Stiffness of individual quadriceps muscle assessed using ultrasound shear wave elastography during passive stretching

Jingfei Xu, François Hug, Siu Ngor Fu (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review

48 Citations (Scopus)


Muscle shear modulus (an index of muscle stiffness) measured using ultrasound shear wave elastography can be used to estimate changes in stiffness of an individual muscle. The aims of the present study were (1) to determine the shear modulus–knee angle relationship and the slack angle of the vastus medialis oblique (VMO), rectus femoris (RF), and vastus lateralis (VL) muscles; (2) to determine whether this differs between the muscles. Methods: Nine male rowers took part in the study. The shear modulus of VMO, RF, and VL muscles was measured while the quadriceps was passively stretched at 3°/s. The relationship between the muscle shear modulus and knee angle was plotted as shear modulus–knee angle curve through which the slack angle of each muscle was determined. Results: The shear modulus of RF was higher than that of VMO and VL when the muscles were stretched over 54° (all p < 0.01). No significant difference was found between the VMO and VL (all p > 0.05). The slack angle was similar among the muscles: 41.3° ± 10.6° 44.3° ± 9.1° and 44.3° ± 5.6° of knee flexion for VMO, RF, and VL, respectively (p = 0.626). Conclusion: This is the first study to experimentally determine the muscle mechanical behavior of individual heads of the quadriceps during passive stretching. Different pattern of passive tension was observed between mono- and bi-articular muscles. Further research is needed to determine whether changes in muscle stiffness are muscle-specific in pathological conditions or after interventions such as stretching protocols.
Original languageEnglish
Pages (from-to)245-249
Number of pages5
JournalJournal of Sport and Health Science
Issue number2
Publication statusPublished - Apr 2018


  • Muscle tension
  • Optimal length
  • Shear modulus
  • Slack angle
  • Stretch
  • Ultrasonography
  • Vastus lateralis
  • Vastus medialis

ASJC Scopus subject areas

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


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