed on a gait-training apparatus that enabled the SCI subjects to stand and move their legs passively. After a 1-min resting stage, consecutive passive alternate leg movements were performed at different frequencies (0.8, 1, 1.2, and 1 Hz, for 3 min at each stage). To obtain postexercise data, subjects were kept in a standing posture for 5 min after passive movement ceased. The EMG activity and concentration changes in the oxygenated (oxy-) and deoxygenated hemoglobin (Hb) (deoxy-Hb) were continuously measured using near-infrared spectroscopy (NIRS) from the gastrocnemius muscle.
In all SCI subjects, muscle EMG activity was observed during passive leg movement. The oxy-Hb level gradually increased, whereas the deoxy-Hb decreased, and these changes were independent of the total Hb changes. In the recovery stage, the total Hb level was found to exceed the preexercise level. In contrast to the SCI patients, the normal subjects showed neither EMG activity nor changes in oxy- or deoxy-Hb.
The present results demonstrate that passive leg movement can induce not only muscular activity but also alteration of muscle oxygenation level in the paralyzed lower leg. Particularly, induced muscular activity seems to correlate with increased perfusion of the muscle.
即使在脊髓损伤（SCI）患者的瘫痪下肢肌肉中，通过让患者在站立姿势下进行被动腿部运动也可诱发肌电图（EMG）活动。本研究的目的是确定在进行被动腿部运动时，瘫痪下肢肌肉的氧合水平是否与肌肉EMG活动协同变化。
六名运动完全性SCI受试者和四名神经功能正常的对照者被放置在一个步态训练设备上，该设备能使SCI受试者站立并被动移动其腿部。在1分钟的休息阶段后，以不同频率（0.8、1、1.2和1Hz，每个阶段持续3分钟）连续进行被动交替腿部运动。为了获得运动后的数据，在被动运动停止后让受试者保持站立姿势5分钟。使用近红外光谱（NIRS）连续测量腓肠肌的EMG活动以及氧合血红蛋白（oxy-Hb）和脱氧血红蛋白（Hb）（deoxy-Hb）的浓度变化。
在所有SCI受试者中，被动腿部运动期间均观察到肌肉EMG活动。氧合血红蛋白水平逐渐升高，而脱氧血红蛋白水平降低，且这些变化与总血红蛋白变化无关。在恢复阶段，发现总血红蛋白水平超过运动前水平。与SCI患者相反，正常受试者既未表现出EMG活动，也未出现氧合血红蛋白或脱氧血红蛋白的变化。
目前的结果表明，被动腿部运动不仅可以诱发瘫痪小腿的肌肉活动，还可以改变其肌肉氧合水平。特别是，诱发的肌肉活动似乎与肌肉灌注增加相关。
