Carlson H, Thorstensson A, Nilsson J
Department of Physiology III, Karolinska Institutet, Stockholm, Sweden.
Acta Physiol Scand. 1988 Jul;133(3):343-53. doi: 10.1111/j.1748-1716.1988.tb08416.x.
The mechanisms of adaptation of the trunk to changed mechanical conditions were studied during locomotion in man. The myoelectrical (EMG) activity in lumbar back muscles and the movements of the trunk were recorded in nine healthy subjects during walking and running on a motor-driven treadmill. Two different types of voluntary modifications of the movement pattern were used: (1) The trunk was kept in an extreme forward or backward tilted position. In both these situations the basic EMG pattern with two periods of activity per stride cycle was maintained during walking, whereas a major shift relative to the stride cycle (25% of the stride cycle duration) occurred in running with the trunk tilted backwards. The synchrony of the back muscle activation at both sides increased when locomotion was performed with the trunk tilted forwards. The relative duration of the EMG bursts was similar to normal locomotion and corresponded to 15-26% of the stride cycle duration in walking and 23-37% in running. (2) In the other type of modification the subjects were instructed to exaggerate the angular trunk movements either in the sagittal or in the frontal plane. The basic EMG pattern and phase relationships remained in most cases unchanged. One exception was running with exaggerated lateral movements, in which only one period of back muscle activity per stride cycle was observed. The relative duration of the bursts was longer in trials with exaggerated trunk movements as compared to normal locomotion. In walking and running with the trunk tilted forwards or backwards the lumbar back muscles were not always involved as prime movers of the trunk. This was in contrast to the more dynamic situations, in which the back muscle activity appeared to be directly involved in braking and reversing the exaggerated trunk movements.
在人体运动过程中，对躯干适应变化的力学条件的机制进行了研究。在电动跑步机上行走和跑步时，记录了9名健康受试者腰椎背部肌肉的肌电（EMG）活动和躯干的运动。使用了两种不同类型的对运动模式的自主改变：（1）将躯干保持在极度前倾或后倾位置。在这两种情况下，行走时每个步幅周期有两个活动期的基本EMG模式得以维持，而当躯干向后倾斜跑步时，相对于步幅周期（步幅周期持续时间的25%）出现了重大偏移。当躯干向前倾斜进行运动时，两侧背部肌肉激活的同步性增加。EMG爆发的相对持续时间与正常运动相似，在行走时相当于步幅周期持续时间的15 - 26%，在跑步时为23 - 37%。（2）在另一种改变类型中，受试者被指示在矢状面或额状面夸大躯干的角向运动。在大多数情况下，基本EMG模式和相位关系保持不变。一个例外是夸张的侧向运动跑步，其中每个步幅周期仅观察到一个背部肌肉活动期。与正常运动相比，在躯干运动夸张的试验中，爆发的相对持续时间更长。在躯干向前或向后倾斜的行走和跑步中，腰椎背部肌肉并不总是作为躯干的主要推动者参与其中。这与更动态的情况形成对比，在更动态的情况下，背部肌肉活动似乎直接参与制动和逆转夸张的躯干运动。
