If you're a young guy who's never lifted weights before and you do pec deck exercises, your upper and lower chest muscles will grow the same amount—no one part gets bigger than the other.

A randomized controlled trial in untrained young men comparing pec deck training against a control group, with pre- and post-intervention MRI scans measuring cross-sectional area of the clavicular and sternocostal heads of the pectoralis major, using standardized training volume and frequency over 8–12 weeks.

A within-subjects study where untrained young men perform pec deck training unilaterally (one arm) while the contralateral arm serves as internal control, with MRI quantification of regional hypertrophy in both clavicular and sternocostal heads after 10–12 weeks of training.

An observational cohort of untrained young men performing pec deck training over 12 weeks with varying volumes, where regional pectoralis major hypertrophy is measured via MRI and analyzed for differences between clavicular and sternocostal regions across individuals.

A case series of 10–15 untrained young men undergoing pec deck training for 12 weeks with serial MRI scans to document regional hypertrophy patterns in the pectoralis major, focusing on clavicular vs. sternocostal changes.

A computational model simulating muscle activation patterns during pec deck exercises to predict differential recruitment of clavicular vs. sternocostal pectoralis major fibers and infer potential hypertrophy differences.