It keeps getting trickier to pick the right running shoes, at least if you’re looking for simple answers. Four years ago, a team of biomechanics experts found that motion-control shoes did little to limit injuries among the very over-pronators the shoes were designed to help. In fact, a simple “neutral” shoe worked better for these runners.
Then Army researchers found that using the classic “wet test” to aid shoe selection didn’t limit injuries in basic-training recruits.
Now you can throw out what you probably think about cushioned shoes. A new study from the Sports Medicine Research Laboratory in Luxembourg reports no difference in injury rates between runners in “soft” (i.e., cushioned) shoes vs. hard shoes.
The Luxembourg researchers used a double-blind, randomised, controlled design to follow 215 matched runners for five months. The subjects wore identical shoes provided by “a renowned sports equipment manufacturer.” Except the shoe midsoles weren’t truly identical; they just looked alike. In fact, one midsole was 15 per cent harder than the other. All shoes had a 12mm drop from heel to toe.
The study team hypothesised that they would see fewer injuries in the runners wearing the soft-midsole shoes. After all, they note: “The shock-absorbing qualities of a running shoe are put forward as being especially important, since they influence repetitive impact forces that could be responsible for microtrauma and overuse injuries.”
Their results disproved their hypothesis. “Within our study conditions, midsole hardness of modern cushioned running shoes did not influence running-related injury risk.” They were particularly surprised that the softer midsoles didn’t even prove protective for heavy runners who are often advised to use shoes with extra cushioning.
The runners in this study generally ran twice a week, covering about 10km at a time, at just under 6:15 pace.
The best predictor of a running injury in this group was a prior injury. Higher perceived exertion while running and higher BMI were also associated with more injuries (but injury incidence in the high-BMI group was the same in both types of midsoles).
Participation in other sports lowered injury incidence, as did running experience in the year prior to the study. Beginners, the researchers theorise, probably make more training mistakes that lead to injury.
The results of this study confirm those from a previous study that found cushioned insoles ineffective at reducing injuries.