A recumbent bike is a cardiovascular machine that gives you a similar workout to a regular exercise bike. The difference is with the way the bike is set up. On a recumbent bike, there is a bucket seat with a backrest. The pedals are out in front of you, so when you operate the machine, you are in a horizontal position. This can take pressure off your lower back and prevent you from slouching. Even though the bike is a piece of aerobic equipment, there are multiple muscles that you will work when you use one.