Take two bands and loop them around the bottom of the power rack. (You can see in the picture, I placed mine on the back posts, but you can use the front or any other secure post available.) Cross the band on the right side over to your opposite shoulder. Do the same for the other band so that you have created an "X" with the bands. This is important, otherwise the bands will slide off your shoulders.
You will also need something to put your feet against. I placed a 2x4 in front of the platform. You can use the front of an Olympic stlye platform as it is raised approx. 4 inches off the ground.
Bend your knees and place your hands on the ground. Get in a good squat position to start. Using your legs and hips, push off the boards, and fully extend your body. Your hands will also hit the ground at this time. Release and go back to the starting position.
Once you find a rhythm, this is a great exercise. It is a great alternative to squat jumping with heavy weights. It is also great for wrestlers, swimmers and sprinters.