Quote Originally Posted by emily_in_nc View Post
1. Exercise-induced asthma?
2. Muscularity (a bit difference than being "out of shape", which I would consider more of an endurance thing).
3. Power to weight ratio.
4. Heart problems (hopefully not!)

I'm similar to you -- I've been a semi-fast rider in the past when I was riding a LOT, but I have never been a fast runner at all. I am a fairly fast hiker, but nothing spectacular. I have EIA, am not all that muscular, and am very small (102 lbs). I get passed by larger, more muscular female riders on my mountain bike fairly often, which I think is can be an example of #3.

Emily
Well, maybe my issue is just due to not being very muscular as well (5'2" and 105 lbs)--I don't have asthma, and definitely no heart problems (thank goodness!!). Actually, next week I am participating as a healthy control in a research study that involves a VO2max test and body composition analysis in the screening visit, so maybe that will shed some light on the situation. Should be interesting at least.