Fatigue-induced changes in hamstrings’ active muscle stiffness: effect of contraction type and implications for strain injuries

Pavlos E. Evangelidis*, Xiyao Shan, Shun Otsuka, Chi Yang, Takaki Yamagishi, Yasuo Kawakami

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Purpose: Hamstring strain injuries may occur due to differential fatigue and compromised mechanical properties among the hamstring muscles. We examined (1) the effect of fatigue on hamstrings active muscle stiffness, and (2) whether contraction type affects active muscle stiffness changes during a submaximal fatiguing task. Methods: Nine healthy males completed 99 submaximal knee flexions in isometric (ISO), concentric (CON), and eccentric (ECC) conditions. We measured the knee flexor maximal voluntary torque (MVT) (pre/post), shear wave velocity (SWV) during contraction and transverse relaxation times (T2) (pre/post) in biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM) muscles. Results: MVT decreased substantially after all conditions (− 18.4 to − 33.6%). The average relative torque sustained during the task was lower in CON than ISO and ECC, but absolute torque was similar. SWV interindividual responses were highly variable across muscles and contraction types. On average, BFlh SWV tended to increase in ISO (0.4 m/s, 4.5%, p = 0.064) but decreased in ECC condition (− 0.8 m/s, − 7.7%, p < 0.01). ST SWV decreased in CON (− 1.1 m/s, − 9.0%, p < 0.01), while it remained unchanged in ISO and ECC. SM SWV decreased in CON (− 0.8 m/s, − 8.1%, p < 0.01), but it was unaffected in ISO and variable in ECC. Conclusion: Fatigue has a differential effect on the mechanical properties of the constituent hamstring muscles, as measured with shear wave elastography, depending upon contraction type. We found preliminary evidence that BFlh is more fatigued than ST or SM during eccentric contractions, which may explain its susceptibility to strain injuries.

Original languageEnglish
Pages (from-to)833-846
Number of pages14
JournalEuropean Journal of Applied Physiology
Issue number4
Publication statusPublished - 2023 Apr


  • Eccentric contractions
  • Fatigue
  • Hamstrings
  • Muscle stiffness
  • Shear wave elastography
  • Strain injuries

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)


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