Study: Zero-Drop Cushioned Shoes Show No Difference in Injury Rates

The single best running shoe for injury prevention still hasn’t been identified.

In the quest to avoid injuries, runners leave no stone unturned. Consider sticks and foam rollers; massage and chiropractic (and many other therapies); stretching and strengthening; anti-inflammatories and various supplements; diet and hydration.

But the most common and most-hoped-for injury saviour is shoe selection. Surely, there must be a running shoe that exceeds all others in its injury-prevention qualities. Or so many runners would like to believe.

Unfortunately, research reports indicate it’s not that easy. The single best injury-prevention shoe hasn’t been identified yet. A recent study reaches the same conclusion about one of the newer shoe types: cushioned, zero-drop shoes, which have the same heel and forefoot height with plenty of cushioning underneath. “We found that overall shoe drop was not associated with injury risk,” wrote a team from the Luxembourg Institute of Health.

This doesn’t mean that zero-drop shoes cause running injuries. It appears, however, that neither are they associated with a decline in injuries.

The result came as a surprise to the researchers, who had hypothesised that they would see more injuries in the zero-drop cushioned shoes. They based this outlook on their reading of data regarding zero-drop minimalist shoes. “We may not have seen more injuries because runners had similar cushioning in all the conditions we tested,” Laurent Malisoux, Ph.D., told Runner’s World. “As a result, they might not have had to change their running styles, so there was also no change in injuries.”

The Luxembourg study involved nearly 200 runners wearing zero-drop cushioned shoes (D0) and an equivalent number wearing cosmetically identical shoes except for their 10-millimetre drop from heel to toe (D10). This approach constitutes a randomised controlled trial, a high form of experimental design. Also, neither runners nor researchers were told which shoe the subjects were wearing, though the runners might have been able to figure out certain things about their test shoe. Hence, it wasn’t a completely double-blinded trial. The D0 shoes had heel and forefoot heights of 21 millimetres each, while the D10 shoes had a 24-millimetre heel and a 14-millimetre forefoot.

The shoes were provided by a small company, Kalenji, that was unfamiliar to the majority of subjects. Only five percent had worn Kalenji shoes before. In that regard, 95 per cent of subjects were wearing shoes that were new to them. Subjects had an average age of 38, were 60 per cent male, had been running for about eight years, had normal BMIs, and had suffered no recent injuries.

The runners were followed for six months in their new shoes. During that time, 21.6 per cent of the runners in D10 shoes had an injury versus 24.6 per cent in the D0 shoes. The difference was not statistically significant.

When the researchers performed additional analyses, they found that injuries in their subject pool were linked to previous injury and to increasing numbers of workouts per week. Also, occasional runners were less likely to get injured in zero-drop shoes than more regular runners.

There was some indication that zero-drop shoes offered protection from knee injuries but were less protective for foot injuries. Other studies have found a similar link between drop and location of specific injuries. It appears that low-drop shoes are good for the knees, and higher-drop shoes for the feet and lower legs.

“Some shoe characteristics do influence the risk of running-related injury, but the effect of a particular feature might depend on the runner’s profile, including his experience, foot type, weight, and running style,” Malisoux said. “Also the magnitude of the effect that running shoes have is often lower than what runners commonly believe.”

In other words, some shoes might help with some injuries, but there is no universal shoe for all injuries. Also, don’t depend on a new pair of shoes to prevent injuries. Train smart.


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