No / The purpose of this article is determining if and how the kinematic relationship between adjacent body segments changes when an individual’s gait pattern is experimentally manipulated can yield insight into the robustness of the kinematic coupling across the associated joint(s). The aim of this study was to assess the effects on the kinematic coupling between the forefoot, rearfoot and shank during ground contact of running with alteration in foot strike pattern. Twelve subjects ran over-ground using three different foot strike patterns (heel strike, forefoot strike, toe running). Kinematic data were collected of the forefoot, rearfoot and shank, which were modelled as rigid segments. Coupling at the ankle-complex and midfoot joints was assessed using cross-correlation and vector coding techniques. In general good coupling was found between rearfoot frontal plane motion and transverse plane shank rotation regardless of foot strike pattern. Forefoot motion was also strongly coupled with rearfoot frontal plane motion. Subtle differences were noted in the amount of rearfoot eversion transferred into shank internal rotation in the first 10–15% of stance during heel strike running compared to forefoot and toe running, and this was accompanied by small alterations in forefoot kinematics. These findings indicate that during ground contact in running there is strong coupling between the rearfoot and shank via the action of the joints in the ankle-complex. In addition, there was good coupling of both sagittal and transverse plane forefoot with rearfoot frontal plane motion via the action of the midfoot joints.

The main goal of the project was to compare how the Achilles tendon is affected while running with traditional shoes, minimalistic shoes and barefoot. Displacement and strain were calculated both for different shoes and for different foot strike patterns. The calculations were done with a speckle tracking algorithm and displacement was calculated for three different depths in the tendon: deep layer, mid layer and superficial layer. The goal was also to conduct this analysis after a review of the algorithm used. The review of the algorithm focused on the size of the region of interest, kernel size and frequency. Literature study showed that it is more common to use a smaller kernel size, but the same shape. The region of interest was chosen depending on the size of the tendon. Displacement and strain in the Achilles tendon was calculated for seven subjects and the result did not show any difference in amount of mean deformation due to different shoe types or foot strike patterns. It was a small sample group but the result indicated a difference in peak displacement between deep and superficial layer depending on different shoe types and foot strike patterns. The difference in peak displacement between deep and superficial layer was lowest when running barefoot, larger when running with minimalistic shoes and greatest when running with traditional shoes. This result was only achieved when running with rear foot strike pattern. When running with fore foot strike pattern the difference in peak displacement between layers did not change with different conditions. In all conditions the difference in peak displacement between the layers was greater when running with rear foot strike pattern than when running with front foot strike pattern. The deep layer displaced more than the superficial layer (p<0.01) for all conditions and foot strike patterns.