Architecture of contracting human muscles and its functional significance

Yasuo Kawakami, Yoshiho Ichinose, Keitaro Kubo, Masamitsu Ito, Morihiro Imai, Tetsuo Fukunaga

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

This paper reviews three of our recent studies on human muscle architecture in vivo. 1. Hypertrophic changes: From B-mode ultrasonograms, pennation angles and thickness of triceps brachii were determined for normal subjects and highly-trained bodybuilders. There was a significant correlation between muscle thickness and pennation angles. It was confirmed that hypertrophy was accompanied by an increase in pennation angles. 2. Variation of fascicle architecture: Fascicle lengths and pennation angles were obtained from different positions in the gastrocnemius muscle while the subjects relaxed and performed isometric plantar flexion. The fascicle length was uniform throughout the muscle and shortened by contraction (30-34% at 50% of the maximal force). On the other hand, pennation angles differed among positions and increased by contraction. The muscle thickness did not change by contraction. Pennation angles were significantly correlated with muscle thickness within muscle. 3. Joint position-fascicle length relationships: Ultrasonic images of the gastrocnemius and soleus muscles were obtained while the subject performed maximal isometric plantarflexion at various joint positions, from which fascicle lengths and angles were determined. The length-force relationship of each muscle was estimated. It was suggested that human muscle architecture has an ability to make substantial changes to adapt to environmental conditions.

Original languageEnglish
Pages (from-to)88-97
Number of pages10
JournalJournal of Applied Biomechanics
Volume16
Issue number1
Publication statusPublished - 2000 Feb
Externally publishedYes

Fingerprint

Muscles
Skeletal Muscle
Joints
Muscle Contraction
Ultrasonics
Hypertrophy

Keywords

  • Fascicle length
  • Length-force relationship
  • Pennation
  • Ultrasound

ASJC Scopus subject areas

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

Cite this

Kawakami, Y., Ichinose, Y., Kubo, K., Ito, M., Imai, M., & Fukunaga, T. (2000). Architecture of contracting human muscles and its functional significance. Journal of Applied Biomechanics, 16(1), 88-97.

Architecture of contracting human muscles and its functional significance. / Kawakami, Yasuo; Ichinose, Yoshiho; Kubo, Keitaro; Ito, Masamitsu; Imai, Morihiro; Fukunaga, Tetsuo.

In: Journal of Applied Biomechanics, Vol. 16, No. 1, 02.2000, p. 88-97.

Research output: Contribution to journalArticle

Kawakami, Y, Ichinose, Y, Kubo, K, Ito, M, Imai, M & Fukunaga, T 2000, 'Architecture of contracting human muscles and its functional significance', Journal of Applied Biomechanics, vol. 16, no. 1, pp. 88-97.
Kawakami, Yasuo ; Ichinose, Yoshiho ; Kubo, Keitaro ; Ito, Masamitsu ; Imai, Morihiro ; Fukunaga, Tetsuo. / Architecture of contracting human muscles and its functional significance. In: Journal of Applied Biomechanics. 2000 ; Vol. 16, No. 1. pp. 88-97.
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