The Claim
The phosphorylation of p70s6k at Thr389 in muscle tissue is strongly correlated with the proportion of fast-twitch muscle fibers in resistance-trained men following both light and heavy resistance exercise.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In resistance-trained men, the level of p70s6k phosphorylation at Thr389 in muscle tissue is directly related to the percentage of fast-twitch muscle fibers, regardless of whether the exercise load is light or heavy.
See the scientific wording
The phosphorylation of p70s6k at Thr389 in muscle tissue is strongly correlated with the proportion of fast-twitch muscle fibers in resistance-trained men after both light and heavy resistance exercise, suggesting fiber-type composition may influence anabolic signaling intensity.
Muscles with more fast-twitch fibers generate stronger mechanical tension and metabolic stress during resistance exercise, which turns on a growth signal pathway that activates p70s6k, leading to more protein building in those fibers.
What the research says
1 studyPeople with more fast-twitch muscle fibers—those that power quick, strong movements—show a stronger muscle-growth signal after lifting weights, whether they use light or heavy weights. This study found that link clearly in men who trained with both types of loads.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.