[danny_shank]

I think it also depends on your swinging pattern. I had back problems at 15 years old due to the craze of fixing the right knee, having very minimal hip turn and a large shoulder turn and then spinning the hips very fast on the downswing. Very hard on the back.

Now i let the right leg straighten, the right hip turn out the way and allow the left knee and foot to be naturally pulled across. I combine this with a free armswing and i still have power but i'm not putting nearly as much strain on my body.