Extension is when you increase the angle between two bones. Straightening your arms during your elliptical workout works strengthens the triceps -- the muscles on the back of your upper arms. You also work your shoulder, chest and back muscles in the upper body, and glutes, quadriceps and hamstrings in the lower body.

Cycling or spinning on a stationary bike at a vigorous intensity and cycling an elliptical machine are the best for burning the most calories. A 200-pound person will burn about 1,032 calories in a 60-minute spinning or elliptical workout. Using a treadmill for running can also be efficient.

You can get an effective aerobic workout with both an elliptical machine and a treadmill. However, elliptical machines might offer some advantages over treadmills. For example: Using an elliptical machine can be less stressful on your knees, hips and back than is running on a treadmill.