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Muscle Fiber Type I

Slow-Twitch Fibers

Anatomy

Short definition

Slow-twitch muscle fibres — endurance-oriented, oxidative.

Full definition

Type I (slow oxidative) fibres have high mitochondrial (MX) density and capillarization, low force and high endurance, recruited at low-to-moderate intensities and long duration, growing slowly.

Examples

Marathon running relies on Type I fibres.

Related terms

Muscle Fiber Type IIa Muscle Fiber Type IIx MX (Mitochondria) Endurance