Ball Nick B, Scurr Joanna C
Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom.
J Strength Cond Res. 2009 Aug;23(5):1433-41. doi: 10.1519/JSC.0b013e3181a4e97f.
The purpose of this article is to compare the bilateral neuromuscular and force contribution during a plyometric bounce drop jump task and to assess the affects of nonsimultaneous foot placement. Sixteen male participants performed bounce drop jumps from a height of 0.4 m. Mean peak electromyography activity of the soleus, medial, and lateral gastrocnemius of both legs was recorded from each phase of the drop jump and normalized to a reference dynamic muscle action. Resultant ground reaction force, ground contact time, and duration of the drop jumps were recorded from each leg. Multivariate analysis of variance was used to compare bilateral electromyographic activity, resultant peak ground reaction force, and contact duration. Pearson's correlations (r) ascertained relationships between normalized electromyographic activity and contact time. Significant differences were shown between left and right triceps surae normalized electromyography during precontact and contact40ms (p < 0.01). No significant differences were present in the contactpost40ms phase (p > 0.01). Significant differences were found between normalized soleus electromyography and both gastrocnemii for both legs during precontact (p < 0.01). No significant differences were found for within-leg normalized electromyography for the contact40ms phases and contactpost40ms phase (p > 0.01). Weak relationships were found between normalized electromyographic activity and nonsimultaneous foot contact (r < 0.2). This study showed differences between left and right triceps surae in neuromuscular strategies engaged in the early stages of a drop jump task. Differences in contact time initiation were present; however, they are not significant enough to cause neuromuscular differences in the plantar flexor muscles.
本文的目的是比较在纵跳式单脚跳任务中双侧的神经肌肉和力量贡献，并评估非同时双脚着地的影响。16名男性参与者从0.4米的高度进行单脚跳。在单脚跳的每个阶段记录双腿比目鱼肌、内侧和外侧腓肠肌的平均峰值肌电图活动，并将其归一化为参考动态肌肉动作。记录每条腿的地面合力、地面接触时间和单脚跳的持续时间。采用多变量方差分析来比较双侧肌电图活动、地面合力峰值和接触持续时间。皮尔逊相关性（r）确定了归一化肌电图活动与接触时间之间的关系。在预接触和接触40毫秒期间，左右小腿三头肌归一化肌电图之间存在显著差异（p<0.01）。在接触后40毫秒阶段没有显著差异（p>0.01）。在预接触期间，双腿的比目鱼肌归一化肌电图与两侧腓肠肌之间存在显著差异（p<0.01）。在接触40毫秒阶段和接触后40毫秒阶段，同一条腿的归一化肌电图没有显著差异（p>0.01）。归一化肌电图活动与非同时双脚着地之间存在弱相关性（r<0.2）。这项研究表明，在单脚跳任务的早期阶段，左右小腿三头肌在神经肌肉策略上存在差异。接触时间起始存在差异；然而，它们不足以导致跖屈肌出现神经肌肉差异。
