Mechanical Output and Post-exercise Jump Responses to Percentage-Based, Repetitions-in-Reserve, and Velocity-Based Back-Squat Training in Trained Sprinters: A Randomized Crossover Study

The purpose of this study was to compare acute mechanical output and immediate post-exercise jump responses among percentage-based training (PBT), repetitions in reserve (RIR), and velocity-based training (VBT) during the back-squat exercise in trained sprinters. Eighteen trained male 100-m sprinters completed all three conditions in randomized order using a within-participant crossover design, with at least 72 h between trials. Each condition began at 80% of one-repetition maximum and comprised of five sets with a maximum of five repetitions per set. Bilateral force plates recorded vertical ground-reaction force during squatting and during pre- and post-exercise countermovement jump (CMJ) and squat jump (SJ) tests. Completed repetitions averaged 25.00, 25.00, and 24.06 per session under PBT, RIR, and VBT, respectively; session volume loads also differed among protocols. No statistically significant overall condition effects were detected for relative peak vertical force (p = 0.348), mean positive vertical impulse (p = 0.262), CMJ jump height (p = 0.969), CMJ modified reactive strength index (p = 0.894), or SJ jump height (p = 0.740). The present study found that VBT resulted in fewer completed repetitions and lower session volume load than PBT and RIR. No significant between-protocol differences were detected in session-level mechanical output or immediate postexercise jump responses.