There are two types of treadmills: manual and motorized. A manual treadmill is powered by your own two feet -- it's up to you to keep it going, and this can be a bit of a struggle, especially when it comes to maintaining a constant speed.
A motorized treadmill's continuous horsepower rating, or CHP, indicates the amount of power the motor will provide over the long haul. That's as opposed to peak performance horsepower (listed variously as HP, PHP, or THP), which indicates the maximum horsepower the machine can reach. The experts at Running Planet say a CHP of 1.5 is sufficient for a walking treadmill. Interval training, with its mix of inclines and speeds, puts more demands on the motor, so it requires a CHP of at least 2.0. The top-rated treadmills we found exceed those criteria. The Horizon Fitness T101 (starting at $599) and ProForm Performance 400 (starting at $599) boast a continuous rating of 2.25, and a jog should not strain the motors at all.
Running is possible on all the budget treadmills on our list, but the motors on some of them can't really accommodate serious runners. The Weslo Cadence (starting at $350), Merit Fitness 725T Plus (starting at $400), and the Gold's Gym GG480 (starting at $377) have peak performance horsepower of 2.25; however, the CHP latter two is 1.5 and the CHP of the Weslo treadmill is only 1.25, so these models really are walking treadmills. Using the peak performance power over long periods of time will burn the motor and cause friction on the belt.
Treadmill Warranty.The high demand put on treadmills can wear them out quickly if they're not made well. Because treadmills in our price range are built with less costly materials that are unlikely to last many years, experts say long warranties on the motor and parts are must-have features on a discount treadmill. The Horizon Fitness T101, ProForm Performance 400, and Merit 725T all have lifetime warranties on the frame, and the Horizon also has a lifetime warranty on the motor, which is exceptional for this price range. The ProForm comes with a 25-year warranty on the motor, the Gold's Gym GG480 is guaranteed for five years, and the motor on the Merit 725T is covered for two years. As for parts, the Horizon Fitness T101 and ProForm Performance 400 have one-year warranties. The Merit and Gold's Gym models are covered for 90 days. The Weslo Cadence G-40 has only a 90-day warranty for the whole thing, one reason we don't include it among our picks.
Treadmill Incline and Speed.One of the advantages of walking or running on a treadmill is the ability to stick to a set pace, a difficult feat on the ground. All of our picks have a top speed of 10 mph. Casual users are unlikely to want to go higher than that for anything other than a short sprint. The Horizon T101 also has a cool-down feature, which automatically slows the speed for four minutes.
Incline settings allow you to do interval training with a mix of hills and speeds. The Weslo Cadence G-40 has a manual incline, with three choices of grade. The other treadmills on our list have incline motors, with the ability to change the grade electronically from 0 percent to 10 percent. Preset workouts with interval training, available on all four of our picks, automatically change the incline during the course of the workout.
Treadmill Belt.Discount treadmills generally have one-ply belts, although the Horizon T101 has a two-ply belt. The dimensions of the belt should match your size and fitness goals. The experts at Running Planet suggest that for walking or interval training, a 54-inch belt is the minimum length to shoot for -- longer if you are tall. If you plan to do a good deal of running on a treadmill, the experts recommend at least 58 inches. The width of the belt should be at least 18 inches to accommodate some side-to-side motion, particularly if you are going to run.
For the most part, the cheaper the treadmill, the smaller the belt. The Horizon T101 and the ProForm Performance 400 both have belts that are 20 inches wide and 55 inches long. The Gold's Gym GG480 and Merit Fitness 725T are 18 inches wide. They are 50 and 45 inches long, respectively, which makes them fine for walking, but unless you're fairly short, running on them could be a problem. The same is true for the Weslo Cadence G-40, which has a very narrow belt, at 16 x 50. Some users who posted reviews on the Walmart website stress that the Weslo treadmill is meant only for walking; if you try to run, you are likely to bang your hands or arms on the grips.