Muscle Fiber Splitting Is a Physiological Response to Extreme Loading in Animals

Exerc Sport Sci Rev. 2019 Apr;47(2):108-115. doi: 10.1249/JES.0000000000000181.


Skeletal muscle fiber branching and splitting typically is associated with damage and regeneration and is considered pathological when observed during loading-induced hypertrophy. We hypothesize that fiber splitting is a nonpathological component of extreme loading and hypertrophy, which is primarily supported by evidence in animals, and propose that the mechanisms and consequences of fiber splitting deserve further exploration.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • Humans
  • Models, Animal
  • Muscle Fibers, Skeletal / pathology*
  • Muscle Fibers, Skeletal / physiology*
  • Muscle, Skeletal / growth & development*
  • Resistance Training
  • Stress, Physiological*