as a cyclist, i suggest you stay away from a spinning class. i sat in on one when i was on vacation. just to see what they were like. i informed the instructor i was not joining in on their workout, but i was just going to spin on my own in the back of the room..
the instructor, who was at best, a bad cyclist, had the out of shape non cyclists do only a warmup of a few minutes before hammering out some intervals... WTF kind of guidance is that? then when they were out of the saddle, they positioned their arms in a real funky way... a way that if you did this on the roads you would fall over for sure. very wierd class.
if you want cardio, and you like the inside spin classes of 45 minutes to 60 minutes, continue to spin, but i would do my own thing, after a longer warmup.as a former runner, and pretty close to age division american records, when i gave up running to take up cycling, i went to one of the bigger better bike shops and talked to the old old owner, and he told me to spin for a year.(outside on my road bike staying in an ez gear) he said you may have the lungs power from running 20 years, but for a year, spin at an ez-moderate pace in a small gear for a year before putting it in the big chainring. he said i have to develope my bike muscles.this was from a former national champ.
it takes a long time to develope. so sitting in on a class is fine but i would bag the intervals until you got your cycling muscles developed and you are use to the movement.
bike racing is very very hard. the last 1-2 hours of a race your legs feel like reps 8-10 on a set of 10 hard heavy squats.... but for 60-120 minutes.. after a few hours of hard racing..then the last 10k its just a sufferfest. dont let anybody tell you it isnt.
if your doing this for your cardio for bodybuilding, spin 90-110 rpm in a moderate gear. no intervals.
good luck spinning.
