Kneel down in front of a stable high surface such as a box.
Place your hands on the box shoulder width apart and lift your knees up.
You should have a straight line from your head to your heels.
Keeping a strong core and tightening your buttock muscles, bend your elbows, lowering your chest down towards the box.
Your whole body should move in a line.
Drive through the heels of your hands to straighten your arms out again.