I agree with Indysteel. Make sure you are balancing your workouts. I spin twice a week with a day in between. The other days I do strength training, yoga, swimming and other cardio. Alternating my upper and lower body workout days is what my trainer has me do. I also get my bike out and ride on days I can. More so in the warm months, of course. And even then, I was told to up my miles no more than 10% a week AND cut back by half on bike miles every four weeks to give my body a rest. What spin class HAVE allowed me to do, is to jump into higher outdoor miles once milder weather hits. This is a definite plus.