Skipping — an exercise many people may not have tried since their school days on the playground — may actually be a great grown-up workout because it puts less stress on the knees than running while burning more calories, a recent study suggests.

Running-related injuries are on the rise, and as many as 79% of runners report injuries in any given year, researchers note online in Gait and Posture.

Running mechanics produce large amounts of force on the body with every stride, which means runners often develop repetitive stress injuries by not allowing sufficient recovery time.

For the study, researchers compared the contact force on the knee for 20 healthy, young adults when they ran and skipped — the knee-high hopping activity rather than jumping using a rope — at the same speed.