Although it is difficult to estimate, various studies suggest that between 30% and 75% of runners suffer injuries over the course of a year. What causes so much injury is almost a mystery to researchers since there are so many factors that influence running mechanics that isolating a single thing is quite a difficult task even for scientists who specialize in it.

But a recent study recent study from Harvard could shed some light on the subject. The researchers recruited 249 amateur women runners who ran at least 32 kilometers per week. They analyzed their stride and tracked them for two years. During the study, 57% of the participants suffered some injury while the rest remained uninjured, but that was not the most relevant finding.

The researchers analyzed the differences between the group of participants who suffered an injury severe enough to require medical intervention and the group that had never been injured in their lives, and they found a notable difference between these two extreme groups.

The group that was injured landed with more force and spent more time with their foot in contact with the ground than the group that had never suffered injury. The difference is minimal, just 50 milliseconds, but repeated thousands of times it can have a significant impact on the joints, muscles, or bones.

One of the athletes had run dozens of marathons and had never been injured. When analyzing her data they noticed that her ground contact was particularly soft (cushioned). A valid way to know if you are landing too hard against the ground is to listen: a soft landing is silent while a hard landing against the ground makes more noise.

In summary, the research results suggest that a softer landing (ground contact) could reduce the chances of suffering an injury. It is important to clarify that the study was conducted with women who landed with their heel, because the majority of runners do so.