Outside Magazine, February 1995
Running six miles is easier on a treadmill than in the real world of wind, unforgiving pavement, traffic lights, and dogs. So if bouts of nasty weather move some of your training for a spring marathon inside, you're going to have to tweak your routine to get a valuable workout.
"You can certainly supplement your outdoor training with work on a treadmill, but I wouldn't plan to run all winter inside and then try to run a race," says William G. Herbert, an exercise physiologist at Virginia Polytechnic. "On a treadmill you're not really hauling your weight forward or facing resistance from the environment, so you lose some training effect." You can make up for that loss, Herbert says, by increasing the machine's incline until you're working at the same heart rate as outdoors. According to Herbert, if you typically run on flat land, you'll need to set the treadmill at a 2 to 4 percent grade. If you run on hilly terrain, you'll have to experiment, using your heart rate as a guide.
While varied terrain might be exactly what makes your outdoor running enjoyable, the absence of distractions inside has its own appeal: The predictability of a treadmill can actually be its biggest advantage. "Without environmental variances, it's easy to set a pace and really concentrate on your breathing and technique," says Rick Howard, an exercise physiologist and personal trainer in Philadelphia. "A treadmill forces you to run at a constant speed, so you get to know how a steady seven-miles-per-hour pace should feel when you're training on the streets again."
In addition to using a treadmill to hone your technique, Howard suggests doing interval training once or twice a week. Run for two to three minutes at 80 to 85 percent of your maximum heart rate; then slow down until you're at 60 to 65 percent and maintain that pace for two to three minutes. Alternate between the two levels of effort for 30 to 40 minutes.
You can also use the treadmill in an unconventional way to strengthen quads and calves, a runner's notoriously underdeveloped muscle groups. "Set the treadmill at a slow speed -- 1.7 to two miles an hour -- and walk backward for a five- or ten-minute warm-up before you get going in the usual direction," suggests Howard. They might give you funny looks at the gym, but at least you won't back yourself into a pothole.