My instructor will change my resistance sometimes but she knows me pretty well. She's very outspoken about not doing anything that'll cause injury but she also likes to push us. When she changes it, it is never by much and it's just enough to push me over the edge.

That all being said, I know she'd respect someone who didn't want her to do that. Also (like I said), she knows me. If I'm sick, recovering from a hard workout, or otherwise compromised, she leaves me alone. She is the most inspirational and interactive of all the spin instructors at this gym and her classes always have a waiting list.

My disclaimer would be each time you do something new, hold back a bit. You never know how your body's going to react to it