whoa, prestretching will not hurt your muscles, it may be an old idea but it won't hurt your muscles. I've taken martial arts for 39 years, and any dojo you go into will have you prestretch and no one has ever hurt muscles doing that. Professional sports like football have their guys prestretch as well. So no prestretching will not hurt you, it may not help you perform better on the bike, but it won't make you perform worse either.