Research
Mixed
High oxidative muscle fibers remain small despite high protein synthesis capacity because increased mitochondrial biogenesis via AMPK attenuates myofibrillar protein synthesis and higher expression of E3-ligases increases protein degradation.
High oxidative (Type I) fibers are genetically predisposed to be smaller and more fatigue-resistant. They have higher rates of protein turnover (both synthesis and degradation). To maximize size in these fibers, resistance training must overcome the natural tendency for degradation and the inhibitory effects of mitochondrial signaling.
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Competition between signaling pathways for synthesis of myofibrillar proteins and proteins associated with oxidative metabolism; i.e., increased mitochondrial biogenesis via AMP-activated protein kinase attenuates the rate of protein synthesis; relatively higher expression levels of E3-ligases and proteasome-mediated protein degradation in high oxidative fibers.
Why this rating
Review article summarizing molecular mechanisms.
Source
The muscle fiber type–fiber size paradox: hypertrophy or oxidative metabolism?
T. van Wessel et al. · European Journal of Applied Physiology · 2010
DOI 10.1007/s00421-010-1545-0
narrative_reviewCited 286×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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