Pros

• You never have to worry about the weather or time of day. Whether it's raining, snowing, blazing hot, or icy, you don't care because you don't have to run outside. You have the pleasure of running in a temperature controlled environment. You can run in any season, at any time of day. If you're a woman, you may worry about being attacked if you run outside at night. With a treadmill, that worry is gone. You're safe and sound inside. If you like running in the early hours of the morning, but hate running in the dark, you don't have to worry about it with a treadmill- it's never dark with a treadmill. So basically, a treadmill gives you freedom of choosing when you would like to run, regardless of external conditions.


• Treadmills are also great if you want to measure your vitals . Yes, you can buy a hand-held heart monitor, but they can be a pain to lug around with you. With a treadmill, all the equipment is right there at your finger tips. All you have to do is attach the heart monitor to your finger or ear (or wherever it measures from) and you're good to go.


• Treadmills allow you to vary your programs. True, when running outdoors you may be able to find varying landscapes that will offer challenges of their own. But on a treadmill you can vary your incline and difficulty every few minutes or few miles. You could do steady jog at 10% elevation for 1 mile, then 4% elevation for 3 miles, then sprint at 8% elevation for .5 miles, etc. You can also choose from a wide variety of running "routines" that will help build strength or endurance, depending on what you'd like to focus on that day. Or you can do a mixture of both.


• If you have a treadmill inside your home, you have no monthly fees or people waiting to use the machine. You can also watch TV or movies while you workout.

Cons

• Treadmills can never simulate a road workout perfectly. They may allow varying courses, speeds and inclines, but they can never prepare you for road surfaces like gravel, sand, cement and dirt.


• By nature of being indoors, treadmills are easier to run on because you don't have wind or other weather resistance. This can give you a false sense of how fast you can run indoors.


• If you own your treadmill you have to maintain the machine and that may be costly. To top it off, it may lead to lost training days. If you are in your home, you may also have to deal with family issues, ringing phones and delivery people at your door. Plus, you have to be self-motivated throughout the whole workout because there are no other people working out beside you for inspiration, and no trainer shouting at you to keep up the good work.


• If you don't own your treadmill, but use one at a gym, it can be expensive to pay the monthly fees. You also have to travel to get the gym.


• When running on roads, you are constantly adapting to surface changes, even if it seems completely flat. Therefore your pace is varying constantly. These factors give you the opportunity to work out different muscle fibers in slightly different patterns. On the treadmill, you call upon the same muscle fibers over and over (if you maintain the same speed and incline).