When it comes to running injuries, a lot of the focus falls on your stride pattern and how often you are running, and rightfully so. However, a new study published in the Scandinavian Journal of Medicine & Science in Sports found that horizontal force plays a significant role in predicting a person’s running injury likelihood.
Horizontal Forces and Running
For their study, researchers put 65 women through a 15-week half marathon training program that called for them to run at a moderately hard pace. Researchers tracked injury rates related to overuse as opposed to injuries like ankle sprains. They assumed that vertical loading rates, or how hard a person hit the ground with every step, would have the greatest correlation with injury rates, but they were wrong. In fact, vertical injury rate wasn’t linked to an increase in injury likelihood among the study participants.
However, one factor stood out from the rest in association with injury rate likelihood, and that was peak braking force. Peak braking force is defined as the maximum amount of force opposite to the direction of travel. Based on these measurements, researchers divided study participants into three groups based on whether they had low, medium or high maximum braking force. Once divided, researchers noticed that runners in the highest peak braking group were eight times more likely to suffer a stress-related running injury compared to the low group, and five times more likely to suffer the same injury compared to the medium braking force group.
“Bone withstands vertical (compressive) forces better than it does horizontal (shear) forces,” said Chris Napier, lead researcher and physiotherapist, in an email to Runner’s World. “Most joints and soft-tissue structures in the lower extremities are built to withstand these same vertical forces, so perhaps they fare worse against the shear forces from increased braking.”
Decreasing Horizontal Running Force
Interestingly, Napier found that there was no difference in injury rate among runners who run with a heel-strike pattern or a midfoot-strike pattern, so it’s not your strike pattern that you need to be worried about for decreasing your brake force. And while you won’t be able to tell what group you’d belong to unless you visited a testing facility, Napier found that when he told participants to focus on lowering their braking forces, all runners were able to reduce those forces from high to low.
Most of the runners were able to achieve this by shortening their stride and trying to “land softly.” You can reduce your braking forces by doing the same, and by being aware of the forces you’re putting on your feet as you slow down or stop. If you’re a pretty herky jerky runner, reduce your stride a little and focus on landing lightly, and odds are you’ll decrease your injury likelihood!
