Originally Posted by ls01

Shifting around is a sign of uncomfortability, but that doesnt mean your fit is bad or anything is wrong. When we go all out or even beyond, its normal to shift forward. You are familiar with the term , "on the rivet"?
I know when I am riding out of my class I have felt that way, not like something is wrong but more like something isn't right. I think it's just how our physicality *****es about being asked to do something that hard for an extended length of time. As far as feeling sick, you are doing it correct. I get that quite often under hard efforts. I have actually thrown up twice that I can recall on the bike because of it. I had just eaten and the ride leader decided it was breakaway time. I felt better afterwards, but never caught back up.