Tae Bo is a great workout, and Billy Blanks is a great motivator and trainer.

Unlike most exercise tape trainers, he actually tells you when to check your form to be sure that you are not hyperextending your knees and elbows when you kick and punch

(VERY important ... never "lock out" your knees when you kick, or your elbows when you punch ... that is, never extend them all the way out. Remember, when you are actually punching or kicking something/someone they will be there stopping your momentum ... when you are punching and kicking air, you kind of have to do it ALMOST all the way out, but not quite. Does that make sense?)