Last month I was training in the evening. After compleating one of the best forms I ever felt. I was playing with flying butterfly kicks. Landed hard and felt the knee (right) hurt. and not let me put any weight on it sending me to the cement. Yes I tryed to roll but the cement was really fast! Laying on the ground i thought it was over. Well after personal rehab. (R.I.C.E.) It is back in order. Kindof scared me. So at 50 years old I may re think the moves again and start riding my bike more. (no more flying stuff) Be well. Shawnzai!