A review of resistance training-induced changes in skeletal muscle protein synthesis and their contribution to hypertrophy.
Level 5 - mechanism / opinion, no new human data
Narrative review of human mechanistic physiological studies without systematic review methodology
PubMed 25739559 · doi:10.1007/s40279-015-0320-0
What was done
This narrative review synthesized published evidence evaluating acute skeletal muscle protein synthesis (MPS) responses to resistance exercise and nutrition across untrained and trained states, as well as during different phases of resistance training programmes, to assess how these responses relate to chronic muscle hypertrophy.
What was found
The abstract reports no numerical data or effect sizes. Qualitatively, it reports that acute post-exercise MPS responses in untrained individuals do not correlate with subsequent chronic hypertrophy. With resistance training, post-exercise increases in MPS peak earlier and are shorter-lived compared to untrained states, resulting in an overall smaller and dampened muscle protein synthetic response.
Why it matters
It clarifies that acute MPS responses measured in untrained individuals do not directly predict chronic muscle hypertrophy because training status dynamically alters the time course and magnitude of protein accretion.
Limits
As a narrative review, it lacks systematic search methodology, meta-analytic pooling, or risk-of-bias assessment. No numerical data or sample sizes are provided in the abstract, and the exact timeline of when MPS dampening occurs during training remains unknown.