Children's Exercise and Nutrition Center, McMaster University, Hamilton, Ontario, Canada.
J Electromyogr Kinesiol. 1997 Sep;7(3):179-86. doi: 10.1016/s1050-6411(97)84626-3.
This study attempted to assess and compare the amount of cocontraction present in thigh and leg muscles in three groups of children during treadmill walking and running. Thirty children, aged 7-8 (n = 10), 10-12 (n = 10) and 15-16 (n = 10) years, performed 4-min bouts of submaximal treadmill exercise at two walking and four running speeds, assigned in a randomized order. Three seconds of EMG data were collected during the final minute of each bout from the vastus lateralis (VL), hamstrings (H), tibialis anterior (TA) and soleus (S). The processed linear envelopes of VL and H, and likewise of TA and S, were overlapped and a cocontraction index calculated (area of overlap divided by the number of data points) for thigh and leg segments, respectively. Cocontraction was highest for the youngest children and lowest for the oldest, for both thigh and leg, whether expressed in terms of absolute speed or as a percentage of each child's VO(2 max). Larger amounts of cocontraction may help to explain the higher metabolic cost of locomotion for younger children, when compared with adolescents and adults.
本研究试图评估和比较三组儿童在跑步机上行走和跑步时大腿和小腿肌肉的共同收缩量。30 名 7-8 岁（n=10）、10-12 岁（n=10）和 15-16 岁（n=10）的儿童以随机顺序分配的两种步行速度和四种跑步速度进行了 4 分钟的亚最大强度跑步机运动。在每个回合的最后一分钟，从股外侧肌（VL）、腿筋（H）、胫骨前肌（TA）和比目鱼肌（S）采集 3 秒的 EMG 数据。VL 和 H 的处理后的线性包络线，以及 TA 和 S 的线性包络线，分别重叠，计算出大腿和小腿节段的共同收缩指数（重叠面积除以数据点数量）。对于大腿和小腿，无论以绝对速度还是以每个儿童最大摄氧量的百分比表示，年幼的儿童的共同收缩程度最高，而最年长的儿童的共同收缩程度最低。与青少年和成年人相比，对于年幼的儿童，较大程度的共同收缩可能有助于解释其更高的运动代谢成本。
