Research

Hormonal

A higher percentage of type I skeletal muscle fibers is positively correlated with insulin-stimulated in vitro glucose transport rates in humans, whereas a lower percentage of type I fibers (associated with higher adiposity) correlates with reduced glucose transport.

Your muscle fiber composition influences how efficiently your muscles respond to insulin. A higher proportion of slow-twitch (Type I) fibers is associated with better glucose disposal. While you cannot easily change your genetic fiber type distribution, maintaining lower body fat and engaging in aerobic exercise may help optimize the metabolic function of your existing muscle fibers.

GoodSupportsHIGH confidence
type I fiber percentage correlated with the increment in glucose transport over basal (r = 0.50, P < 0.01) but not with absolute rate. When these subjects were excluded, type I fiber percentage correlated with both the absolute transport rate (r = 0.57, P < 0.01, Fig. 4) and the increment over basal in response to insulin (r = 0.50, P < 0.01).
Matthew S. Hickey et al. · American Journal of Physiology-Endocrinology and Metabolism · 1995

Why this rating

Direct human tissue measurement with rigorous statistical controls, though observational/correlational rather than interventional.

Source

Skeletal muscle fiber composition is related to adiposity and in vitro glucose transport rate in humans

Matthew S. Hickey et al. · American Journal of Physiology-Endocrinology and Metabolism · 1995

DOI 10.1152/ajpendo.1995.268.3.e453

cross_sectional · n=34Cited 302×
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DOI resolved against Crossref · corpus check 2026-06-10

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