The Claim
In untrained young men, 12 weeks of pec deck resistance training increases pectoralis major clavicular muscle thickness by approximately 17–18% and sternocostal thickness by approximately 21%, regardless of whether one or three sets are performed per session.
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.
If you're a young guy who hasn't trained before and you do pec deck exercises for 12 weeks, your chest muscles will get thicker—about 17–18% thicker in the upper part and 21% thicker in the lower part—no matter if you do just one set or three sets each workout.
See the scientific wording
In untrained young men, 12 weeks of pec deck resistance training increases pectoralis major clavicular muscle thickness by approximately 17–18% and sternocostal thickness by approximately 21%, regardless of whether one or three sets are performed per session.
What the research says
1 studyThe study found that doing either one or three sets of pec deck exercises for 12 weeks made the chest muscles grow by about the same amount — exactly what the claim says.
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.