The overhead squat is the ultimate core exercise, the heart of the snatch, and peerless in developing effective athletic movement. This functional gem trains for efficient transfer of energy from large to small body parts - the essence of sport movement. For this reason it is an indispensable tool for developing speed and power. The overhead squat also demands and develops functional flexibility, and similarly develops the squat by amplifying and cruelly punishing faults in squat posture, movement, and stability.
The overhead squat is to midline control, stability, and balance what the clean and snatch are to power - unsurpassed.
Ironically, the overhead squat is exceedingly simple yet universally nettlesome for beginners. There are three common obstacles to learning the overhead squat. The first is the scarcity of skilled instruction - outside of the Olympic lifting community most instruction on the overhead squat is laughably horribly, wrong - dead wrong.
The second is a weak squat - you need to have a rock-solid squat to learn the overhead squat. We strongly recommend you review the December 2002 issue of the CrossFit Journal on squatting before attempting the overhead squat; you could save yourself a lot of time in the long run. The third obstacle is starting with too much weight - you haven't a snowball's chance in hell of learning the overhead squat with a bar. You'll need to use a length of dowel or plastic PVC pipe; use anything over five pounds to learn this move and your overhead squat will be stillborn.