A cross-trainer or elliptical is a gym equipment that has low impacts on the joints yet simulates walking, running, and climbing. The whole body gets in the act, but much-reduced force is applied to the joints. Likewise, an indoor bike is designed for stationary cycling. It might well be referred to as a spin bike or upright bike, as they offer wonderful cycling workouts as far as cardio and muscle toning and strength building. The resistance can be adjusted easily depending on preference.