Acute Effects of Using Individual Velocity Targets to Regulate Resistance Training Load

Abstract

We determined the acute biomechanical, physiological, and perceptual effects of using individualised velocity targets (IVT) or a percentage of one repetition maximum (%1RM) to regulate resistance training load. Thirty-nine resistance-trained adults (age: 21.8±3.2 years) completed two strength training sessions (five sets of five free-weight back squats) in a randomised, counterbalanced order. The %1RM session involved using a fixed load at 80% 1RM, whereas the IVT session used a modifiable load corresponding to the mean velocity at 80% 1RM. Kinetic and kinematic data and rating of perceived exertion (RPE) were recorded during training sessions. Countermovement jump (CMJ) height and blood lactate concentration were measured pre- and post-session, and perceived muscle soreness and fatigue were measured 24-hours post-exercise using 10-point Likert scales. We used null-hypothesis significance testing to test for differences between conditions and two one-sided tests (TOST) to assess equivalence. IVT significantly increased sessional mean velocity (mean difference=0.05 m·s^-1), peak velocity (0.08 m·s^-1), mean power (54.4 W), and peak power (141 W), while significantly reducing barbell load (-2.7 kg), RPE (-0.49), time under tension (-0.13 s), and velocity loss (0.02 m·s^-1), compared to %1RM. IVT and %1RM had equivalent effects on post-exercise perceived fatigue (0.11, 10-point-scale) and pre-post changes in blood lactate (-0.50 mmol/L) and CMJ height (-0.75 cm). In conclusion, using individualised velocity targets to regulate resistance training load increases movement velocity in repeated sets of free-weight back squats but does not meaningfully influence markers of post-exercise fatigue compared to %1RM.