The already “complex task” of designing shoes capable of providing proper cushioning for all types of runners just got even more complex.
That’s the word from Ghent University in Belgium, where a team of researchers led by U.S. biomechanics expert Ned Frederick claim to have discovered a new type of runner: the “atypical rearfoot striker.”
Previously, scientists had separated runners into three categories: rearfoot, midfoot, and forefoot strikers. Now, it seems, not everyone prone to hitting the ground heel first does so in the same way, Runner’s World reports.
According to the researchers, typical rearfoot strikers hit with their heels and transition gradually forward, using their body’s natural heel pads and the cushions built into their sneakers’ midsoles.
This approach produces “moderate loading rates” and likely makes typical rearfoot strikers less susceptible to injury than their atypical counterparts.
That’s because after landing on the heel, atypical rearfoot strikers move more quickly to their forefeet, producing higher loading rates. Despite these key differences, the two types of rearfoot strikers seem to share one thing in common: They’re not as fast as their midfoot peers.
As part of the study, Frederick and his team had 55 seasoned Belgian road runners hoof it across a force plate at four speeds, the fastest being a 4:19 mile pace, the slowest an 8:22. With the latter, they found that 82 percent of runners landed on their rearfoot, while a mere 18 percent favored the midfoot.
At the faster 4:19 pace, meanwhile, only 46 percent came down on their heels, while 32 percent went for the midfoot and 22 percent landed on the forefoot.
Does this mean midfoot striking leads to faster running, or is it the other way around? Fittingly enough, it’s complicated, though researchers believe they have the answer.
“Our results suggest that the greater percent of midfoot striking in elite runners might just be a consequence of their running speeds,” they write.