Partyka & Waśkiewicz 2021, musculoskeletal consequences of ultramarathon

Narrative review in Frontiers in Physiology on what training and racing ultramarathons do to the musculoskeletal system. Eccentric contractions, far more frequent in mountain ultras because downhill running forces the active muscle to lengthen under load, are described as particularly damaging to muscle fibres; the quadriceps are among the most affected sites for post-race pain and damage. The review notes that appropriate training reduces creatine-kinase release and speeds recovery, and that endurance training selectively hypertrophies type I fibres. A descriptive synthesis, not a controlled trial; useful as a map of the stresses rather than a source of effect sizes.