Starting Position: Place a 6-12" raised platform or box on the floor 3-6" in front of your feet on a non-slip surface. Stand with your feet hip-width apart or closer, arms by your sides, depress and retract your scapulae (pull your shoulders down and back) without arching your low back, and "brace" (engage your abdominal / core muscles) to stiffen your spine.
Downward Phase: Begin your downward phase by first shifting your hips backwards then slowly moving downwards to create a hinge-like movement at your knees. Continue to lower yourself until your feel your heels about to lift off the floor. Try to maintain a flat back by bending forward at the hips, keep your head facing the box and position your arms where comfortable or where they offer the greatest degree of balance support.
Jumping Movement: With ONLY a very brief pause at the bottom of your downward phase, explode upwards through your lower extremity while swinging your arms forward and jumping onto the top of the raised platform or box, achieving triple extension (pushing and extending your ankles, knees and hips simultaneously). As you jump into the air, keep your feet level with each other and parallel with the floor.
Landing: The most important components of the landing phase on a raised platform or box are correct foot position and avoiding excessive forward movement in your lower extremity which places additional stresses upon your knees.
Attempt to land softly and quietly on the mid-foot, rolling backwards quickly towards the heels to create a level foot, parallel with the surface. Always push your hips backwards and drop your hips to absorb the jumping forces. Avoid locking your knees and quads on your landing as this may lead to potential knee injuries.
Land with your trunk inclined slightly forward, head aligned with your spine and back rigid or flat. Keep your abdominal / core muscles engaged, stiffening your torso to protect your spine.
Exercise Variation: As you develop your jumping and landing skills, you can progress the exercise intensity and complexity by: (1) driving your arms behind you during the downward phase (illustrated), (2) driving your arms forward or upward (illustrated) during the jumping phase, (3) driving your knees towards your chest (illustrated) during the jumping phase., or (4) increasing the height of the raised platform or box.