Pincivero D M, Aldworth C, Dickerson T, Petry C, Shultz T
Department of Physical Therapy, Eastern Washington University, Cheney 99004, USA.
Eur J Appl Physiol. 2000 Apr;81(6):504-9. doi: 10.1007/s004210050075.
It has been hypothesized that the ability of the neuromuscular system to co-contract muscles for joint stabilization may be impaired during the development of fatigue. The purpose of this study was to examine muscle activation of the quadriceps and hamstring muscles during a prolonged closed kinetic chain exercise, the forward lunge. Eight males and two females [mean (SD) age 26.0 (2.3) years, height 177.2 (13.6) cm, body mass 82.8 (17.1) kg] with no prior knee pathology volunteered for this study. Subjects performed repeated forward lunges onto their dominant leg at the cadence of one full lunge cycle every 2 s, until the point of volitional failure. Digital switches were positioned to record foot-strike and knee-strike of the lunge leg at the midpoint of the lunge, as well as heel-strike upon return to stance. During the lunge performance, surface electromyographic (EMG) signals of the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and semitendinosus (ST) muscles of the supporting leg were measured. Heart rate was also monitored every 30 s during the performance. All EMG data were full-wave rectified, partitioned into up and down phases, and integrated over the entire exercise period. The results demonstrated a significant increase in activation of the VL, VM, and BF during performance of the forward lunge to volitional failure (P < 0.05). No significant increase was shown for the ST. Heart rate increased significantly over the course of the lunge. These findings suggest that activation of the VL, VM, and BF muscles occurs as a unit during performance of the forward lunge during both concentric and eccentric lunge phases.
有假说认为，在疲劳发展过程中，神经肌肉系统共同收缩肌肉以稳定关节的能力可能会受损。本研究的目的是在长时间的闭链运动（前弓步）中检查股四头肌和腘绳肌的肌肉激活情况。八名男性和两名女性[平均（标准差）年龄26.0（2.3）岁，身高177.2（13.6）厘米，体重82.8（17.1）千克]，既往无膝关节病变，自愿参加本研究。受试者以每2秒完成一个完整弓步周期的节奏，用优势腿重复进行前弓步，直到自愿力竭。在弓步的中点放置数字开关，以记录弓步腿的脚着地和膝盖着地情况，以及回到站立姿势时的脚跟着地情况。在进行弓步动作时，测量支撑腿的股外侧肌（VL）、股内侧肌（VM）、股二头肌（BF）和半腱肌（ST）的表面肌电图（EMG）信号。在动作过程中，还每30秒监测一次心率。所有EMG数据进行全波整流，分为上升和下降阶段，并在整个运动期间进行积分。结果表明，在前弓步至自愿力竭的过程中，VL、VM和BF的激活显著增加（P < 0.05）。ST没有显示出显著增加。在弓步过程中，心率显著增加。这些发现表明，在同心和偏心弓步阶段，VL、VM和BF肌肉在前弓步动作过程中作为一个整体被激活。
