Fatigue responses of human triceps surae muscles during repetitive maximal isometric contractions

Yasuo Kawakami*, Kenji Amemiya, Hiroaki Kanehisa, Shigeki Ikegawa, Tetsuo Fukunaga

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

76 Citations (Scopus)


Nine healthy men (22-45 yr) completed 100 repetitive maximal isometric contractions of the ankle plantar flexor muscles in two knee positions of full extension (K0) and flexion at 90°(K90), positions that varied the contribution of the gastrocnemii. Electromyographic activity was recorded from the medial and lateral gastrocnemii and soleus muscles by using surface electrodes. Plantar flexion torque in K0 was greater and decreased more rapidly than in K90. The electromyographic amplitude decreased over time, and there were no significant differences between muscles and knee joint positions. The level of voluntary effort, assessed by a supramaximal electrical stimulation during every 10th contraction, decreased from 96 to 70% (P < 0.05) with no difference between K0 and K90. It was suggested that a decrease in plantar flexion torque was attributable to both central and peripheral fatigue and that greater fatigability in K0 than in K90 would result from a greater contribution and hence more pronounced fatigue of the gastrocnemius muscle. Further support for this possibility was provided from changes in twitch torque.

Original languageEnglish
Pages (from-to)1969-1975
Number of pages7
JournalJournal of Applied Physiology
Issue number6
Publication statusPublished - 2000
Externally publishedYes


  • Central and peripheral fatigue
  • Electrical stimulation
  • Fiber types
  • Gastrocnemius and soleus muscles
  • Plantar flexion
  • Twitch interpolation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


Dive into the research topics of 'Fatigue responses of human triceps surae muscles during repetitive maximal isometric contractions'. Together they form a unique fingerprint.

Cite this