Muscle volume is a major determinant of joint torque in humans

T. Fukunaga, M. Miyatani, M. Tachi, M. Kouzaki, Y. Kawakami, H. Kanehisa

Research output: Contribution to journalArticle

283 Citations (Scopus)

Abstract

Muscle force (MF) is linearly related to physiological cross-sectional area (CSA), which is obtained from muscle volume (MV) divided by fibre length. Taking into account the fact that joint torque (TQ) is determined by MF multiplied by the moment arm, the maximal TQ would be a function of MV. This proposition was tested in the present study by investigating the relationship between MV and TQ for elbow flexor (EF) and extensor (EE) muscles of 26 males. The MVs of EF and EE were determined from a series of muscle CSA by magnetic resonance imaging (MRI), and pennation angle (θ) and FL by ultrasonography (US). Maximal isometric TQ was measured at right angle of elbow joint for EF and EE. There was a highly signi(r)cant correlation between MV and TQ both for EF and EE (r = 0.95 and 0.96 respectively) compared with that between muscle CSA and TQ, suggesting the dependence of TQ on MV. Furthermore, prediction equations for MV (MVULT) from muscle thickness (MT) measured by US was developed with reference to MVMRI by the MRI on 26 subjects, and the equations were applied to estimate MV of healthy university students (CON; 160 males) and sports athletes (ATH; 99 males). There were signi(r)cant linear relationships between MVULT and TQ both for EF (r = 0.783) and EE (r = 0.695) for all subjects (n = 259). The MVULT was signi(r)cantly higher in ATH (by 32% for EF and 33% for EE, respectively) than in CON. Similarly, significantly greater TQ was observed in ATH (by 35% for EF, 37% for EE, respectively). The θ for EE showed no difference between both groups (17.8° for CON and 17.5° for ATH). On the other hand, the TQ to MV ratio were identical for CON and ATH. The results reveal that the muscle volume of the upper arm is a major determinant of joint torque (TQ), regardless of athletic training.

Original languageEnglish
Pages (from-to)249-255
Number of pages7
JournalActa Physiologica Scandinavica
Volume172
Issue number4
DOIs
Publication statusPublished - 2001 Sep 26

Keywords

  • Joint torque
  • Muscle volume
  • Specific tension
  • Ultrasound

ASJC Scopus subject areas

  • Physiology

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