Barbell load distribution and lifting velocity affect bench press exercise volume and perceived exertion

OBJECTIVE: The intensity of barbell bench press exercise is generally prescribed as the load to be lifted for a specific number of repetitions; however, other factors (e.g., execution velocity) can affect bench press exercise intensity. Moreover, no study assessed whether load distribution (i.e., the distance between the disc stacks on the two sides of the barbell) affects exercise intensity. The present study aims to assess how different combinations of load, velocity, and barbell load distribution affect the number of repetitions to failure (REP(failure)), and rating of perceived exertion (RPE(fatigue)) and number of repetitions (REP(fatigue)) at fatigue onset. METHODS: Ten males (age 23.3±1.8 years) performed bench press exercises to exhaustion using random combinations of three loads (50%, 65%, and 80% of 1 repetition maximum), three execution velocities (50%, 70%, and 90% of maximal concentric velocity), and two load distributions (narrow and wide). Three separate three-way repeated-measures ANOVAs were performed to assess the effect of load, velocity, and load distribution on REP(failure), RPE(fatigue), and REP(fatigue) expressed as a percentage of REP(failure). RESULTS: REP(failure) was affected by load (p<0.001), velocity (p<0.001), and distribution (p = 0.005). The interactions between load and velocity (p<0.001) and load and distribution (p = 0.004) showed a significant effect on REP(failure), whereas the interaction between velocity and distribution was not significant (p = 0.360). Overall, more REP(failure) were performed using lower loads, higher velocities, and a wider distribution. RPE(fatigue) and REP(fatigue) were affected by load (p<0.001 and p = 0.007, respectively) and velocity (p<0.001 and p<0.001, respectively), and not by distribution (p = 0.510 and p = 0.571, respectively) or the two-way interaction effects. Overall, using higher loads yielded higher RPE(fatigue) but lower REP(fatigue), while RPE(fatigue) and REP(fatigue) were higher when slower velocities were used. CONCLUSION: The current investigation shows that not only load but also velocity and barbell load distribution may influence bench press training volume and perceived exertion.