Setup
Position upper back on a plyobox with chin tucked slightly, feet about shoulder width apart and knees bent with glutes resting on the floor, barbell with a barbell pad/foam resting on in your hip crease with overhand grip, engage your core.
Movement
Engage your glutes and drive your hips up pushing through your heels and keeping your back straight and pivoting through your upper back, when your shoulders, hips and knees are in a straight line stop the movement. Maintain your shins in a vertical position to bias the glutes. Slightly drop out of the end of the movement, and then return to the end of the movement, completing as many pulses as prescribed. Return to the start
Tip
Keep your chin tucked like you are holding an orange between your chin and sternum.
Do not flare out your ribs
Feet far apart will bias the hamstrings, closer together will bias the quads
Squeeze the glutes hard at the top of the movement
Do not let your knees cave in
Maintain a neutral spine position, do not overarch your low back