Functional and structural adaptations in skeletal muscle of trained athletes

Stephen Alway, J. D. MacDougall, D. G. Sale, J. R. Sutton, A. J. McComas

Research output: Contribution to journalArticle

84 Citations (Scopus)

Abstract

Twitch contractile and ultrastructural characteristics of the human triceps surae were determined in six male strength-trained athletes, six endurance-trained athletes, six active controls, and seven sedentary controls of similar height and age. Twitch contraction time in the triceps surae complex was 20% longer in strength-trained and sedentary groups than in endurance-trained or active control groups. In the 15 subjects peak twitch torque and one-half relation time in the triceps surae were 22.6 ± 7.9 N · m and 91.1 ± 18.3 ms, respectively. Mean fiber area in the gastrocnemius was approximately 1.6-, 1.7-, and 2.5-fold greater in the active control, endurance-trained, and strength-trained groups, respectively, relative to the sedentary group. Despite these large differences in fiber areas, the fiber fractional volume of the sarcoplasmic reticulum-transverse tubule network averaged 3.38 ± 0.86% and 5.50 ± 0.94% in type I and type II fibers, respectively, in all subjects. The fractional fiber volume of cytoplasm and lipid were similar for all four groups. However, mitochondrial volume was ~ 30% lower in both fiber types of the strength-trained group relative to the other groups. This implies that with exercise-induced hypertrophy, the sarcoplasmic reticulum, cytoplasm, and lipid components increase proportionately with contractile protein, whereas the mitochondrial fraction does not. The proportion of type I fibers in the soleus, medial gastrocnemius, and lateral gastrocnemius was 75.2 ± 8.3, 58.5 ± 6.1, and 52.4 ± 4.2%, respectively, and was similar in all subject groups. The results demonstrate that twitch duration is prolonged in strength-trained athletes relative to endurance athletes. Twitch contraction time may adapt independently of changes in the fractional volume of sarcoplasmic reticulum in type I or type II fibers.

Original languageEnglish (US)
Pages (from-to)1114-1120
Number of pages7
JournalJournal of Applied Physiology
Volume64
Issue number3
StatePublished - Jan 1 1988
Externally publishedYes

Fingerprint

Athletes
Skeletal Muscle
Sarcoplasmic Reticulum
Cytoplasm
Mitochondrial Size
Lipids
Contractile Proteins
Torque
Hypertrophy
Exercise
Control Groups

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Alway, S., MacDougall, J. D., Sale, D. G., Sutton, J. R., & McComas, A. J. (1988). Functional and structural adaptations in skeletal muscle of trained athletes. Journal of Applied Physiology, 64(3), 1114-1120.

Functional and structural adaptations in skeletal muscle of trained athletes. / Alway, Stephen; MacDougall, J. D.; Sale, D. G.; Sutton, J. R.; McComas, A. J.

In: Journal of Applied Physiology, Vol. 64, No. 3, 01.01.1988, p. 1114-1120.

Research output: Contribution to journalArticle

Alway, S, MacDougall, JD, Sale, DG, Sutton, JR & McComas, AJ 1988, 'Functional and structural adaptations in skeletal muscle of trained athletes', Journal of Applied Physiology, vol. 64, no. 3, pp. 1114-1120.
Alway S, MacDougall JD, Sale DG, Sutton JR, McComas AJ. Functional and structural adaptations in skeletal muscle of trained athletes. Journal of Applied Physiology. 1988 Jan 1;64(3):1114-1120.
Alway, Stephen ; MacDougall, J. D. ; Sale, D. G. ; Sutton, J. R. ; McComas, A. J. / Functional and structural adaptations in skeletal muscle of trained athletes. In: Journal of Applied Physiology. 1988 ; Vol. 64, No. 3. pp. 1114-1120.
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