This is a very popular question. Read running magazines and you will think
the answer is obvious. Well, do a little more research and the answer becomes
much more fuzzy.
The first research I suggest doing for any questions of training is to look
at what the elite runners do. These are the people who have gotten the most out
of their training. They have figured out what is worth their time and energy and
what isn't. So, what do the elite runners do? Well, very few elite runners who
focus on events of 5k and up go anywhere near weight rooms. That doesn't mean
they don't do strength training, though. The most popular form of strength
training for elites is running hills. Repeats, circuits, easy and long runs over
hills, fartleks, you name it. The bottom line is that they spend a lot of time
running up and down. That's not all they do, though. Core strengthening is
something that almost all of them do. Abdominal training is done by many elites. Circuit training is also popular with some, as
well as body weight exercises, like pushups, pullups, step-ups, one-leg squats
or lunges, one-leg hops or toe raises. Some, although they are a distinct
minority, especially as their goal distance becomes longer, also lift weights.
Another form of research that I like to look through would be scientific
studies. So, what do they say? Well, not a whole lot for lifting weights for
distance runners. Studies have shown that lifting weights is most likely
beneficial for racing distances that take less than 10 minutes to complete. What
about the longer distances? Well, things change sharply. In fact, I have seen
only one study that showed lifting weights is beneficial for "well trained"
athletes and I found that study to be questionable. That study also said it is
beneficial for the 5k but findings were inconclusive once the race distance was
over 20 minutes. I have yet to see one study that found weight training to be
beneficial for anything longer than that. What about athletes who are
not "well trained"? Well, studies have shown that adding weight
lifting on top of their current training routine does help improve performance,
which makes sense. You are increasing training load. Regardless of what that
training is, increasing training load will increase fitness. But there's a
catch. Using that increased training load to do more running instead of lifting
weights leads to much more significant performance improvements. In the end,
almost all studies have found that lifting weights has no statistically
significant positive effect on racing performance in events of longer than 10
minutes and some suggest that there may be a negative effect on performance.
What about other forms of strength training? Well, studies have shown that
running hills is one of the most beneficial forms of training that a runner can
do. Circuit training, core training, and body weight exercises haven't been
studied enough to offer any quality assessments.
Of course, there is one variable that I have purposely left out so far.
Many people believe lifting weights is good for injury prevention. While this
sounds great, for the typical biomechanically sound runner, there is simply no
evidence supporting these claims. In fact, in an unscientific study of one, my
injury rates have been higher when lifting weights (under the supervision of
trainers and strength and conditioning coaches) than when not lifting weights.
On the other hand, if you have a biomechanical inefficiency, lifting weights may
make sense to correct any imbalances.
In the end, there is not a whole lot of evidence supporting the use of weight
training for performance benefit. This doesn't mean it's not worth a shot.
Experiment, we are all studies of one. However, as I always say, why assume you
are in the minority when chances are you are in the majority? If weight training
isn't working for you, move on and find something that would make better use of
your limited training time and energy. If you have to decide between a few extra
miles on the roads or hitting the weight room, by all means, run a few extra
miles. That is where you are going to get the best performance benefit.
In closing, I would like to offer a link to a Peak
Performance Online article about strength training. I have been using the
exercises mentioned in this article since my college days and find them to be
much more beneficial than anything I could do in the weight room.