Expanding our knowledge of ankle and foot interactions in walking

The adaptable structure and function of the foot and ankle play a pivotal role in how we walk. This dynamic structure-function interaction acts like a spring because it absorbs energy when our foot contacts the ground and returns this energy to propel our leg forward. Due to the complex anatomy and adaptable function of the foot and ankle, it has been difficult to develop a technique that models the interaction of different segments within the foot. Therefore, the purpose of this study was to expand current understanding of these structure-function relationships during walking by analyzing ankle and foot power in a novel segment by segment manner. Fourteen, healthy children walked over-ground at a self-selected pace while targeting three different foot placements on two adjacent force platforms, allowing us to analyze the power and work contributions of select foot segments (toe, forefoot, hindfoot). This novel approach revealed that while the overall foot-ankle complex acts like a spring, the foot segments have different functions throughout walking. The big toe absorbs a small amount of energy just before push-off (acting like a damper), forefoot-toe interaction mostly absorbs energy (damper), and the hindfoot-forefoot absorbs energy in early stance (damper) and then generates energy before push-off (spring). In addition to validating this novel modeling approach, we were able to revise the current understanding of the foot-ankle and are now applying this new framework to answer both basic and applied clinical research questions