Can Force-Velocity Profiles Using a Trap-Bar or Body Jump Height Ratio Serve as Alternatives to Those Using a Straight-Bar?

Abstract

Background Vertical force-velocity profiles (FVP) derived from squat jumps (SJ) or countermovement jumps (CMJ) with straight-bars (SB) offer valuable insights into neuromuscular function, yet concerns arise regarding spinal loading and injury risks during high-load exercises. Aims To evaluate (i) differences and relationships between variables using conventional FVP of SJs with SB and trap-bar (TB), and (ii) potential relationships between FVP variables and those from body weight jumps. Methods The randomized crossover design involved 15 participants performing SJ, CMJ without arm swing (CMJ w/o AS), CMJ with arm swing (CMJ w/ AS), and loaded SJ with additional body weights (40%, 60%, and 80%) under SB and TB conditions. FVP variables including theoretical maximum force (F0), velocity (V0), power (Pmax), slope of the force-velocity linear relationship (Sfv), and force-velocity imbalance (FVimb) were calculated with multiple SJs. The CMJ w/o AS height to SJ height ratio (CMJ/SJ) determined the explosive strength deficit. Results Loaded SJ height was significantly higher in the TB condition than that in SB (p < 0.050). F0 and FVimb values calculated were significantly higher with TB (p < 0.010), whereas V0 and Sfv were significantly higher with SB (p < 0.010). FVimb was significantly and positively correlated with both conditions (p = 0.007), and the correlation between Sfv and CMJ/SJ in the TB group was also significant (p = 0.041). Conclusions FVP calculated with multiple SJs using SB and TB can be used interchangeably, while CMJ/SJ could partially serve as an alternative to FVP.