In addition to the injury factor (especially your joints), if you don't give your muscles adequate recovery time, you can actually set yourself back - even to the point of losing muscle mass. Working different muscle groups on different days actually optimizes the development of new muscle. You'll have stronger, more energized workouts, too. Most of the aerobics instructors at my club rotate their workouts, and even at that many (at least the ones I've chatted with) are nursing some injury due to the repetitious nature of their work. These instructors probably can get away with teaching the same classes over and over because they're not testing their limits during each workout. Anyways, I bet if you were to talk to some of your instructors they'd recommend that you mix it up, too.
180 (Size 18+)/140 (Size 8/10)
Last edited by Rupertsmom; 07-02-2002 at 10:32 PM.