Non-uniform distribution of passive muscle stiffness within hamstring

Naokazu Miyamoto*, Noriko Kimura, Kosuke Hirata

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Limited information is available on whether stiffness is different within and between the constituents of the hamstring, that is, the biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM). Therefore, understanding of hamstring injuries and stretching effect on hamstring stiffness is difficult. The present study primarily aimed to identify whether passive muscle stiffness differs between the BFlh, ST, and SM and between the proximal, middle, and distal sites within each muscle. Secondly, the effect of stretching exercise on the heterogeneity in passive muscle stiffness was examined. In the lengthened hamstring positions by extending the knee joint or flexing the hip joint, passive muscle shear modulus (a measure of stiffness) at the proximal, middle, and distal sites of the BFlh, ST, and SM was measured by using ultrasound shear wave elastography. Furthermore, before and after five repetitions of 90-seconds static stretching for the hamstring, passive muscle shear modulus at the proximal and distal sites of the SM was measured. The shear modulus was significantly higher in the SM than in the BFlh and ST and higher at the distal site than the proximal site in all muscles. After the stretching, the higher shear modulus at the distal site of the SM compared to the proximal site was still observed (pre-stretching: +80%, post-stretching: +81%). These findings indicate that passive muscle stiffness varies within the hamstring regardless of performing stretching exercise and that passive muscle stiffness is not highest at the proximal site of the SM where a stretching-type hamstring strain typically occurs.

Original languageEnglish
Pages (from-to)1729-1738
Number of pages10
JournalScandinavian Journal of Medicine and Science in Sports
Issue number9
Publication statusPublished - 2020 Sept 1
Externally publishedYes


  • elastography
  • hamstring strain injury
  • semimembranosus
  • shear modulus
  • stretching
  • ultrasound

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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