When runners compare treadmill running to outdoor running, they tend to focus on the limitations of the former. It’s true that there are many things you can do outdoors that you can’t do on (most) treadmills: sprint, run steeply downhill, vary your surfaces, enjoy the scenery. But there are also some things you can do on the treadmill that are difficult or impossible to do outside, such as precisely adjust speed and incline. By exploiting these capabilities, you can create and execute some fun and effective treadmill-specific workouts to help get through the winter.
Among these is the ascending tempo run. As the name suggests, this workout puts an uphill twist on the traditional tempo run, which entails running for a moderately prolonged period—usually at least 15 minutes—at or near lactate threshold intensity, which in the typical runner is the fastest pace that can be sustained for about 60 minutes. Obviously, when you’re running uphill, you can’t go as fast, and the steeper the hill, the more you must slow down to remain at a speed that you can hold for an hour.
The specific numbers are determined by physics. Any given speed of running on a 0 percent incline has a precise equivalent at a 2 percent incline, a 4 percent incline, and so forth. The ascending tempo run uses these known relationships and the treadmill’s capabilities to make threshold-pace training a little less monotonous than it often is. Like a traditional tempo run, the ascending tempo run cultivates the ability to run efficiently and comfortably at moderate aggressive speeds, but because it involves working against gravity, it adds a strength-building dimension, and running uphill reduces impact forces.
Before you try this workout, you need to do a little math. The first step is to determine your lactate threshold pace, which is the fastest pace you could sustain for one hour in a race. For most runners, this number falls somewhere between 10K pace and half-marathon pace. If you have raced at these distances or you can confidently estimate the times you would achieve in a 10K and a half marathon today, use these data points, placing your LT pace proportionally closer to whichever race time is closer to one hour.
If you lack such data, try the following test: Warm up thoroughly and then accelerate to a pace you feel you could sustain for 60 minutes and no longer. Fine-tune your speed until you’re sure of it and then note your pace. Studies have shown that athletes are generally pretty good at estimating their time limit at different speeds.
The next step is to convert your LT pace (minutes and seconds per mile) into speed (miles per hour), which any of a number of online calculators can help you do if you don’t know how. For example, if your LT pace is 7:30 per mile, your LT speed is 8.0 mph. Now you’re ready for the ascending tempo run.
Warm up with 10 to 20 minutes of easy jogging with the treadmill set at a 0 percent incline and the speed set 1 to 2 mph slower than your LT speed. (Why not a 1 percent incline, in keeping with the notion that treadmill running is “easier” than outdoor running? Because this notion is fallacious!)
After completing your warm-up, accelerate to your LT speed without adjusting the incline for now. Maintain these settings for 3 minutes and then raise the incline to 1 percent while simultaneously slowing down by 0.3 mph. This combination of adjustments will balance out to keep you at or near LT intensity. Continue for 3 more minutes and then raise the incline to 2 percent while slowing down by another 0.3 mph.
Repeat this process of raising the incline and slowing down until your total time at LT intensity is between 15 and 30 minutes, depending on your fitness level, then return to the original settings and cool down for 5 to 10 minutes. Note that if you do a longer version of this workout and your LT speed isn’t especially fast, you may find yourself walking in the last segment or two, which is fine.
Try adding one extra 3-minute segment each time you do the ascending tempo run, and be sure to adjust your starting speed as you get fitter and your LT pace improves.