Differences in Mechanical Output between One Repetition Maximum- and Body Mass-Based Load Determination in The Behind-Neck Push Jerk

Body mass (BM) can be used to prescribe loads for some weightlifting derivatives, as an alternative to the one-repetition maximum (1RM). However, the effectiveness of this method has not been investigated in weightlifting overhead pressing derivatives. The primary aim of the study was to investigate the effect of loads determined with percentages of 1RM and BM on kinetic and kinematic characteristics in the behind-neck push jerk (BNPJ). Sixteen recreational male athletes were recruited and performed 3 repetitions of the BNPJ from 40% to 80% of their 1RM and BM, respectively. Two force plates were used to collect kinematic (peak velocity, mean velocity, phase time) and kinetic variables (peak force, mean force, peak power, mean power, and impulse) in the concentric phase. A two-way repeated measures analysis of variance assessed the interaction and the main effect (approaches and intensities) on the dependent variables. The level of significance was set at p ≤ 0.05. No significant interactions existed between the approaches and intensities in all variables. The main effect approach was not significant in all the kinematic variables, but significant intensity main effects were found. Significant approach and intensity main effects were found in all kinetic variables. All kinetic variables were greater in the 1RM-based approach compared to the BM-based approach. BM can serve as a practical alternative to 1RM for load prescription in the BNPJ when targeting kinematic characteristics. However, 1RM-based loading may be more suitable for maximizing kinetic outputs.