Sports Center, University of Malaya, Malaysia.
J Hum Kinet. 2011 Dec;30:5-12. doi: 10.2478/v10078-011-0067-0. Epub 2011 Dec 25.
This study was designed to quantify and compare Electromyographic activity (EMG) and applied load in quadriceps muscle within performing high intensity knee extension exercises by Elastic Resistance (ER) and Nautilus Machine (NM). Sixteen male and female subjects (22.4 ± 4.7 yrs) completed 8 RM seated knee extension by NM, elastic tubing with original length (E0) and elastic tubing with 30% decrement of original length (E30). The mean value of EMG and external force were calculated and synchronized across various segments of motion for the three modes of training. The results demonstrated that in the early concentric and late eccentric segments of contraction, NM elicited significantly higher muscle activation than both E30 and E0 (p < 0.05). However, in the mid-concentric and mid-eccentric as well as late concentric and early eccentric segments no significant differences were observed between NM and E30. These findings supported the approach that developing external recoil of force in ER device by reducing 30% of initial length of elastic material can offer similar neuromuscular activation compared with NM. On this basis, E30 can be suggested as an affordable and non-gym based exercise device which has the capacity to provide an appropriate high resistance stimulus to meet the training requirement of athletes.
本研究旨在定量比较弹性阻力（ER）和 Nautilus 器械（NM）在高强度膝关节伸展运动中股四头肌的肌电图（EMG）活动和应用负荷。16 名男性和女性受试者（22.4±4.7 岁）完成了 NM、原始长度弹性管（E0）和原始长度 30%缩短的弹性管（E30）的 8RM 坐姿膝关节伸展运动。对三种训练模式的各个运动阶段的 EMG 和外力的平均值进行了计算和同步。结果表明，在收缩的早期向心和晚期离心阶段，NM 引起的肌肉激活明显高于 E30 和 E0（p<0.05）。然而，在中向心和中离心以及晚期向心和早期离心阶段，NM 和 E30 之间没有观察到显著差异。这些发现支持了通过减少弹性材料初始长度的 30%在 ER 装置中产生外部回弹的方法，与 NM 相比可以提供类似的神经肌肉激活。在此基础上，可以推荐 E30 作为一种经济实惠且非健身房的运动设备，它有能力提供适当的高阻力刺激，以满足运动员的训练要求。
