This study compared differences between ballistic jump squat (B) and nonballistic back squat (NB) force, velocity, power, and relative acceleration duration, and the effect that the method used to identify the positive lifting phase had on these parameters. Ground reaction force and barbell kinematics were recorded from 30 resistance trained men during B and NB performance with 45% 1RM. Force, velocity, and power was averaged over positive lifting phases identified using the traditional peak barbell displacement (PD) and positive impulse method. No significant differences were found between B and NB mean force, and mean power, but B mean velocity was 14% greater than the NB equivalent. Positive impulse mean force was 24% greater than PD mean force, and B relative acceleration duration was 8.6% greater than the NB equivalent when PD was used to identify the end of the positive lifting phase. These results challenge common perceptions of B superiority for power development.