This is guest post by Everday Health contributor Lynn Grieger.

One of the women in my running group told me that she doesn’t need to strength train because her legs are strong from running up and down the mountains around our home in Vermont. Her legs may be strong, but resistance training gives her several important benefits running alone can’t match: increased speed, improved running economy, strong bones, and decreased risk of osteoporosis.

Research Backs Up Gains from Strength Training

According to this National Osteoporosis Foundation article, two types of exercise maintain strong bones and decrease risk of osteoporosis: resistance and weight-bearing. Running itself is weight-bearing exercise, but running alone won’t give you the same benefit as incorporating strength training 2-3 times per week.

1 out of every 3 women over the age of 40 has some bone loss, and more women die of osteoporosis-related complications than of breast cancer. Miriam Nelson, PhD, professor of Nutrition at the Friedman School of Nutrition Science and Policy, and founder and director of the John Hancock Research Center on Physical Activity, Nutrition, and Obesity Prevention at Tufts University, developed the Strong Women, Strong Bones program to prevent or manage osteoporosis with a combination of strength and weight-bearing exercise, good nutrition, and medical management.

Balance, Strength, and To-Die-For Muscles

If strength training is so good for us, why do we skip the gym in favor of a brisk run outside? Blame it on too many demands with limited time or fear of the unknown.

I asked several runners why they fit strength training into their weekly routine:

Cindy H: I get tired easily and strength training makes me feel good about myself especially as I see progress in a weight I can lift or being more toned. It has helped in running as my upper body does not get so tired and aching.

Kathy L: About two months ago I began doing Les Mills Body Pump classes. What got me motivated was noticing my sagging “Bingo Wings‚” I am developing upper body strength and core strength. And as strong as we runners think our legs are, I have noticed great improvement in the large muscle groups in my legs. The lifting exercises work the back, glutes, hamstrings and quads. I find the classes very challenging, and I believe it is helping add some balance to my fitness routine. Stronger muscles are more efficient and more attractive.

Kim M: I recently started doing Pilates and notice that it helps in running and biking. Engaging my core helps me power up hills more so than doing specific hill workouts.

Fern W: Through Pilates I learned body awareness, breathing techniques and gained more strength than anything else I have ever tried. The strength and flexibility guard against injury during running, cycling and skiing and hiking. The strong abdominals definitely make me a better runner. Also, I think that a well-toned body looks more attractive, and I love to strive for the hard to attain!

Laurie F: I feel more balanced overall when I strength train and less jiggly when I run!!

Guest blogger Lynn Grieger is a RRCA certified running coach who leads women’s running groups in southwestern Vermont and contributes to Everyday Health, overseeing its fitness and calorie counter content. She includes circuit training in her weekly exercise routine along with running, swimming and biking.