A recumbent bicycle differs from a standard, stationary bicycle and elliptical machine primarily in how you position yourself on the device. With an elliptical machine, you stand. On a standard bicycle, you sit upright or stand on the pedals.  With a recumbent bike you are, of course, recumbent, with a backrest supporting your spine. This low-slung, seated position makes recumbent bicycles “beneficial for people with back pain or balance problems,” said Kathy Dieringer, a board member of the National Athletic Trainers’ Association and president of D&D Sports Med in Denton, Tex. “You really can’t fall off.”  Riding a recumbent bicycle also may strengthen the hamstring muscles more effectively than using an upright bicycle. In a 2014 study, researchers found that novice cyclists activated their hamstrings with more force while pedaling a recumbent than a standard stationary bicycle.  On the downside, recumbents generally engage fewer muscles over all than either upright bicycles or elliptical machines, Dr. Dieringer said. An upright bicycle or elliptical will engage and strengthen muscles in your abdomen, buttocks, lower back, shoulders, neck and arms that are quiet while riding a recumbent.  So a moderate workout on a recumbent generally burns fewer calories per minute than using either of the other machines.  That differential grows if, like many people, including me, you take advantage of the recumbent machine’s lulling, gentle posture to read, watch television or otherwise loaf while pedaling, achieving only a light exercise intensity.  Over all, “I advise people who do not have balance problems and are familiar with the equipment to use the elliptical machine,” since it exercises so many muscles, Dr. Dieringer said. “And avid cyclists obviously should use the upright bicycle,” since it simulates riding outdoors far better than the recumbent.  “But for someone who’s a novice” at the gym, she said, “or who has back pain or any issues with balance, the recumbent is a good choice.” Although — and this is advice I seldom give — you might not want to read.
Readers ask: How does a workout on a recumbent bike compare to one on a vertical bike or elliptical machine?