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The Journal of Membrane Biology

, Volume 178, Issue 3, pp 175–183 | Cite as

The Specific Force of Single Intact Extensor Digitorum Longus and Soleus Mouse Muscle Fibers Declines with Aging

  • E.  González
  • M.L.  Messi
  • O.  Delbono

Abstract.

In the present study we measured, for the first time, the isometric specific force (SF, force normalized to cross sectional area) generated by single intact fibers from fast- (extensor digitorum longus, EDL) and slow-twitch (soleus) muscles from young adult (2–6), middle-aged (12–14) and old (20–24 month-old) mice. SF has also been measured in single intact flexor digitorum brevis fibers from young mice. Muscle fibers have been classified into fast- or slow-twitch based on the contraction kinetics. Maximum SF recorded in EDL and soleus fibers from young and middle-aged mice did not differ significantly. A significant age-dependent decline in maximum SF was recorded in EDL and soleus fibers from young or middle-aged to old mice. The SF was 377 ± 18, 417 ± 20 and 279 ± 18 kPa for EDL fibers from young, middle-aged and old mice, respectively and 397 ± 17, 405 ± 24 and 320 ± 33 kPa for soleus fibers from age-matched mice, respectively. The frequency needed to elicit maximum force in EDL and soleus fibers from middle-aged to old mice did not differ significantly. In conclusion, the specific force developed by both fast and slow-twitch single intact muscle fibers declines with aging and more significantly in the former.

Key words: Aging — Skeletal muscle — Single fiber —Soleus—Extensor digitorum longus—Flexor digitorum brevis— Excitation-contraction coupling — Sarcopenia 

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Copyright information

© Springer-Verlag New York Inc. 2000

Authors and Affiliations

  • E.  González
    • 1
  • M.L.  Messi
    • 1
  • O.  Delbono
    • 1
  1. 1.Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USAUS

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