Best done on jerk racks, but can be done in a power rack if there is no concern about possible damage to the barbell.
Set the height of the blocks or the pins of a power rack at a level that places the barbell on your back at approximately quarter-squat depth. Place the feet either in the pulling or receiving position depending on the goal, and jump as high as possible. Hold the bar down against the back tightly to prevent it from slipping or bouncing, and don't try to stop or decelerate the weight as it returns - squat under it with little resistance to reset it on the blocks or pins.
Catalyst Athletics is a USA Weightlifting team of competitive Olympic-style weightlifters. We are currently recruting new lifters and offer sponsorship opportunities.