Start by bracing your abdominals.
Tuck your elbows in at your sides and position your feet slightly apart.
Inhale. Push down until your elbows are fully extended but not yet in the straight, locked position. Keep your elbows close to your body and bend your knees slightly on the pushdown. Resist bending forward. Try to keep your back as straight as possible as you push down.
As you exhale, return to the starting point using a controlled movement.