Upper body push power is a critical factor in numerous sports, and coaches often seek effective methods like conditioning activities (CA) to acutely enhance performance through post-activation performance enhancement (PAPE). While various CAs have been studied, comparisons between opposite ends of the intensity spectrum, high-load versus low-load ballistic activities, remain unclear in upper body research. Twenty-eight trained male athletes (age 24.86 ± 2.62 years) completed three conditions in a randomized within-subject crossover design: High-Load Bench Press (HLBP), Ballistic Medicine-Ball Throw (BMT), and an active Control Condition (CC). Participants were randomly allocated to one of the six possible condition orders (i.e., all permutations of HLBP, BMT and CC). Bench Press Throw performance (40% of 1RM) was assessed at baseline, 5 min and 10 min post-condition using the 1080 Quantum system. Peak Power Output (PPO) and Average Power Output (APO) and Peak Velocity (PV) formed the confirmatory family; the hypotheses were tested with difference-in-change contrasts between HLBP and BMT, with Holm-Bonferroni correction across the six contrasts (three outcomes × two time points). Average Velocity, Time to Peak Power Output and Time to Peak Velocity were exploratory. Significant Condition × Time interactions were found for PPO (p = 0.023, η²p = 0.099) and PV (p = 0.004, η²p = 0.134). In the confirmatory contrasts, the change from baseline to 5 min in HLBP differed from that in BMT by -97.7 W for PPO (95% CI -159.4 to -35.9; dz = -0.61; Holm-adjusted p = 0.016) and by -0.086 m·s^-1 for PV (95% CI -0.137 to -0.035; dz = -0.65; adjusted p = 0.011). No contrast was significant at 10 min, and APO did not differ at either time point. Within conditions, only HLBP changed relative to its own baseline, decreasing at 5 min for PPO (-67 W, ≈3.9%, dz = -0.61) and PV (-0.071 m·s^-1, ≈2.7%, dz = -0.74), with partial recovery at 10 min. For these two outcomes neither BMT nor CC differed from baseline, and BMT did not differ from CC. Although the standardized within-subject effects were moderate, the absolute changes were small and of limited practical relevance. Contrary to the first hypothesis, HLBP did not outperform BMT; the direct contrast at 5 min was significant in the opposite direction. The second hypothesis, which predicted greater peak velocity after BMT than after HLBP, was supported by the confirmatory contrast at 5 min. This difference arose from a decrement after HLBP rather than from potentiation after BMT, which changed neither from its own baseline nor relative to the control condition, and the result should therefore not be read as evidence of potentiation. Neither conditioning activity produced acute performance enhancement under the investigated protocols, suggesting that the fatigue induced by two sets at 90% 1RM outweighed any potential potentiation effects within that timeframe.