Basics

• A treadmill turns a belt with a motor, creating a moving surface to walk or run on. An elliptical uses rotating foot petals that move in an elliptical pattern to emulate walking or running. Both machine types feature different settings from easy to more strenuous workouts.
  
  

Health Benefits

• Consistent use of either machine will increase cardio strength, endurance, bone density and core leg strength. Many treadmills include a feature to increase the incline, which let you target certain leg muscles. While the handles on an elliptical let you work your upper and lower body at once, burning calories more efficiently.
  
  

Impact

• Running on a hard surface such as concrete can cause impact stress on the joints, which can cause injury. A treadmill offers a low-impact cardio exercise, but because the feet still hit the treadmill, there is impact. An elliptical, however, has no impact, and is easy on people with joint problems, such as stiff knees.