Research

Hormonal

The reduced force production in the morning associated with satellite cells results in significantly less contractile injury (force loss and dystrophin-negative fibers) following eccentric exercise.

Eccentric exercise causes damage, but the extent of damage varies by time of day. Morning training with satellite cells present may result in less structural damage (dystrophin loss) than afternoon training, potentially due to lower force generation. This suggests morning might be a safer time for high-intensity eccentric work if injury prevention is the goal.

ModerateSupportsMEDIUM confidence
Morning-SC þ animals... after eccentric injury, exhibited ~30% less force-loss and ~50% less dystrophinnegative fibers versus SC- counterparts
Ryan E. Kahn et al. · American Journal of Physiology-Cell Physiology · 2024

Why this rating

Statistically significant findings (P < 0.05) for injury markers, but limited sample size (n=3-5/group for some metrics) and ex vivo nature.

Source

Time-of-day effects on ex vivo muscle contractility following short-term satellite cell ablation

Ryan E. Kahn et al. · American Journal of Physiology-Cell Physiology · 2024

DOI 10.1152/ajpcell.00157.2024

mechanism_only · n=24Cited 8×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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