Background An important number of sport modalities sustain its performance in the capacity to repeat efficiently a sport movement without fatigue. However, it is a fact that this mechanism will appear and affect the athletes' velocity magnitudes. The aim of this study was to compare the Peak Velocity (PV) in two protocols: Traditional Training (TT) vs. 20 s inter-repetition rest (IRR) with the Optimal Load (OL) for the maximal Power output (OL: 50.7±8.0% of 1-RM).

Methods Fifteen male, physical education students, participated in this study (age: 23.1±1.6 years; height: 177.1±7.7 cm; mass: 76.2±9.2 kg; 1-RM: 93.8±14.3 kg; 1-RM/mass: 1.24±0.21). After the validation of the bench press 1-RM and determination of OL, all participants performed two sets of work: TT (1 set×continuous repetitions to failure) and IRR (1 set×15 repetitions with 20 s rest between repetitions).

Results In the TT, VP decreased significantly from the third repetition (3.7±1.2 repetition) with loses of 17.8% (p≤0.014; ES: -0.53; IC: 0.046–0.243) (1st repetition: 0.75±0.18 m•s-1; 3rd repetition: 0.62±0.14 m•s-1). In IRR, VP magnitudes did not decrease significantly along the 15 repetitions (1st repetition: 0.67±0.23 m•s-1; 15th repetition: 0.64±0.12 m•s-1). Also, among our sample participants, there were no correlations found between VP and strength levels. Conclusions: While in TT fatigue is manifested in significant velocity loses, in IRR the movement mechanical efficiency and the mechanical parameters remain stable along the fifteen assessed repetitions. Consequently, we can conclude that the addition of inter-repetition rests (20 s) allows the performance of a higher number of movements without significant alterations or presence of fatigue along the set.