Have you ever wondered why your standard “jogging” pace is what it is?
Every runner has a natural running pace. It’s the pace you fall into automatically when you go for your typical moderate, steady run of a certain predetermined distance or duration — five miles, 45 minutes or whatever (a format that probably accounts for 90 percent of all runs performed daily by the worldwide population of runners).
For each runner this pace changes over time as fitness is gained or lost, and it even changes from day to day based on how one feels — a factor that is influenced by fatigue from preceding training, above all.
What determines a runner’s natural running pace? Exercise scientists have made few efforts to answer this question, and the few answers that have been proposed are unsatisfactory. In a 2001 study, researchers from the University of Udine, Italy, tested the hypothesis that natural running pace is determined by the blood lactate level. They expected to find that natural running pace would correspond to the maximal lactate steady state, or the fastest pace a runner could sustain without lactate accumulating to a concentration that would cause fatigue.
Eight recreational runners were first tested for their lactate threshold speed and heart rate, and were then asked to run for one hour at their natural pace. On average, the runners completed the one-hour run at approximately their maximal lactate steady state; however, while there was a lot of variation in the individual lactate steady state speeds among the eight subjects (some were much faster than others, for example), there was significantly less variation in pace levels maintained in the one-hour run, a finding that led the study’s authors to conclude that “besides the need of avoiding lactate accumulation in blood, other factors must be involved in the choice of speed in running.”
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There were two problems with the University of Udine researchers’ lactate-based hypothesis. First, there is no evidence that running pace is strictly limited by blood lactate levels. In short races, for example, runners routinely achieve blood lactate levels that exceed the lactate threshold value. If such high lactate concentrations are “allowed” in short races, how could they impose an immovable ceiling on running pace in other circumstances? The second problem with the lactate hypothesis is that there is no mechanism whereby blood lactate could regulate running pace even if it did cause muscle fatigue. If blood lactate did regulate running pace throughout exercise prior to fatigue, then each runner would run the same pace in every run — the pace corresponding to the “right” blood lactate level.
What the University of Udine researchers were forgetting, and what almost all exercise physiologists forgot in all of their work until sometime after 2001, was the role of the brain in exercise regulation. It is the brain that tells the muscles how hard to work — in this case, how fast to run — during all exercise situations. Therefore, the true explanation of the natural running pace phenomenon must be seated in the brain.
This truth was suggested by another 2001 study — this one performed by researchers at Wayne State University in Wayne, Nebraska. Eighteen men and women were asked to complete 20-minute workouts at their individual preferred intensity level in three separate modalities: treadmill running, stationary cycling and stair stepping. The physiological variables were all over the place in the three workouts. On average, the subjects completed the cycling workout at a much higher percentage of VO2max than the treadmill and stair stepper workouts, and completed the stair stepper workout at a much higher percentage of their maximal heart rate than the cycling and treadmill workouts.
However, their ratings of perceived exertion were almost exactly the same in all three workouts. Clearly, then, natural running pace and preferred intensity in other forms of exercise are not totally determined by physiology but are instead selected by feel. And where does feeling happen? In the brain.
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Other studies have produced similar results. When given the freedom to go by feel, exercisers consistently choose an exercise intensity that is toward the high end of the comfortable range in relation to the duration of the workout they are trying to complete. Why this particular level of exertion? I believe it represents a compromise between two competing desires that the brain manifests in every exercise session: the desire to complete the task as quickly as possible (in other words, to get the workout over with) and the desire to feel comfortable. So your natural running pace — whether it’s 9 minutes per mile, 7:30 per mile, or 6:15 per mile — represents the running-specific version of this compromise relative to your individual running ability.
But is your natural running pace a good thing or a bad thing with respect to your goal of increasing your running performance level? After all, the mere fact that it is natural does not necessarily make it an effective means to the competitive ends you seek as a runner.
Well, it so happens that natural running pace corresponds closely to the running intensity associated with the maximal rate of fat burning, making this pace ideal for longer runs designed to increase fat burning capacity and raw endurance. And because natural running pace does not tax the body as much as faster paces, it is possible to maintain a greater overall volume of running when most of your running is done at this pace, and the more you run, the more your running economy improves.
So your natural running pace does have a place in your training. However, runners commonly do too much of their running (in many cases all of their running) at their natural running pace. At least one of your weekly runs should include a dose of running at higher intensity levels, which yield fitness benefits that complement those produced by running at your natural running pace. These faster runs don’t always have to be grueling interval sessions and lactate threshold runs. You can also modify your steady-state runs at your natural running pace to incorporate a modest amount of faster running.
For example, in a fartlek run you sprinkle a handful of short, fast bursts (6 x 45 seconds at 5K race pace, for example) into an otherwise steady, moderate run to develop a little speed and supra-threshold fatigue resistance. Fartlek runs work well in the base phase of training, when you are not yet ready for those grueling interval sessions.
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Progression runs are steady, moderate runs with a segment of faster running (typically 1-3 miles at marathon to half-marathon race pace) tacked onto the end. These runs also work well in the base phase, when you are not yet ready for grueling threshold runs, as well as anytime in the training cycle when you feel especially good on a planned “easy day” and want to take advantage of the opportunity to subject your body to a greater training stimulus without going overboard. Finally, progression runs work well as modified long runs in the peak phase of training, when you want to transform the raw endurance you have developed with long, slow runs into race-specific endurance.
Aside from knowing when and when not to use your natural running pace, it is also helpful to simply monitor it. Indeed, tracking changes in your natural running pace is one of the simplest and most motivating ways to monitor your running fitness level. As the training cycle progresses, you should see this pace gradually come down. That is, you will run faster and faster at the same, high-end-of-comfortable exertion level. Just go by feel and let it happen.
About The Author:
Matt Fitzgerald is the author of numerous books, including Racing Weight: How To Get Lean For Peak Performance (VeloPress, 2012). He is also a Training Intelligence Specialist for PEAR Sports. To learn more about Matt visit www.mattfitzgerald.org.