Muscle activity patterns altered during pedaling at different body orientations
Muscle activity patterns altered during pedaling at different body orientations
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DOI：
10.1016/0021-9290(96)00038-3
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发表时间：
1996-10-01
影响因子：
2.4
通讯作者：
Dairaghi, CA
中科院分区：
文献类型：
--
作者：
Brown, DA;Kautz, SA;Dairaghi, CA
重力是一种贡献力，被认为会强烈影响肢体运动的控制，因为它影响感觉输入，也有助于任务机制。通过改变重力对控制不同身体方向踩踏的总力的相对贡献，我们测试了这样的假设：关节扭矩和肌肉激活模式将被修改，以在改变的身体方向下产生稳态踩踏。 11 名健康受试者以不同的身体方向（从水平到垂直）踩改良测力计，保持相同的工作负荷 (80 J)、踏频 (60 rpm) 以及髋部和膝部运动学。测量踏板反作用力以及曲柄和踏板运动学，并用于计算关节扭矩和角度。记录四块肌肉（胫骨前肌、小腿三头肌、股直肌、股二头肌）的肌电图。肌肉激活的测量（关节扭矩和肌电图活动）显示出对身体方向的强烈依赖性，表明肌肉活动不是固定的，而是根据身体方向的改变而改变。模拟证实，虽然在不同的身体方向踩踏时不需要关节扭矩变化，但观察到的变化对于保持一致的曲柄角速度曲线是必要的。肌肉活动对身体方向的依赖性可能是由于感觉信息与包括终点特征的内部模型的神经整合，以产生一致的踩踏轨迹。因此，重力的感官结果和机械方面都是诸如踩踏板之类的运动任务的重要决定因素。由爱思唯尔科学有限公司出版
Gravity is a contributing force that is believed to influence strongly the control of limb movements since it affects sensory input and also contributes to task mechanics. By altering the relative contribution of gravitational force to the overall forces used to control pedaling at different body orientations, we tested the hypothesis that joint torque and muscle activation patterns would be modified to generate steady-state pedaling at altered body orientations. Eleven healthy subjects pedaled a modified ergometer at different body orientations (From horizontal to vertical), maintaining the same workload (80 J), cadence (60 rpm), and hip and knee kinematics. Pedal reaction forces and crank and pedal kinematics were measured and used to calculate joint torques and angles. EMG was recorded from four muscles (tibialis anterior, triceps surae, rectus femoris, biceps femoris). Measures of muscle activation (joint torque and EMG activity) showed strong dependence on body orientation, indicating that muscle activity is not fixed and is modified in response to altered body orientation. Simulations confirmed that, while joint torque changes were not necessary to pedal at different body orientations, observed changes were necessary to maintain consistent crank angular velocity profiles. Dependence of muscle activity on body orientation may be due to neural integration of sensory information with an internal model that includes characteristics of the endpoint, to produce consistent pedaling trajectories. Thus, both sensory consequences and mechanical aspects of gravitational forces are important determinants of locomotor tasks such as pedaling. Published by Elsevier Science Ltd.