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Effects of progressive resistance training on the contractile function of permeabilized single muscle fibers from the vastus lateralis muscle of older women
Author(s) -
Larkin Lisa M,
Figueroa Adriana,
AshtonMiller James A,
Horowitz Jeffrey F,
Alexander Neil B,
Cederna Paul S,
Claflin Dennis R,
Faulkner John A
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a382-d
Subject(s) - resistance training , vastus lateralis muscle , muscle fibre , muscle biopsy , medicine , fiber type , anatomy , fiber , biopsy , biology , chemistry , skeletal muscle , organic chemistry
The purpose of this study was to determine the effects of 12 weeks of progressive resistance training with shortening contractions on the function of permeabilized single muscle fibers obtained from biopsies of vastus lateralis (VLT) muscle of older women (n=16, 70–85 yrs). Ten fast (type IIa) and ten slow (type I) fibers were analyzed from each pre‐ and post‐training VLT biopsy. Each fiber was analyzed for cross‐sectional area (CSA), specific force (sF o ), and normalized power (nP max ). Following 12 weeks of training, the slow fibers from trained VLT did not differ in any of the parameters measured compared with fibers from pre‐trained VLT. In contrast, the fast fibers responded to the 12 week training protocol by having a 9% increase in mean sF o (P=0.001) and a 10% increase in mean nPmax (P=0.04). CSA of the fast fibers was unaffected by the training protocol. In conclusion, 12 weeks of progressive resistance training with shortening contractions improved the contractile function of the fast fibers obtained from the VLT muscles of old women. Supported by the Michigan Life Sciences Corridor.