This one might make you stick your booty out if you have poor core functionality and hip extension. It is a good test. Obviously, we do not jump like this all the time. The point is regardless of how silly you might look, once you achieve the positioning, it maximizes ankle and lower limb power. The limbs are forced straight, removing the anterior leg (quads) as the prime mover and placing the stress and muscular adaptation onto to the calves, Achilles tendon, and plantar facia. Weak ankles and tight calves are exposed, and if the shins tdo not remain stiff they will violently turn outward or inward. The movement improves hip extension and hip mechanics due to the aggressive force required by the posterior chain. They are great to throw in to quickly wake up the nervous system. They are used in preparing for cleans, and snatches as well as more difficult bouts of skills training and plyometrics. Try to master 4 sets of 4-6!