Abejoye, Israel2026-07-222026-07-222026-07-172026-07-182026-07-22http://hdl.handle.net/1993/39892Design: A repeated measures mixed-design ANOVA was used to evaluate the effects of two different tempos of conditioning activities using the back squat exercise on countermovement jump performance in young adults who were resistance-exercise trained. Methods: Fifty-four healthy untrained participants completed two experimental sessions and one control session across three separate days. Each ∼32-minute session began with a standardized warm-up, followed by a baseline countermovement jump (CMJ). After baseline, participants performed their assigned protocol: for the dynamic muscle action condition (DMAC), 3 sets of 10 repetitions (reps) at 60% one repetition maximum (1RM) with tempo <1/0/<1/0 seconds; for the traditional muscle action condition (TMAC), 3 sets of 5 reps at 60% 1RM with tempo 2/0/2/0 seconds; and for the control condition (CON) [no conditioning activity (CA)]. A post-CMJ was recorded immediately after each protocol. Results: A total of 162 trials were collected, but 150 valid trials were included after 12 trials were excluded due to ForceDecks errors affecting 4 participants’ data. Using repeated measures mixed-design ANOVA with Greenhouse-Geisser correction, take-off peak force (TPF) did not differ across conditions, F(1.48, 70.80) = 0.045, p = .913 and TPF also did not change across time points. Males outperformed females in all conditions and at both time points p < .001. Concentric impulse (CI) showed no main effect of condition, but there was a condition × sex interaction with males outperforming females in all three conditions, p < .001. A condition × time interaction: post-CI improved compared to pre-CI for DMAC, while CON post-CI worsened compared to baseline CMJ. Peak power (PP) showed no main effect of condition or time, yet a significant three-way interaction driven by sex emerged, with males outperforming females across conditions and time points, p < .001. Jump height (JH) showed a significant condition × time interaction. Post-JH stayed the same as pre-JH for both CAs, but CON post-JH dropped significantly compared to TMAC post-JH, p = .020, and compared to CON pre-JH, p = .003. Conclusions: Slow tempo did not significantly improve participants’ CI, however, fast tempo increased participants’ CI, and CON decreased participants’ CI. Post-JH performance dropped drastically in CON, while both slow and fast tempo conditions only helped participants maintain post-JH performance.engPost Activation Performance EnhancementResistance excerciseRandomized Controlled TrialsConditioning ActivityResistance training