RPE vs. Percentage 1RM Loading in Periodized Programs Matched for Sets and Repetitions

Purpose: To investigate differences between rating of perceived exertion (RPE) and percentage one-repetition maximum (1RM) load assignment in resistance-trained males (19-35 years) performing protocols with matched sets and repetitions differentiated by load-assignment. Methods: Participants performed squats then bench press 3x/weeks in a daily undulating format over 8-weeks. Participants were counterbalanced by pre-test 1RM then assigned to percentage 1RM (1RMG, n = 11); load-assignment via percentage 1RMs, or RPE groups (RPEG, n = 10); participant-selected loads to reach target RPE ranges. Ultrasonography determined pre and post-test pectoralis (PMT), and vastus lateralis muscle thickness at 50 (VLMT50) and 70% (VLMT70) femur-length. Results: Bench press (1RMG + 9.64 +/- 5.36; RPEG + 10.70 +/- 3.30 kg), squat (1RMG + 13.91 +/- 5.89; RPEG + 17.05 +/- 5.44 kg) and their combined-total 1RMs (1RMG + 23.55 +/- 10.38; RPEG+ 27.75 +/- 7.94 kg) increased (p<0.05) in both groups as did PMT (1RMG + 1.59 +/- 1.33; RPEG + 1.90 +/- 1.91mm), VLMT50 (1RMG + 2.13 +/- 1.95; RPEG + 1.85 +/- 1.97mm) and VLMT70 (1RMG + 2.40 +/- 2.22; RPEG + 2.31 +/- 2.27mm). Between-group differences were non-significant (p > 0.05). Magnitude-based inferences revealed 79, 57, and 72% chances of mean small effect size (ES) advantages for squat; ES 90% confidence limits (CL) = 0.50 +/- 0.63, bench press; ES 90% CL = 0.28 +/- 0.73, and combined-total; ES 90% CL = 0.48 +/- 0.68 respectively, in RPEG. There were 4, 14, and 6% chances 1RMG had a strength advantage of the same magnitude, and 18, 29, and 22% chances, respectively of trivial differences between groups. Conclusions: Both loading-types are effective. However, RPE-based loading may provide a small 1RM strength advantage in a majority of individuals.