Do Lower Repetition Targets in Resistance Training Produce Greater Gains? A Randomized Controlled Trial Using a Monozygotic Twin Design

INTERVENTION: Group 1: Set10: Participants completed 13 weeks of fully supervised progressive resistance training targeting 10 repetitions per set. Sets were performed to momentary concentric failure. Group 2: Set20: Participants completed 13 weeks of fully supervised progressive resistance training targeting 20 repetitions per set. Sets were performed to momentary concentric failure. CONDITION: Resistance training adaptations in healthy adults PRIMARY OUTCOME: Changes in maximal strength (one‐repetition maximum in the back squat and bench press) and muscle thickness of the rectus femoris and vastus lateralis assessed by ultrasound from pre‐ to post‐intervention (13 weeks). SECONDARY OUTCOME: Changes in body mass, body composition (fat‐free mass, muscle mass, and fat mass) assessed by bioelectrical impedance analysis, and arm and leg circumferences from pre‐ to post‐intervention (13 weeks). INCLUSION CRITERIA: Monozygotic twin pairs, medically suitable for participation in a progressive resistance training program, willing to comply with the prescribed training and dietary protocol. Previous resistance training experience was not required.