Just doing weightlifting without taking BCAAs causes some changes in muscle proteins: p70 S6 kinase gets partially activated but not fully, Akt decreases, and GSK-3 stays the same.
Scientific Claim
Resistance exercise alone leads to partial phosphorylation of p70 S6 kinase without activating the enzyme, decreased Akt phosphorylation, and no change in GSK-3 in human skeletal muscle.
Source Excerpt
“Exercise without BCAA intake led to a partial phosphorylation of p70 S6 kinase without activating the enzyme, a decrease in Akt phosphorylation, and no change in GSK-3.”
Evidence from Studies
Supporting Studies
Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise.
The study directly reports the effects of resistance exercise alone (without BCAAs) on various phosphorylation markers in human skeletal muscle. This is a descriptive finding of what happens during recovery from exercise without supplementation.
⚠️ Overstated
The study design is unclear (Level 5 evidence), and the claim uses 'leads to' which implies causation. The study only shows association between exercise and these changes.
More accurate phrasing:
“Resistance exercise alone is associated with partial phosphorylation of p70 S6 kinase without activating the enzyme, decreased Akt phosphorylation, and no change in GSK-3 in human skeletal muscle.”