Over the past ten months, I have written about scientific studies
on strength training, tapering, stretching, altitude training, and various
nutritional issues. I hope my articles have demonstrated that scientific
research can be used to optimize one's workout regimen and diet. However,
in trying to apply hard-core science to practical training issues, at least
two major problems arise.
The first problem is that endurance athletes ask very focused
questions for which there may not be any good data. "How long should my
tempo runs be?" is one example; it's a reasonable question, but the
scientific community doesn't have the answer, at least not yet. The second
problem is that, even when a particular issue has been studied, it
can be a royal pain to go look up the research and make sense of it all.
Thus, while a research-based approach to training can be very rewarding, it
can also be very frustrating, as one may devote hours to the pursuit of an
answer which may or may not exist.
Given these difficulties, you may ask, "Does this research-based
coaching advice have any sort of overall theme? Must each training-related
question be addressed with a separate trip to the library? Aren't there
any general principles which we can apply across the board?"
As it turns out, there is indeed an important "overall theme" which
emerges from the scientific literature on training: the principle of
specificity. According to this principle, when one trains one's body to do
a particular task, the body gets better at that task, but it doesn't
necessarily get better at other unrelated tasks. The improvement is
therefore said to be specific to the training task.
Bowling or lawn darts?
At first glance, the concept of specificity may seem rather
trivial. If a friend wanted to become a better bowler, we obviously
wouldn't advise him/her to play lawn darts or air hockey; we'd suggest that
he/she go bowling more often. Nonetheless, given the enthusiasm with which
some fitness gurus tout the benefits of cross-training, it's important to
remember that the best training for runners is, in fact, running.
For example, in the classic study of Pechar
et al. (Journal of Applied Physiology 36: 753-6,1974), a group of 20
male college students trained on treadmills three days per week for 20
minutes per day at 85% of their maximum heart rate. After eight weeks,
these subjects had increased their VO2max (maximal oxygen uptake, a measure
of endurance performance) on a treadmill by 6.8%. Meanwhile, a separate
group who underwent similar training on stationary bicycles only boosted
their treadmill VO2max by 2.6%. Thus, although cycling did improve
treadmilll performance somewhat, it was less effective as a training
stimulus than treadmill running.
These results might be surprising to some, given that both cycling
and running exercise the heart, lungs, and legs. However, as noted by Tanaka (Sports Medicine 18: 330-9, 1994), cycling and running stress the legs
in different ways; cycling places a heavy load on the quadriceps muscles,
whereas the plantar flexors (soleus and gastrocnemius muscles) are more
important for running. Thus, it makes sense that running performance
improves most in people whose legs are trained specifically for
The study described above is only one of many to examine the degree
to which training in one sport can improve performance in another sport.
These studies have been reviewed by Franklin
(Medicine and Science in Sports and Exercise 21: S141-8, 1989) and by
(Sports Medicine 18: 330-9, 1994); both conclude that, while fitness in
one sport can sometimes carry over to similar sports, there are also many
instances where cross-training does not enhance performance as much as
sport-specific training does.
By the way, I freely acknowledge that cross-training is
useful to runners who (a) are injured, (b) are susceptible to
running-related injuries, (c) want to spare their legs from too much
pavement-pounding, (d) have very weak muscles that aren't used in running,
and/or (e) need variety in their training to keep it fun. My point here is
simply that, if you want to do your best as a runner, you should emphasize
running in your training -- to the extent that your body and mind will
allow, of course.
In a study of movement speeds, Coyle
et al. (Journal of Applied Physiology 51: 1437-42, 1981) trained one
group of college men to perform fast knee extensions and a second group to
perform slow knee extensions. By the end of the study, the slow-trained
group had improved most in its ability to perform slow knee extensions,
whereas the fast-trained group had become superior at fast extension
Similarly, in a study of joint angles, Graves
et al. (Medicine and Science in Sports and Exercise 21: 84-9, 1989)
subjected one group of men to knee flexion training over a range of motion
of 0 to 60 degrees of flexion -- at 0 degrees, the leg is completely
straight -- while a second group trained over a range of 60 to 120 degrees.
As you might guess, the 0-to-60 group exhibited impressive strength gains
when tested with the knee joint positioned at between 0 and 60 degrees of
flexion, whereas the 60-to-120 training group improved its strength more on
the tests conducted at angles of 60 to 120 degrees.
Although these studies (and most others reviewed by Behm & Sale and
Morrissey et al.) concern strength training rather than aerobic endurance
training, they make a very important point about athletic training in
general. That point is as follows: if we want to get better at a
particular athletic task, it is not enough to exercise the muscles involved
in the task; we must use the muscles in a way that mimics the task itself.
For runners, in other words, it is not enough to run; in our running, we
must simulate the race we're training for. If we're preparing for a hilly
cross-country course, for instance, we should practice running uphill in
our training (Freund
et al., Medicine and Science in Sports and Exercise 18: 588-92,
Don't ignore the obvious!
Does all of this sound intuitively obvious? It should -- and yet I
think that a lot of us, myself included, don't always train as specifically
as we should. To cite an extreme example, the coach of a friend
discourages marathoners from doing long runs because he figures that going
the distance is simply a matter of mental toughness. Such advice directly
contradicts the principle of training specificity; if you expect to be on
your feet for three or four hours during the race, you should give your
body some practice at this task in advance of the race itself. And here's
another one: why do some people run endless sets of intervals at speeds
much faster than race pace without ever bothering to run at race
pace? Although the super-speedy workouts are no doubt useful, the
specificity principle suggests that training at race pace should be a
priority in everyone's workout schedule.
The concept of training specificity can be fruitfully applied to
form drills, plyometrics, and other strength-building exercises as well.
In the April 1999 issue of Running
Research News, Owen Anderson explains how this should work: "Since the
gains in strength ... are specific to the speed of movement utilized during
the strength work, it's important to attempt to match your speed of
movement as you strength-train with the actual speeds of movement
associated with your sport." Furthermore, Anderson continues, "since
running is a 'one-legged sport' (full body weight is borne by one leg at a
time), it's important to avoid ... seated or lying-down postures while
carrying out strengthening exercises; instead, utilize strength routines
which require most or all of body weight to be supported by one leg, not by
both. Thus, one-leg squats are better than traditional squats, one-leg
hops ... are better than two-leg jumping, etc."
In short, the training principle of specificity is utterly logical,
is supported by a variety of scientific studies, and can be used to address
a wide range of training-related questions. Of course, no single principle
can possibly encapsulate everything distance runners need to know about
training, but this one comes closer than most. When in doubt, be