The present study was designed to evaluate the voluntary post-activation potentiation (PAP) effects of moderate (MI) or high intensity (HI) back squat exercises on countermovement jump (CMJ) performance across multiple sets of a contrast training protocol. Sixty resistance-trained male subjects (age, 23.3 ± 3.3 y; body mass, 86.0 ± 13.9 kg; parallel back squat 1-repetition maximum [1-RM], 155.2 ± 30.0 kg) participated in a randomized, cross-over study. After familiarization, the subjects visited the laboratory on three separate occasions. They performed a contrast PAP protocol comprising three sets of either MI (6×60% of 1-RM) or HI back squats (4x90% of 1-RM) or 20 s of recovery (CTRL) alternated with seven CMJs that were performed at 15 s, and 1, 3, 5, 7, 9 and 11 min after the back squats or recovery. Jump height and relative peak power output recorded with a force platform during MI and HI conditions were compared to those recorded during control condition to calculate the voluntary PAP effect. CMJ performance was decreased immediately after the squats but increased across all three sets of MI and HI between 3 – 7 minutes post-recovery. However, voluntary PAP effects were small or trivial and no difference between the three sets could be found. These findings demonstrate that practitioners can use MI and HI back squats to potentiate CMJs across a contrast training protocol, but a minimum of 3 min of recovery after the squats is needed to benefit from voluntary PAP.