For those who either can’t or don’t want to use the treadmill, the exercise bike or the stationary bike is a great alternative. Your body is supported, and there is much less impact on the joints.
Just as with the treadmill, you want to vary your workouts on the bike. Some days just ride easy, other days do short intervals and long tempos, and throw a hill workout in every now and again as well.
There are two basic types of bikes in the gym; upright and recumbent. The upright bike has you more vertical, while the recumbent bike positions your body more horizontally. The benefit of the recumbent bike is that it supports your back and can be a little more comfortable than an upright.
The downside is that you have to work harder to get your heart rate up on the recumbent bike. So if your goal is to burn the maximum number of calories, choose the upright bike.