Men and women show different adaptations of quadriceps activity following fatiguing contractions: an explanation for the increased incidence of sports-related knee injuries in women?

Research output: Contribution to journalArticlepeer-review


  • Nosratollah Hedayatpour
  • Diyar Mohammed Sediq Rashid
  • Zahra Izanloo
  • Hadi Seylaneh
  • Deborah Falla

External organisations

  • Department of Physical Education and Sport Science, University of Bojnord, , Bojnord, Iran.
  • University of Sulaimani
  • Azad University of Mashhad


We investigated whether adaptations of quadriceps muscle activity to fatiguing exercise differs between sexes. Fifteen healthy men (age, mean ± SD; 22. ± 2.4 yr, body mass 70.5 ± 11.4 kg, height 1.72 ± 0.06 m) and 15 healthy women (age, mean ± SD; 21 ± 1.8 yr, body mass 60 ± 7.5 kg, height 1.62 ± 0.07 m), all right leg dominant, participated in the study. Participants performed a submaximal isometric knee extension contraction at 50% of the maximum voluntary contraction (MVC) sustained until task failure before and after a fatiguing exercise. Surface electromyography (EMG) was simultaneously recorded from nine regions distributed over the medial, middle and lateral locations of the quadriceps muscles in a longitudinal direction corresponding to the vastus medialis, rectus femoris (RF) and vastus lateralis muscle, respectively. A significant reduction in maximal force and time to task failure were observed after fatiguing exercise for both sexes (P < 0.001). However, women displayed greater myoelectric manifestations of fatigue specifically for the RF during the post-fatigue sustained contraction (P < 0.05). The RF is more susceptible to fatiguing exercise in women compared to men which may partly explain the higher risk of knee injuries among female athletes during competitive sports.

Bibliographic note

Copyright © 2021 Elsevier Ltd. All rights reserved.


Original languageEnglish
Article number102552
Number of pages6
JournalJournal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
Early online date23 Apr 2021
Publication statusPublished - Jun 2021


  • Fatigue, Quadriceps, Electromyography, Gender differences, nee injury