Unintended activity in homologous muscle during intended unilateral contractions increases with greater task difficulty

Hironori Watanabe, Hiroaki Kanehisa, Yasuhide Yoshitake*

*この研究の対応する著者

研究成果: Article査読

4 被引用数 (Scopus)

抄録

Purpose: The present study aimed to examine (1) the effect of task difficulty on unintended muscle activation (UIMA) levels in contralateral homologous muscle, (2) the difference between young and old adults in degree of UIMA with respect to task difficulty, and (3) temporal correlations between intended and contralateral unintended muscle activity at low frequency during unilateral intended force-matching tasks. Methods: Twelve young (21.8 ± 2.4 years) and twelve old (69.9 ± 5.3 years) adult men performed steady isometric abductions with the left index finger at 20–80% of maximal voluntary contraction force. Two task difficulties were set by adjusting the spacing between two bars centered about the target force used for visual feedback on a monitor. The amplitude of surface electromyogram (aEMG) for both hands was calculated and normalized with respect to the maximal value. To determine if oscillations between intended and unintended muscle activities were correlated, cross-correlation function (CCF) of rectified EMG for both hands at low frequency was calculated for samples deemed adequate. Results: The unintended aEMG (right hand) had significant main effects in task difficulty, age, and target force (all P < 0.05) without any interactions. Distinct significant peaks in CCF (0.38 on average, P < 0.05) with small time lags were present between rectified EMGs of intended and unintended muscles in 14 of the 17 samples. Conclusions: The current results indicate that UIMA increases with greater task difficulty regardless of age, and temporal correlations exist between intended and contralateral unintended muscle activities at low frequency.

本文言語English
ページ(範囲)2009-2019
ページ数11
ジャーナルEuropean Journal of Applied Physiology
117
10
DOI
出版ステータスPublished - 2017 10月 1
外部発表はい

ASJC Scopus subject areas

  • 整形外科およびスポーツ医学
  • 公衆衛生学、環境および労働衛生
  • 生理学(医学)

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