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.
Claim Language
Language Strength
definitive
Uses definitive language (causes, prevents, cures)
The claim uses the verb 'increases' which implies a direct, certain cause-and-effect relationship without hedging. The use of precise percentages ('17–18%', '21%') and the phrase 'regardless of whether' further reinforces a definitive tone, suggesting the outcome is guaranteed under the stated conditions.
Context Details
Domain
exercise_science
Population
human
Subject
untrained young men
Action
increases
Target
pectoralis major clavicular muscle thickness by approximately 17–18% and sternocostal thickness by approximately 21%
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Pectoralis Clavicular and Sternocostal Thicknesses Increase Similarly in Response to One and Three Sets of Pec Deck Resistance Training in Untrained Young Men
The 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.