Originally Posted by
Biscayne05
If you're the type that does 50km-100km each time, you're bound to burn muscle...so that argument isn't really going to cut it with hardcore riders.
Cardio at an optimal level is 30-40mins (5k).
Correct me if I'm wrong but, doesn't the body use glycogen from the liver for energy during aerobic exercise (muscle glycogen for anaerobic exercise)? And once you run out of glycogen from your liver, your body starts converting fat to use for energy?
And only after running completely out of all the possible fat your body would start destroying muscle for energy?
50-100 km is nothing. People do that regularly on a daily basis and don't "burn muscle".