期刊
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY
卷 112, 期 6, 页码 2323-2330出版社
SPRINGER
DOI: 10.1007/s00421-011-2205-8
关键词
Contractile properties; H-reflex; Neuromuscular fatigue; Middle-distance events; Plantar flexion
The aim of this study was to characterize the effect of a 5 km running time trial on the neuromuscular properties of the plantar flexors. Eleven well-trained triathletes performed a series of neuromuscular tests before and immediately after the run on a 200 m indoor track. Muscle activation (twitch interpolation) and normalized EMG activity were assessed during maximal voluntary contraction (MVC) of plantar flexors. Maximal H-reflexes and M-waves were evoked at rest (i.e. (MAX) and (MAX), respectively) and during MVC (i.e. (SUP) and (SUP), respectively). MVC significantly declined (-27%; < 0.001) after the run, due to decrease in muscle activation (-8%; < 0.05) and (MAX)-normalized EMG activity (-13%; < 0.05). Significant reductions in M-wave amplitudes ( (MAX): -13% and (SUP): -16%; < 0.05) as well as (MAX)/ (MAX) (-37%; < 0.01) and (SUP)/ (SUP) (-25%; < 0.05) ratios occurred with fatigue. Following exercise, the single twitch was characterized by lower peak torque (-16%; < 0.001) as well as shorter contraction (-19%; < 0.001) and half-relaxation (-24%; < 0.001) times. In conclusion, the reduction in plantar flexors strength induced by a 5 km running time trial is caused by peripheral adjustments, which are attributable to a failure of the neuromuscular transmission and excitation-contraction coupling. Fatigue also decreased the magnitude of efferent motor outflow from spinal motor neurons to the plantar flexors and part of this suboptimal neural drive is the result of an inhibition of motoneuron pool reflex excitability.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据