Are these out of the saddle sprints or seated? Do they provide you with an RPM? Do you have enough resistance on the flywheel?
A full max sprint is only good for a few seconds. Dangerous on a spinning bike if you don't know where the brake is and have on enough resistance. I would say 150 to maybe 220 RPM, some track sprinters can do that. For many 120 is max. If you go with little resistance once you slow the 40lb flywheel can really hurt you, ankle, Achilles, knees, or the foot can come out and you will get nailed by the free spinning pedals. Know where the brake is and use it.
This also depends on position, form, experience, etc. If you can do 120 rpm for a minutes that is good. 150 is awesome with some resistance and no bouncing. Do what you can without bouncing. If you feel you are out of your envelope make a modification and back off. Do 10 sec on and 10 off.
Remember the class is about you! Protect you.
I can't comment on the instructor unless I was in the class and got the entire picture. Some are there teach, guide, and looking out for you and others are there to say, "look at me".
| current weight: 192.0