Type I muscle fibres

1. Endurance training increases type I muscle fibres in rats (almost 100% in the trained rats).

   “In adult animals the proportion of type I fibres was significantly higher in the MS of the trained than untrained animals.”

   Animalslife-long endurance trainingsoleus muscle

   Effects of ageing and physical training on rat skeletal muscle. An experimental study on the properties of collagen, laminin, and fibre types in muscles serving different functions

   Acta physiologica Scandinavica. Supplementum·1 Jan 1989

More on Endurance training

1. Type I muscle fibres are associated with mechanical efficiency in humans (r = 0.82).

   “revealing strong correlations between ηnet and the proportion of type I muscle fibres (r = 0.82)”

   Humansskeletal muscle

   Physiological determinants of mechanical efficiency during advanced ageing and disuse

   The Journal of physiology·2 Jan 2024