Originally Posted by
Sunsanvil
You may have hit it on the nose. When I went to the LSB about it last year thinking it was a frame-size issue, they put me on the trainer, took pics, and said that it was just a posture issue, that I needed to roll my pelvis forward. I tried to do that for the later half of last summer but it was unnatural, or at least my muscles didn't want to go there.
That's interesting, and sounds right. Probably a combination of (relatively) weakish core strength and perhaps some flexibility issues -- both can be worked on, in my experience, in a pretty non-aggressive way. Perhaps consult a good (sports) physiotherapist? Are there any good sports medicine clinics in your area? Only takes two or three sessions to get the right set of routines to follow.