This is the best workout for runners, according to sports medicine doctor Jordan Metzl

If you’re a runner, you know that your main motivator for lacing up your sneakers, starting your playlist, and hitting the road is your sheer love for the sport. (Okay, most of the time.) You know it’s doing heaps of good for your body and your mind, but your goal is likely more about reaching a specific distance or achieving a certain speed, not really toning your muscles, per se.

But adding more days and miles to your running regimen isn’t necessarily the best way to achieve these goals. According to sports medicine doctor Jordan Metzl, MD, who has finished over 30 triathlons himself, cross-training can not only help protect you from common injuries, but it can also make you an even better runner—when you do it right.

I called up Dr. Metzl to get the low-down on the ideology behind his runner-fave workout Ironstrength and the scoop on his upcoming event that will bring more than 1,000 fitness lovers together for a sweat sesh on the flight deck of the USS Intrepid.

Keep reading to find out the best way for runners to cross-train.

Well+Good: What exactly is the Ironstrength workout and how did you come up with it?

Dr. Metzl: It’s really a combination of my world as a sports doctor—where people rely on me to not only fix their injuries, but to also stay healthy—and my world as an athlete. I love to do triathlons and different sports. I recognized that when my muscles were stronger, I personally did better and went faster. When I started getting my patients’ muscles stronger, they also did better and hurt less often. Then the goal was to figure out how to get people on mats and strengthen the exercises so they can have the same benefits.

The concept of Ironstrength is teaching people how to strengthen all of their tip-to-toe muscles; their kinetic chain. All of the moves are centered on total body or kinetic chain strengthening. The more parts of that chain you strengthen, the less likely you are to hurt those muscles. It’s also a lot of fun!

How does strength-training make someone a better runner?

Runners notoriously don’t do enough strength training—they only want to run. My colleagues at HSS and I just finished a study with New York Road Runners looking at injury rates in runners. There were two groups: one that strength trained and one that didn’t. The group that strength trained had a slightly lower injury rate than the group that didn’t. The overall concept is, if all you do is run, you’re not strengthening all of the muscles you need—you’re only strengthening some of them.

The reason this becomes important is that every time you hit the ground, you have what’s called a ground reaction force, or a GRF, and the stronger your muscles are, the stronger your kinetic chain, and the less that GRF impacts your body. Your muscles are absorbing more of the force of landing, so your knees and your back and your hips don’t feel as much of that direct pressure with the ground. Stronger muscles makes running not only more enjoyable, but also safer and better.

Strength training achieves two goals: body maintenance and performance. Ironstrength is something people of all ages can do. We have people in their 70s and 80s come to the classes. It not only makes you run better but also reduces their aches and pains because their muscles are stronger.

What can you share about the Ironstrength event you’re hosting on the USS Intrepid? What makes these mega-group workouts so special?

We started doing these community fitness classes about six years ago. It started out really small, with the goal of helping people run triathlons faster. It grew into a whole celebration of all-level fitness. What started out as 20 people has turned into a list of 34,000 people. We started surveying people who come back to the events five or six years in a row, and they do it for the love for community first; second is that the workout is so fun.

For the one on the USS Intrepid, the class is split half in half: Zumba and then an Ironstrength workout. All the events are split with Ironstrength and something else—sometimes it’s yoga, for example. But it gives people a chance to come and try something new that they might not otherwise try.

One of the main things that keeps people healthy is not only movement and activity, but also community. This is a really fun chance to get people together and get them moving.

The desire to work out consistently forever is a big reason why HILIT is trending right now. And attention runners: These are the best foods to eat before and after a run.