Anabolic processes in human skeletal muscle: restoring the identities of growth hormone and testosterone.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic arguments and prior study findings without systematic review methodology.
PubMed 20959702 · doi:10.3810/psm.2010.10.1814
What was done
This narrative review synthesized physiological mechanisms of action for testosterone and growth hormone (GH) in skeletal muscle. The authors evaluated evidence regarding whether transient, exercise-induced systemic elevations in endogenous testosterone and GH stimulate post-exercise intracellular anabolic signaling, myofibrillar protein synthesis, and resistance-training-induced muscular hypertrophy versus the role of intrinsic, local muscular mechanisms.
What was found
The abstract reports no quantitative values or effect sizes. The authors describe findings indicating that exercise-induced transient hormonal elevations do not enhance intracellular anabolic signaling markers or the acute post-exercise elevation of myofibrillar protein synthesis. Additionally, cited training data indicate that systemic post-exercise increases in GH and testosterone availability are not necessary for, and do not enhance, adaptations in strength or muscle hypertrophy compared to local contractile mechanisms.
Why it matters
This paper challenges the common paradigm that resistance training protocols must be structured to maximize acute systemic hormonal spikes to achieve optimal muscular hypertrophy. It clarifies that localized contractile mechanisms primarily drive muscular adaptations in healthy individuals.
Limits
The abstract is a narrative review rather than a systematic review or primary empirical report, providing no specific sample sizes, participant demographics, quantitative statistics, or search methodology. Details regarding specific exercise interventions and measurement techniques are not provided in the abstract.
Cited by
- supports Exercise increases systemic levels of growth hormone and testosterone.