Manual Treadmills

• With a manual treadmill, a wide belt wraps around rollers built inside a deck. As you step on the treadmill, the weight of your body pressing down on the rollers provides the friction needed to move the rollers as you walk or run.
  
  

Motorized Treadmills

• With a motorized treadmill, an electricity-powered motor drives two rollers at opposite ends of the running deck. The motors turn the belt on which you run or walk. With the control panel on motorized treadmills, you can set variables such as the speed or duration for the motor, so you can make your workout more or less challenging.
  
  

Special Features

• While the simplicity of manual treadmills leaves them with essentially no features, motorized treadmills typically offer many features: You can change the incline, follow your heart rate and choose an exercise program.
  
  By pushing a button, you activate a motor that will either raise or lower the running deck to mimic running or walking on a grade. The heart rate monitor on a treadmill most likely has either a band that wraps around your chest, a plastic clip that goes on your finger, or a grip that you hold on to. Each of these has a sensor that measures your pulse for a set amount of time, then runs it through an algorithm to determine your heart rate.
  
  A treadmill also counts calories you burn during your workout. An programmed algorithm takes into account your weight, distance, effort and incline to determine how many calories you are burning. (However, these figures are notorious for being inaccurate, so read them as a general guide.)