Assessment of human knee extensor muscles stress from in vivo physiological cross-sectional area and strength measurements

  • M. V. Narici
  • L. Landoni
  • A. E. Minetti
Article

DOI: 10.1007/BF00243511

Cite this article as:
Narici, M.V., Landoni, L. & Minetti, A.E. Europ. J. Appl. Physiol. (1992) 65: 438. doi:10.1007/BF00243511

Summary

The physiological cross-sectional areas (CSAp) of the vastus lateralis (VL), vastus intermedius (VI), vastus medialis (VM) and rectus femoris (RF) were obtained, in vivo, from the reconstructed muscle volumes, angles of pennation and distance between tendons of six healthy male volunteers by nuclear magnetic resonance imaging (MRI). In all subjects, the isometric maximum voluntary contraction strength (MVC) was measured at the optimum angle at which peak force occurred. The MVC developed at the ankle was 746.0 (SD 141.8) N and its tendon component (Ft) given by a mechanical advantage of 0.117 (SD 0.010), was 6.367 (SD 1.113) kN. To calculate the force acting along the fibres (Ff) of each muscle, Ft was divided by the cosine of the angle of pennation and multiplied for (CSAp · ΣCSAp−1), where ΣCSAp was the sum of CSAp of the four muscles. The resulting Ff values of VL, VI, VM and RF were: 1.452 (SD 0.531) kN, 1.997 (SD 0.187) kN, 1.914 (SD 0.827) kN, and 1.601 (SD 0.306) kN, respectively. The stress of each muscle was obtained by dividing these forces for the respective CSAp which was: 6.24 × 10−3 (SD 2.54 × 10−3) m2 for VL, 8.35 × 10−3 (SD 1.17 × 10−3) m2 for VI, 6.80 × 10−3 (SD 2.66 × 10−3) m2 for VM and 6.62 × 10−3 (SD 1.21 × 10−3) m2 for RE The mean value of stress of VL, VI, VM and RF was 250 (SD 19) kN m2; this value is in good agreement with data on animal muscle and those on human parallel-fibred muscle.

Key words

Force/CSA Muscle stress Specific tension Skeletal muscle strength MRI 

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • M. V. Narici
    • 1
  • L. Landoni
    • 2
  • A. E. Minetti
    • 1
  1. 1.Reparto Fisiologia Lavoro Muscolare, Istituto di Tecnologie Biomediche AvanzateConsiglio Nazionale delle RicercheMilanItaly
  2. 2.Centro S. Pio XServizio di Risonanza MagneticaMilanItaly