[dude]

Is a Two-Mile Run Worth the Bother?

In reading yesterday’s post, Alan was struck by the presence of a couple of two-mile morning runs in the sample week’s training that I shared. In a comment on the post, he asked me, in so many words, “Is a two-mile run really worth the bother?” It’s an interesting enough question to me to merit answering here on this website’s main stage.

The notion that very short workouts are not worth the bother for competitive endurance athletes is venerable and widespread. You hear cyclists say that if they don’t have time to ride at least 20 miles they just leave their bike in the garage, as 15 miles are as good as nothing for one who rides 200 miles a week or more. Runners routinely raise their eyebrows at my practice of running as little as two miles or even a single mile in the morning. Triathlon coach Phil Maffetone opined in one of his books that an aerobic workout must last at least 20 minutes to be of any benefit.

The prejudice against very short workouts is rooted in a blinkered view of exercise physiology in which metabolism is everything and the nervous system is nothing. Since the very birth of sport science nearly a century ago, exercise physiologists have been nearly blind to the fact that, in addition to a challenge to the body’s capacity to supply fuel and oxygen to the muscles, which stimulates improvements in this capacity during the recovery period between workouts, endurance training is also movement practice that improves movement efficiency instantaneously, within workouts. Every stride you take–whether it’s within a 20-mile-run or a two-mile run–counts equally as practice of the running stride and contributes equally to improvements in stride efficiency. As I point out in Brain Training for Runners, on one level running is no different from juggling. A juggler certainly would not consider a practice session that did not last long enough to make him tired “not worth the bother”, because he knows the point of juggling practice is to improve coordination, not endurance. While building endurance certainly is one major purpose of run training, improving coordination is another major purpose that short runs serve as well as long ones.

But I believe that very short runs can contribute to the development of other aspects of running fitness as well. In endurance training, chronic training stimulus is more important than acute training stimulus. In short, training frequently and in high volume is more important than training very hard in individual sessions, which is also important, but less so. In this regard, endurance training is very different from strength training, in which it pays to train very hard in nearly every session.

Very short workouts represent a way to meaningfully increase chronic training stimulus without greatly increasing the risk of overtraining and injury in the runner who is already doing close to the maximum amount of training he can handle without the presence of very short workouts to his regimen. In any given week, very short runs add as much as 10 miles to the chronic training stimulus that is my week’s training and thus account for as much as roughly 15 percent of my training. That is significant.

You can only get so fit without regularly performing longer, harder workouts, but the total volume of training trumps the magnitude of the hardest individual workouts in terms of impact on fitness development. An 80-mile week with seven 10-mile runs and five two-mile runs is every bit as good as an 80-mile week with seven 11.3-mile runs.

Indeed, in some respects the former might be even better, because the training will be more easily absorbed. I’m pretty sure that I would be carrying around more fatigue and soreness from day to day if I eliminated my short morning runs and tried to cram those few miles into my existing afternoon sessions.

http://mattfitzgerald.org/blog/?p=211