Study on the effects of shoe cushioning on trail-running: perception, bench test and biomechanical approach

This work aimed to investigate the association between the perceived cushioning of a set of trail-running shoes with both their mechanical response to the impact test and the acceleration of lower limb segments while running indoors and outdoors. Earlier studies have typically focussed on the effect of road-running shoe cushioning, whereas very few have examined the perception of trail runners and outdoor trail-running conditions. Seven trail runners were trained to become reliable in evaluating the level of cushioning on a scale ranging from 0 to 100 and then asked to rate the cushioning of eight trail-running shoes while running. Shoe specimens were mechanically characterized through an impact test. In addition, the effect on running biomechanics was tested by wearing two accelerometers on the tibia and foot. The in-lab impact test revealed that the perceived cushioning was inversely associated with the force amplitude and directly associated with the impact duration. The running test showed that the median frequency of the tibial acceleration during the first 25% of the stance phase decreases with increasing cushioning during both indoor (p = 0.02, rs = −0.83) and outdoor conditions (p < 0.001, rs = −0.79). In conclusion, the perceived cushioning was quantitatively associated with the outcomes of impact and running tests.