Mileva Katya N, Morgan Julie, Bowtell Jo
Sport and Exercise Science Research Centre, London South Bank University, London, UK.
J Sports Sci. 2009 Apr;27(6):611-23. doi: 10.1080/02640410802707011.
The aim of this study was to differentiate between endurance and power athletes based on electromyographic (EMG) data analysed using new spectral indices. Nine endurance and six strength athletes were recruited to complete sets of knee extension repetitions (15 per set) until exhaustion, with each set followed by a maximal voluntary isometric knee extensor contraction. Peripheral muscle fatigue of the vastus lateralis, vastus medialis, and rectus femoris (bilaterally) was quantified by the changes in median frequency of the EMG power spectrum and a new spectral EMG fatigue index. Cluster analysis of the fatigue indices differentiated athletes into two groups: endurance (fatigue resistant) and strength (faster fatigue), whereas cluster analysis of the median EMG power spectrum frequency produced six indistinct groups. The average fatigue index for the quadriceps group increased across repetitions by 40 +/- 24% in the endurance group and by 184 +/- 12% in the strength group. The decrease in peak force and power across repetitions, and the rate of force decrease during maximal voluntary contraction per set, were significantly smaller for the endurance than for the strength group. The new spectral EMG indices effectively discriminated between strength and endurance athletes, thus providing a useful functional index that could be applied to track training adaptations as well as potentially talent identification.
本研究的目的是基于使用新的频谱指数分析的肌电图（EMG）数据，区分耐力运动员和力量运动员。招募了9名耐力运动员和6名力量运动员，让他们完成几组膝关节伸展重复动作（每组15次），直至力竭，每组动作后进行一次最大自主等长膝关节伸肌收缩。通过EMG功率谱的中位频率变化和一个新的频谱EMG疲劳指数，对股外侧肌、股内侧肌和股直肌（双侧）的外周肌肉疲劳进行量化。对疲劳指数进行聚类分析，将运动员分为两组：耐力型（抗疲劳）和力量型（疲劳更快），而对EMG功率谱频率中位数进行聚类分析则产生了六个不清晰的组。耐力组股四头肌组的平均疲劳指数在重复动作过程中增加了40±24%，力量组增加了184±12%。耐力组重复动作过程中峰值力和功率的下降，以及每组最大自主收缩过程中力的下降速率，均显著小于力量组。新的频谱EMG指数有效地区分了力量运动员和耐力运动员，从而提供了一个有用的功能指数，可用于跟踪训练适应性以及潜在的人才识别。
