I have run a half marathon, two full marathons, and even an extreme trail ultramarathon. But what separates me from most other marathon runners, is that except for a rare run outside, all my training has been on a treadmill. Most other runners I know hate the treadmill, and sometimes refer to it as the dreadmill. But the treadmill has some advantages over running outside. Of course, there are also some disadvantages as well.
One of the biggest advantages of a treadmill is the ability to run day or night regardless of the weather. Where I live, it gets brutally cold in the winter, and uncomfortably hot and humid in the summer. But with a treadmill, I am able to train year round.
Another advantage with a treadmill is the ability to run at a specific pace. Most marathon schedules call for running at various paces on various days. Outside it is near impossible to know what pace you are running while you are running. You can run on a track, and look at your watch as you pass certain markings to learn what pace you have already run. And depending on the terrain, it may difficult, if not impossible to maintain a consistent pace. But if my running schedule says run 10 miles at a 10:00 pace, I can just set the treadmill to 6mph, and run 10 miles at exactly a 10:00 minute per mile pace.
The biggest disadvantage of running on a treadmill is the monotony. Most people get bored running on a treadmill for hours. I have a TV set up in front of mine, and will watch movies, or whatever is on TV.
Another disadvantage of long distance running on a treadmill is the potential for distractions. It is too easy to go take a bathroom break, get lunch, or check email. This is one of my biggest problems. I will take breaks during long runs to take care of the distractions. As long as I run all the miles, I have generally been okay in the end. But with willpower, this problem can be overcome.
Another minor inconvenience of training on a treadmill is that you are not cooled by the passing air as your run. I solved this by placing a small fan on the floor in front of the treadmill that blows air onto me to help keep me cool.
While training on the treadmill for my first road race, a half marathon, I was nervous about whether the road would be significantly harder than running on the treadmill. I did a couple training runs out on the road to see how it would feel. I was surprised to notice little difference in the impact, and found that I actually ran faster on the road than I was expecting to.
I was also concerned about the lack of hills on a treadmill. In my earlier treadmill training, I would set the incline to 3 or 4. I had read somewhere that this would simulate the road better. But I was also not able to run as fast. So at times I would set the incline to the lowest setting, and would do faster runs. As time went on, I just left the incline on the lowest setting, and run faster. I have not found this to limit my running. Most marathons are relatively flat anyway, with only a few small hills.
I was also worried that since I was not actually propelling my body forward like I would be when actually running on the road, that running on a treadmill was actually easier than running outside. This has turned out not to be an issue. When I have run outside in races, I have actually tended to run faster and easier than I have on the treadmill.
MARATHON BLOG