Predicting One Repetition Maximum in Novice Males: An RPE-Based Bench Press Model

Abstract

This study aimed to estimate one repetition maximum (1RM) of healthy males based on the Rating of Perceived Exertion (RPE) in bench press movement and to provide a particular predictive equation. Seventy healthy males (Age: 24.93 ± 0.64 years; BMI: 25.04 ± 0.35 kg/m2) with no previous experience of resistance training performed 1RM of bench press with closed eyes and then chose a number to determine the intensity by RPE scale of 1–10 (CR1-10 scale). The intensity of this repetition was randomly selected based on the percentages of 1RM: 60%, 65%, 70%, 75%, 80%, 85%, 90% and 95%. A special prediction equation was provided based on a mathematical model using the weight lifted, RPE, and RPE coefficient. Moreover, the standardized testing protocol of 1RM (STP) and Brzycki equation protocol (BEP) were used to verify the validity of the RPE equation. Predictive equations were produced and cross-validated using repeated k-fold cross-validation by stepwise multiple linear regression. BEP and STP did not differ significantly from RPE-equation in predicting 1RM (p > 0.05). Based on the BEP and STP, a 1RM attempt for inexperienced males resulted in 74.20 ± 2.24 kg and 77.47 ± 2.17, respectively, while the RPE equation produced 77.86 ± 2.58 kg. There were significant results for linear regression (p = 0.001). Pearson correlation coefficients between BEP and STP with predicted 1RM were 0.99. The new method of 1RM based on RPE performed well in 1RM performance in inexperienced males, and it appeared safe, accurate, and time-effective.