A new study by orthopedic surgeons in the United Kingdom has found that marathon running might be good for a person’s knees.

The study examined a group of beginner runners who participated in a four-month training program to examine running’s impact on their knees before and after they completed a marathon. More than 30 million people worldwide participate in long-distance running each year.

The runners ranged in age from 25 to 73 years old, with an average age of 44.

The researchers took MRIs of the runners’ knees six months before they ran their first marathon and two weeks after they completed it.

The MRIs showed stronger knees after the runners completed the marathon and a significant reduction in the amount of damage to knee bone and cartilage. These findings suggest people who participate in distance running might be developing healthier joints, even if they had knee damage before beginning the exercise regimen.

But what if you’re not planning on running a marathon? The researchers said people can do exercises similar to those used by runners in training to help keep their knees stronger. It may also help dispel the notion that running damages knees, which often dissuades people from trying the sport. The researchers are conducting follow-up studies of the runners’ knees to see if anything if anything changes after six-month intervals.

Even if you’re not training for long-distance running but just want to get more exercise outdoors, you can help prevent an injury by wearing properly fitted shoes, warming up and stretching before setting off and stretching again when you finish. Taking these important steps can lead to better health.