Originally Posted by cyclintom

The problem with this is that the bodily composition of skeletal muscles (from memory) is something like 80% slow twitch muscles and the rest a mix. I have a lot of fast twitch in the remainder which made me a descent fighter but although I've been doing almost entirely climbing at relatively mild rates it doesn't seem to have changed the composition at all. Those rollers on many of my courses: I can barely improve my times by attacking them. But my overall time is actually a little better if I don't attack the rollers and ride over them normally. And in the group I ride with on the heavy climbs I find I can keep up with them if I do not try to go hard. But if I go harder I tire so rapidly that I actually lose time. So I do not believe that you can change your body muscle type composition as many resources tell us but are stuck as we were created.