Methods: Five hundred eighty-five subjects (342 women, 243 men) were tested at one of eight study centers. Isometric (MVC)
and dynamic strength (one-repetition maximum (1RM)) of the elbow flexor muscles of each arm and magnetic resonance imaging
(MRI) of the biceps brachii (to determine cross-sectional area (CSA)) were assessed before and after 12 wk of progressive dynamic
resistance training of the nondominant arm