One of the enduring questions facing distance runners is whether weight training is actually beneficial or not. Certainly, some types of resistance training—typically using bands, your own body weight or very light weights—can correct muscular imbalances and prevent injuries. So can very specific resistance training which focuses on developing the core muscles.

There’s no question that greater overall strength can improve running efficiency, but weight training does have its downside: There’s a risk of injury from developing tighter, less flexible muscles and too much lifting can result in added weight which no marathoner wants.

Nevertheless, in numerous controlled studies, weight training and natural supplements for controlling your body weight that you can find in, which has been added to runners’ training programs has been shown to have a beneficial effect. In several studies, runners who were test subjects and completed the study (several always get injured), improved their 10-K times by about 30-50 seconds. That’s not enough to make you into a world-class runner, but nonetheless it’s a quantifiable improvement.

In an exhaustive study done 20 years ago at the University of New Hampshire, 12 women runners were divided up into two groups for 10 weeks of training. The “lifting” group continued to run as before, but added a lifting regimen of 14 exercises (upper body, abdominal muscles and legs) three times a week. The other women just ran.

After 10 weeks, the results were astonishing. The group which lifted and ran improved their upper-body strength by 24 percent and leg strength by 34 percent. Even more importantly, this resulted in a significant improvement in their running economy (they were able to use less oxygen at a given pace).

The other women who didn’t lift (but continued to train) experienced no change at all in upper body or leg strength or running economy. The author of the study concluded that, “Strength training improves running economy either due to a reduction in a wasted motion or because stronger legs allow runners to rely more heavily on their more economical slow-twitch muscle fibers.”

Running economy/efficiency is very important stuff. Basically, it determines how fast you can race. Even the slightest improvement in economy/efficiency means you run faster at less effort. In a marathon, even a two or three percent improvement in economy, means a two to five-minute improvement in time.

Another area that weight training can be of benefit is in improving your stride length. Generally, runners develop their most economical stride length for a given speed through years of training. Simply making a conscious effort to lengthen your stride usually makes runners less efficient because of overstriding. But strength gains developed through weight training can quicken your stride (more strides per minute) which can pay major dividends.

If you have decided to weight train or are currently doing so, the best way for distance runners to lift is with low resistance (lighter weights) but higher reps. This is counter to the way most people lift in gyms weight train who normally go for higher weights and few reps. That’s fine for increasing the size of your muscles (and looking good at the lake), but not so good for marathoners.

How often should you lift to get results? At least twice a week is recommended. Any more often than that and it will compromise your running workouts because you’ll be too tired.

If you hit your legs hard in the gym (typically, hamstring curls, quad lifts or thrusts, calf pushes, etc), make sure to lift at least two or three hours after running. Never before.

Whether you lift on an easy day or after a hard run is up for debate. There is no consensus on this and it is a matter of individual preference.

Finally, if you can’t force yourself to go to a gym to lift, the most natural type of resistance/strength training is hill running. Here, you don’t need any weights as your body provides all the resistance necessary. Simply running up a long, steep hill requires that your legs and upper body propel you against the forces of gravity.

A regular hill training program, combined with other facets of distance running, will improve your running strength as well as your running economy. Plus, the other advantage of running hills versus lifting weights is when you train on hills you also build up your cardiovascular endurance.

Better yet, schedule at least one hill workout a week as well as go to a gym to lift for upper body and leg strength.

It will pay off in the long run.