Effects of footwear midsole thickness on running biomechanics.

Shoe manufacturers launch running shoes with increased (e.g., maximalists) or decreased (e.g., minimalists) midsole thickness and claim that they may prevent running injury. Previous studies tested footwear models with different midsole thicknesses on the market but the shoe construct was not strictly comparable. Therefore, in the present study, we examined the effect of midsole thickness, from 1-mm to 29-mm, in a standard test shoe prototype on the vertical loading rates, footstrike angle and temporal spatial parameters in distance runners. Fifteen male habitual rearfoot strikers were recruited from local running clubs. They were asked to run on an instrumented treadmill in shoes with different midsole thicknesses. We found significant interactions between midsole thickness with vertical loading rates (p < 0.001), footstrike angle (p = 0.013), contact time (p < 0.001), cadence (p = 0.003), and stride length (p = 0.004). Specifically, shoes with thinner midsole (1- and 5-mm) significantly increased the vertical loading rates and shortened the contact time, when compared with thicker midsole shoes (25- and 29-mm). However, we did not observe any substantial differences in the footstrike angle, cadence and stride length between other shod conditions. The present study provides biomechanical data regarding the relationship between full spectrum midsole thicknesses and running biomechanics in a group of rearfoot strikers.

Does maximalist footwear lower impact loading during level ground and downhill running?

A new model of running shoes which features an extreme cushioning and an oversized midsole, known as the maximalist (MAX) was launched. This design claims to provide excellent shock absorption, particularly during downhill running. This study sought to assess the effects of MAX on the external impact loading, footstrike pattern, and stride length during level ground and downhill running on an instrumented treadmill. Twenty-seven distance runners completed four 5-minute running trials in the two footwear conditions (MAX and traditional running shoes (TRS)) on a level surface (0%) and downhill (10%-declination). Average and instantaneous loading rates (ILRs), footstrike pattern and stride length were measured during the last minute of each running trial. A 12% greater ILR was observed in downhill running with MAX (p = .045; Cohen's d = 0.44) as compared to TRS. No significant difference was found in the loading rates (p > .589) and stride length (p = .924) when running on a level surface. Majority of runners maintained the same footstrike pattern in both footwear conditions. Findings of this study suggested that MAX might not reduce the external impact loading in runners during level and downhill treadmill running. Instead, this type of footwear may conceivably increase the external impact loading during downhill treadmill running.