Hi,These machines help a person work-out both the upper and the lower body at the same time. For instance, you can exercise your arms and upper body muscles by taking advantage of the handles or poles, and also your quadriceps, calf muscles, hamstrings or gluteals by working the pedals. As the pedals that drive the moderately heavy flywheel of the machine has a two-way crank, you can pedal in a reverse direction too. This stirs up a whole new range of lower body muscles. This is particularly helpful for those who have to sit tight at one place for hours together.