Sorry for taking so long to answer your question Nicole! But hopefully this will be the info you are looking for… I’ve actually had other people ask me about spinning classes and biking in general making your legs get bigger. BUT this is not true. If anything spinning will help to tone up those legs and slim you down. They may feel more muscular because they are getting stronger, but when women tone up they actually lose inches unlike men who gain muscle and increase in size. Spinning bikes don’t provide enough resistance to result in the fatigue and overload that is needed to build muscle like strength training does. If that were the case, you'd only be able to pedal against it for a few seconds tops, not a full hour. Spinning is a great way to get that cardio work in while sculpting those calves and thighs at the same time. Keep it up!!