Running, while a popular activity and good cardio, can be hard on the joints. And a running injury can affect people’s training for weeks, if not months.

For decades, researchers have studied the biomechanics of runners to understand how to minimize injury. Most of that research has looked at vertical forces through the leg as feet hit the ground.

As a result of this research, it has been suggested that “average vertical loading rate” is an accurate predictor of injuries among runners. To reduce her chances of injury, then, a runner would try to land softly with each foot strike and aim to avoid striking the heel exclusively. This is easy to believe because vertical forces during running are up to ten times greater than horizontal forces.

However, a new study suggests that horizontal braking forces is a more accurate predicting metric—by far.

The Cause of Injuries

Research from the University of British Columbia observed several dozen female runners. Their three-dimensional gait analysis was followed up with a four-month training program to monitor injuries. The results were startling.

The study, published in the Scandinavian Journal of Medicine & Science in Sports, found that braking force was the only measure with meaningful accuracy: those with the highest braking forces were much likelier to sustain an injury—eight times more likely, in fact, than those with the lowest braking forces!

“65 participants were included in the final analysis, with a 33.8% injury rate,” the paper reads. “Peak braking force was the only kinetic variable that was a significant predictor of running-related injury.”

Now we know what the problem is. The next question is: how do we solve it?

A Lower-Injury Gait

In any athletic endeavour, there is no way to prevent injuries with perfect success. But not being able to guarantee injury prevention is no reason to work toward more favourable odds. Nobody believes they will be injured until they are—and then they almost always spend their recovery period wishing they had prepared more preventative measures.

The best predictors of high braking force are stride length and running speed. This, interestingly, is regardless of foot strike.

One option is therefore to slow down. But what’s the fun in that?

A better option is to increase your cadence, or how many steps you take in a minute at any particular speed. You can reduce your risk of injury by adding 5 to 10 steps per minute at your tempo pace. (This helps triathletes, too, because their body can transition from cycling to running more easily when the cadences sync. An optimal cycling cadence is 85 to 100 RPM.  

Running softly helps, too. Aim to land light on the foot, seeking silent steps.

Or choose an alternative to running, such as jump rope or cycling.