TY - JOUR
T1 - Fatigue-induced decline in low-frequency common input to bilateral and unilateral plantar flexors during quiet standing
AU - Watanabe, Tatsunori
AU - Saito, Kotaro
AU - Ishida, Kazuto
AU - Tanabe, Shigeo
AU - Nojima, Ippei
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - Plantar flexor muscles play a crucial role in maintaining balance during quiet standing. The purpose of this study was to investigate the effect of their fatigue on common input to these muscles, using a coherence analysis. Thirteen healthy young male adults stood quietly before and after a fatigue protocol consisting of a heel raise exercise. Center of pressure (COP) displacement and electromyograms (EMGs) from the bilateral medial gastrocnemius and soleus muscles were recorded. EMG-EMG coherences between the bilateral homologous muscles (bilateral coherence) and within the unilateral muscles (unilateral coherence) in the right leg were calculated. Anteroposterior and mediolateral COP speeds, mediolateral COP SD, and 95% confidence ellipse area were larger in post- than pre-fatigue condition. Bilateral and unilateral coherences in delta band, that reflect comodulation of muscle activation, and bilateral coherence in alpha band, that is supposedly associated with the subcortical inputs, were smaller in post- than pre-fatigue condition. Unilateral coherences in alpha and beta band, reflecting physiological tremor and corticospinal drive, respectively, were not different between pre- and post-fatigue conditions. It is suggested that the low-frequency common input to the plantar flexor muscles is reduced following the fatiguing contraction during quiet standing, likely by a change in the postural control strategy.
AB - Plantar flexor muscles play a crucial role in maintaining balance during quiet standing. The purpose of this study was to investigate the effect of their fatigue on common input to these muscles, using a coherence analysis. Thirteen healthy young male adults stood quietly before and after a fatigue protocol consisting of a heel raise exercise. Center of pressure (COP) displacement and electromyograms (EMGs) from the bilateral medial gastrocnemius and soleus muscles were recorded. EMG-EMG coherences between the bilateral homologous muscles (bilateral coherence) and within the unilateral muscles (unilateral coherence) in the right leg were calculated. Anteroposterior and mediolateral COP speeds, mediolateral COP SD, and 95% confidence ellipse area were larger in post- than pre-fatigue condition. Bilateral and unilateral coherences in delta band, that reflect comodulation of muscle activation, and bilateral coherence in alpha band, that is supposedly associated with the subcortical inputs, were smaller in post- than pre-fatigue condition. Unilateral coherences in alpha and beta band, reflecting physiological tremor and corticospinal drive, respectively, were not different between pre- and post-fatigue conditions. It is suggested that the low-frequency common input to the plantar flexor muscles is reduced following the fatiguing contraction during quiet standing, likely by a change in the postural control strategy.
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U2 - 10.1016/j.neulet.2018.09.019
DO - 10.1016/j.neulet.2018.09.019
M3 - Article
C2 - 30218767
AN - SCOPUS:85053477872
SN - 0304-3940
VL - 686
SP - 193
EP - 197
JO - Neuroscience Letters
JF - Neuroscience Letters
ER -