Specific tension of elbow flexor and extensor muscles based on magnetic resonance imaging

Yasuo Kawakami*, Kimitaka Nakazawa, Toshiro Fujimoto, Daichi Nozaki, Mitsumasa Miyashita, Tetsuo Fukunaga

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

114 Citations (Scopus)


Series cross-section images of the upper extremity were obtained for four men by magnetic resonance imaging (MRI) and anatomical cross-sectional areas (ACSA) of elbow flexor muscles [biceps brachii (BIC), brachialis (BRA), brachioradialis (BRD)] and extensor muscles [triceps brachii (TRI)] were measured. Physiological cross-sectional area (PCSA) was calculated from the muscle volume and muscle fibre length, the former from the series ACSA and the latter from the muscle length multiplied by previously reported fibre/muscle length ratios. Elbow flexion/extension torque was measured using an isokinetic dynamometer and the force at the tendons was calculated from the torque and moment arms of muscles measured by MRI. Maximal ACSA of TRI was comparable to that of total flexors, while PCSA of TRI was greater by 1.9 times. Within flexors, BRA had the greatest contribution to torque (47%), followed by BIC (34%) and BRD (19%). Specific tension related to the estimated velocity of muscle fibres were similar for elbow flexors and extensors, suggesting that the capacity of tension development is analogous between two muscle groups.

Original languageEnglish
Pages (from-to)139-147
Number of pages9
JournalEuropean Journal of Applied Physiology and Occupational Physiology
Issue number2
Publication statusPublished - 1994 Feb 1
Externally publishedYes


  • Moment arm
  • Muscle volume
  • Physiological cross-sectional area
  • Torque

ASJC Scopus subject areas

  • Physiology
  • Public Health, Environmental and Occupational Health


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