Comparison of Two Resistance Training Protocols, 6RM versus 12RM, to Increase the 1RM in Healthy Young Adults. A Single-Blind, Randomized Controlled Trial

Purpose The purpose of the study is to compare the effect in healthy young adults of two resistance training protocols, six‐repetition maximum (RM) versus 12RM on maximum strength (1RM). Method A single‐blind, randomized controlled trial was used in the study. Sixty‐two healthy physical therapy students, with age (mean [+standard deviation]) 23 (+2.6) years, weight 67.4 (+11.7) kg and height 171.7 (+8.4) cm, of both genders who were recreationally active, but not training systematically, volunteered to participate in the study. They were randomized into two groups (group 1: 24 women and 8 men; group 2: 23 women and 7 men) by a block randomization procedure that ensured equal gender distribution. Sealed envelopes were used to conceal allocation to groups. Interventions Group 1 did three sets of 6RM of each exercise, and group 2 did three sets of 12RM. Both groups performed the exercises twice per week for 8 weeks with 3 minutes rest between sets and exercises. Primary outcomes were maximum strength defined as one‐repetition maximum squat (1RMSq) for lower‐body strength and bench press (1RMBp) for upper‐body strength. Secondary outcomes were body weight and Uro Kaleva Kekkonen (UKK) Fitness Index. Results Both groups increased strength significantly (p