In a surprising new twist of science, a study published in The Orthopaedic Journal of Sports Medicine now suggests that maximal running shoes actually increase the impact on a runner’s body, simultaneously increasing his or her risk of sustaining an injury! Maximal running shoes feature increased cushioning, particularly in the forefoot region of the midsole.
To reach this conclusion, researchers in the Functional Orthopedic Research Center of Excellence (FORCE) Lab studied 15 female runners wearing neutral and maximal sneakers, evaluating the impacts on runners' feet and legs before and after a simulated 5,000 meter run on a treadmill (about 3 miles). Each subject wore a neutral running shoe (specifically, the New Balance 880) for one test and then, after a seven to 10-day waiting period, repeated the run wearing a maximal shoe (Hoke One One Bondi 4). In each test, 3-D movements and forces were measured by monitoring reflective markers placed on the runners' shoes and legs and by having the subjects run over a device that recorded the forces being applied as their feet hit the surface.
Oddly, researchers found that runners experienced a higher impact peak and increased loading rate when wearing the maximal shoes, putting their wearers at greater risk of injuries like plantar fasciitis and stress fractures.
FORCE Lab director Christine Pollard said, "We were surprised by these results. We thought we would see the opposite. Typically, increased cushioning results in a reduction in the impact peak and loading rate of the vertical ground reaction force. We suspect that the large amount of cushioning across the entire midsole caused the runners to rely more on the shoe than on their own internal structures to attenuate these forces."
The research is another voice in the long-running debate over optimal running shoes, and will likely score a point in favor of those who advocate minimalist running. Of course, Pollard cautions, this study was only conducted with female subjects, and she says to expect that a study with male runners might produce different results. "We know that gender differences in running biomechanics do exist," she concludes.