Department of Biology of Physical Activity, University of Jyväskylä, Neuromuscular Research Center, Finland.
J Electromyogr Kinesiol. 2013 Feb;23(1):118-24. doi: 10.1016/j.jelekin.2012.08.017. Epub 2012 Sep 26.
The purpose of this study was to examine single repetition characteristics and acute neuromuscular responses to typical hypertrophic (HL), maximal strength (MSL), and power (PL) loadings performed with two of the most common resistance modes; pneumatic and weight stack. Acute responses were assessed by measuring maximal voluntary contraction (MVC), corresponding quadriceps-EMG and resting and superimposed twitch torques. Activation level was calculated from the twitch torques. Decreases in MVC were greater during HL and MSL than during PL. During HL, resting twitch force decreased 8% (P < 0.05) more on the weight stack than on the pneumatic device. Furthermore, loading using the weight stack caused reduced resting twitch force, activation level, and EMG-amplitude after MSL and PL (P < 0.05-0.01). PL on the pneumatic device decreased MVC and rapid force production, while the respective PL on the weight stack device was specific to decreased rapid force production only. However, mean angular velocities and power of the repetitions were higher on the pneumatic device when using light loads. The present study showed that, at least in untrained subjects, the weight stack device induced greater levels of peripheral fatigue during HL. It also led to large central fatigue during MSL and PL. On the other hand, on the pneumatic device contraction velocity with low loads was higher compared to the weight stack device. Therefore, it is recommended that the resistance mode should be chosen according to the specific training goal.
本研究旨在探讨在两种最常见的阻力模式（气动和重量堆叠）下进行典型肥大（HL）、最大力量（MSL）和力量（PL）负荷时的单次重复特征和急性神经肌肉反应。急性反应通过测量最大自主收缩（MVC）、相应的股四头肌-EMG 以及静息和叠加的 twitch 扭矩来评估。激活水平是从 twitch 扭矩计算得出的。HL 和 MSL 期间 MVC 的下降大于 PL 期间。HL 时，与气动装置相比，在重量堆叠上，静息 twitch 力下降了 8%（P < 0.05）。此外，在 MSL 和 PL 后，使用重量堆叠进行加载会导致静息 twitch 力、激活水平和 EMG 幅度降低（P < 0.05-0.01）。气动装置上的 PL 降低了 MVC 和快速力量产生，而重量堆叠装置上的相应 PL 仅特异性地降低了快速力量产生。然而，当使用轻负荷时，气动装置上的重复平均角速度和功率更高。本研究表明，至少在未经训练的受试者中，HL 期间重量堆叠装置会引起更大程度的外周疲劳。它还导致 MSL 和 PL 期间的中枢疲劳较大。另一方面，与重量堆叠装置相比，气动装置在低负荷时的收缩速度更高。因此，建议根据特定的训练目标选择阻力模式。
