Impact of Percentage-based Versus Autoregulated-based Load Prescription on Maximal Strength

Researchers and practitioners use the resistance training-specific rating of perceived exertion (RPE) scale for individualization of training load prescription. However, an intervention to compare traditional percentage-based load prescription versus RPE-based loading for strength adaptations has not been conducted. PURPOSE: To compare changes in one-repetition maximum (1RM) strength of the back squat and bench press between percentage-based training (PBT) and autoregulated-based training (ABT) via RPE. METHODS: Eleven males (age: 23±4 yrs, body mass: 77.4±7.7 kg, body fat: 9.5±3.8%) with at least two yrs. of training experience and a minimum 1RM of 1.5 and 1.25x bodyweight on the squat and bench press respectively, were assigned to one of two groups: PBT (n=6) or ABT (n=5) for 8 weeks. Forty eight hours following pre-testing 1RM both groups performed the squat and bench press 3x/wk. on non- consecutive days (i.e. Mon., Wed., Fri.) using the same number of sets and repetitions following an undulating resistance training program, which linearly increased load and decreased repetitions throughout. Weeks 1-3 consisted of 8, 6, and 4 repetitions on Mon., Wed., and Fri., while weeks 4-5 consisted of 7, 5, and 3 repetitions during the week, with 6, 4, and 2 repetitions being performed during weeks 6-7. Week 8 served as a taper with 4 and 3 repetition days on Mon. and Wed. and post-testing on Fri. Load increased during each week in PBT from 65, 70, and 75% in week 1 to 82.5-92.5% of 1RM in week 7. In ABT there was no prescribed load but subjects were instructed to select a load, in which the set ended with a 5-7RPE in week 1 and progressing to an 8-10RPE in week 7. A 2x2 repeated measures ANOVA was used with significance set at p≤0.05. RESULTS: There was a time effect (p<0.01) for 1RM squat (141.00±22.49 to 153.75±20.40kg; +9.46%), bench press (109.08±15.89 to 116.67±14.61kg; +7.22%), and total strength-TS (250.08±32.30 to 270.42±29.62kg; +8.39%) in PBT, and for 1RM squat (152.20±21.65 to 171.30±24.97kg; +12.52%), bench press (123.00±11.31 to 133.70±14.82kg; +8.58%), and TS (275.20±30.24kg to 305.00±37.61kg; +10.71%) in ABT. However, no significant group differences existed for squat (p=0.31), bench (p=0.11) or TS (p=0.16). CONCLUSION: Our findings indicate that both PBT and ABT are equally effective at increasing maximal strength.