Exp Physiol. 2015 Sep 20. doi: 10.1113/EP085267. [Epub ahead of print]
Single muscle fibre contractile properties differ between bodybuilders, power athletes and controls.
We compared muscle fibre contractile properties of biopsies taken from m. vastus lateralis of 12 bodybuilders (BB; low- to moderate-intensity high-volume resistance training), 6 power athletes (PA; high-intensity low-volume combined with aerobic training) and 14 controls (C). Maximal isotonic contractions were performed in single muscle fibres, typed with SDS-PAGE. Fibre cross-sectional area (FCSA) was 67% and 88% (P<0.01) larger in BB than in PA and C, respectively, with no significant difference in FCSA between PA and C. Fibres of BB and PA developed a higher maximal isometric tension (32%, 50%, P < 0.01) than those of C. Specific tension (F0 ) of BB fibres was 62% and 41% lower than that of PA and C fibres (P < 0.05), respectively. Irrespective of fibre type, peak power (P) of PA fibres was 58% higher than that of BB fibres (P < 0.05), while BB fibres -despite considerable hypertrophy- had similar PP as C fibres. This work suggests that high-intensity low-volume resistance training with aerobic exercise improves PP, while low- to moderate-intensity high-volume resistance training does not affect PP and results in a reduction in F0 . We postulate that the decrease in specific tension is caused by differences in myofibrillar density and/or post-translational modifications of contractile proteins. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[PubMed – as supplied by publisher]