Running offers one of the best overall workouts. But it does have its drawbacks. Temperature and weather extremes can make it hard to stick to your training plan. The exercise machine industry has filled this need by creating many types of indoor running machines. The most popular one continues to be the treadmill. Here are three reasons why:

• Convenience —Most people don't want to run outside when it is cold, hot, stormy, or dark. Even people who have access to an indoor track or health club can find it hard to make time to get there. A home treadmill allows you to exercise more often. You can even watch your favorite TV show while running.
• Physical benefits —Using a treadmill is great for the heart, lungs, and bloodflow. It is an easy way to lose body fat, strengthen muscles and bones, and ease stress.
• Low-impact workouts —Years of walking or running on hard surfaces can take its toll on feet, legs, and hips. Treadmills can ease this stress.

Motorized vs. Non-motorized Treadmills

When buying a treadmill the biggest decision is whether to get one that is motorized or a non-motorized. A motorized treadmill is large and requires you to keep pace as the machine's motor moves the treadbelt at your selected speed. A non-motorized treadmill is compact and requires you to push the belt with your feet, so you will only go as fast as you can push.

There are other differences, too. Most non-motorized treadmills are under $200. High quality motorized ones range from $1,000 to $9,000. It depends on the features you want. There are models under $500, but you'll need to make sure they are safe and will last.

Non-motorized treadmills help you burn calories more efficiently, since you supply the muscle power to move the treadbelt. But this means you'll also move slower and get tired more easily unless you are in good shape. This may mean you burn fewer calories. These models also have other drawbacks. They need to be tilted on an incline in order to use them. This can make running hard if you are out of shape or not used to running. Finally, you will push harder on one leg as you get tired. This can make the motion of the treadmill choppy and harder to run on.

Making a Choice

It is usually better to buy a motorized treadmill unless you are in good shape. People who choose to buy a motorized model should consider these features:

• AC or DC motor —AC motors are noisier. They also drain more power and need a dedicated power source.
• Horsepower —Runners will need a motor with 3 horsepower or higher. If you walk, you can consider a lower number. Keep in mind that you are buying something that you want to last.
• Belt thickness —2-ply belts are stronger and curl less around the edges.
• Running surface length —A longer running deck will allow for a more natural stride and easier running motion.
• Speeds —If you plan to walk on your treadmill, 0.5 mph minimum to 6 mph maximum speed should be enough. If you plan to run, 0.5 mph minimum to 8 to 12 mph is better.
• Shock absorption —Manufacturers use different methods to absorb the shock to your feet and legs. They often use thicker running belts and thinner running decks. Some use actual shock absorbers placed under the deck (more expensive). Still others use "floating beds" where the treadmill floats on special springs (more expensive still). You'll have less wear and tear on your body when you chose a machine with a high level of shock absorption.
• Incline —Treadmill inclines vary from 2% maximum to as much as 15% to 25% maximum. The greater the incline, the more varied a workout the machine can offer. You'll also want to check the machine's incline mechanism. Electronic switch inclines are better than manually operated inclines. Automatic inclines that change during your workout can be nice, but expensive.
• Electronic feedback —Almost all motorized treadmills have speed, time, and distance displays. Most also include preset or customized workout programs. Your choices are limited by your wallet. Expensive models can store personalized programs and records of your workouts. Many machines also offer heart rate monitors and monitors that set off an alarm when you get outside your target heart rate. Be careful, though. These monitors are not always accurate. Chest strap monitors are likely to be the most accurate.

You've read about all the options. Here are three points to consider. First, try to buy a machine that includes a free trial period. If not, make sure there is a return policy. Be sure to understand the warranty. Second, think about buying a used treadmill. Check your local want ads. Local health clubs may also have some when they upgrade to better machines. Lastly, you should always talk to your doctor before you begin any new exercise program.