post a vid.
most likely letting go too early, having a stiff arm (since loose arm should just drop after you let go w/ left, and also you're probably hitting the ball using all arm instead of hitting w/ the body. you take it back far because you're not hitting w/ the body so that's the only way you get power by giving the racquet a long path to travel. booo!!!
Yonex VCore 100s - SW 351 6pts HL Tour Bite / Luxilon 4G 16 @ 51lbs