Research

Mixed

Short-term muscle disuse atrophy (4 days) in humans is driven by declines in muscle protein synthesis (MPS), not by increased muscle protein breakdown (MPB).

If you are immobilized or inactive for a few days, your muscle loss is caused by a drop in your body's ability to build new muscle protein, not by an increase in muscle destruction. To mitigate this, interventions should focus on stimulating muscle protein synthesis (e.g., through protein intake or resistance stimuli if possible) rather than just trying to block breakdown pathways.

GoodRefutesHIGH confidence
Human skeletal muscle disuse atrophy is driven by declines in MPS, not increases in MPB.
Matthew S. Brook et al. · Journal of Cachexia Sarcopenia and Muscle · 2022

Why this rating

High-quality human study with gold-standard tracer methods (D2O and amino acid tracers) and bilateral control design.

Source

Declines in muscle protein synthesis account for short‐term muscle disuse atrophy in humans in the absence of increased muscle protein breakdown

Matthew S. Brook et al. · Journal of Cachexia Sarcopenia and Muscle · 2022

DOI 10.1002/jcsm.13005

crossover · n=9Cited 65×
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DOI resolved against Crossref · corpus check 2026-06-10

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