That opinion has undergone a gradual but dramatic change. First, I went from "never use" to a "necessary evil." Then to a "tool in the toolbox." Then, this past winter when it was cold and dark all the time, an "excellent safe way to run." And now, after yesterday's run, I see treadmills as a vital training tool, where I can get a unique workout that I can't get elsewhere.
Simply stated, their benefit lies in the fact that I manually, deliberately set the speed. And then, the treadmill, not my body, dictates the pace.
When I'm going outside for a run on asphalt, I'll wear my GPS watch and monitor my pace. I've noticed that, without thinking about it, as the miles tick off, I notice the minutes per mile creeping up as I get farther and farther into the workout. I can deliberately push the pace back to what it was in the first mile, but that's mentally taxing and difficult to sustain. As a result, my outdoor runs typically have a positive split.
On the other hand, when on a treadmill, I dial in the speed and the belt moves that fast whether my body wants to or not. In order to slow down, I have to make a deliberate mental decision, and turn the speed down manually. When doing so, I'm reluctant to turn it down too much, and also for not too long - effectively giving me a recovery period at a pretty fast pace. Also, I tend to have a negative split on the treadmill.
These benefits started to dawn on me this past spring when I was doing a lot of treadmill training, but I forgot about them as the weather started getting nice I shifted my attention to outdoor running to take advantage of it. Treadmill running became less and less prevalant, and as a result I can count on one hand the number of times I've run a 'mill between May and October. The outdoor runs were often on trails, and while they usually weren't easy, they *were* always very enjoyable.
And, perhaps not coincidentally, I noticed a dramatic and devastating speed decrease.
For the first time in months, I visited the gym last night for a treadmill run, mostly because it was getting late and I didn't feel like running in the dark. I started it at 5.5MPH, and added 0.1MPH every minute for ten minutes, so I was at 6.5MPH for a while. At 20:00, I was pretty tired, so I dialed the speed back to 6.0MPH and decided that it would be only for 5 minutes. It was hard but, at the end of 5 minutes of 6.0, I did feel better than the end of the previous 10 minutes at 6.5. What I did next was speed it back up to 6.5 again, and held that until I hit 30 minutes/3.1 miles (5K.) I was spent at this point. Then I did the treadmill-programmed cooldown, which at 3.5mph wasn't very pleasant for the first minute, but it backs off 0.5mph every minute for 5 minutes and I felt fully recovered by the end.
On the drive home, I reflected on the fact that -
* If I ran outside, the entire run would probably have been below 6MPH - maybe even below 5.5MPH.
* I don't feel like I can run a 30-minute 5K right now, but I did it on a treadmill
* I would have dealt with traffic, cold, and dark
* There definitely would not have been a thorough cool-down
* The only bright side was that, perhaps I would have gone longer - but overall, I wouldn't have gotten as good a workout.
The fast-paced recovery periods must be a critically effective tool in my experiment-of-one. I am no exercise physiologist, but I seem to remember something about "active recovery" that really forces the body to adapt to higher-intensity training, or at least faster running. This it also makes a lot of sense that if I force my body to recover at a somewhat intense pace before diaing in the speed again, then the body's natural recovery speed will adapt to that intense pace such that I can, if I want, run longer distances at that pace.
And, now that winter is nearly here, I think I'll be doing a lot more treadmill running anyway. For the first time in a while, I'm genuinely excited and hopeful about the direction of my training, and I have treadmills to thank for it.
Steve is taking a break from writing regular updates to his blog