Hamstring, Calves, Quadriceps
Stand facing the box, your feet within roughly six inches of its side. Your feet should be about hip-distance apart, your knees and hips slightly bent in an athletic stance.
Bend your knees and press your hips back as you swing your arms behind you in a smooth motion.
Explode through the balls of your feet, jumping straight up into the air, swinging your arms up and forward as you fully extend your knees and hips to get as much height as you can with your jump.
At the height of your jump, bend your knees and hips to draw them forward to be able to land on top of the box.
Land with both feet at the same time atop the box, leading with the balls of your feet, following with your heels.
Step—don't jump—carefully off the box and reset for the next repetition.
Progressions And Regressions