If you feel like running and dead lifts go together about as well as swimming and Joe Frazier, you need to rethink your cross training. A new study shows that by incorporating heavy lifting into their workouts, runners can significantly improve their running economy, helping them run faster for longer.

In the study, Italian researchers split a group of master runners (most of them in their mid-40s) into two groups, one that did numerous reps at lower weight (about 70 percent of their max) and another that did fewer reps at higher weight (closer to 90 percent of their max). The runners performing fewer reps of higher weight reaped the greatest rewards. "Running economy is a better predictor of endurance performance than maximal oxygen uptake and does not seem to change with advancing age," says Maria Frencesca Piacentini, the lead author on the study.

Aside from greater running economy, Piacentini says that max strength training programs also serve to improve running technique. Michael Bultman, a strength and conditioning coach at CrossfitNYC, agrees and says that lifting routines like the type in the study have numerous benefits for runners. "Distance runners that lift and squat get stronger and therefore can run faster," Bultman said. "And beyond muscles, lifters build stronger ligaments and tendons, which helps prevent injuries."

Bultman also noted that runners who engage in strength training (especially dead lifts) will feel the difference when they need it most: their kick at the end of a race.