A proposal to investigate foot and ankle joint kinetics and foot muscle properties in chronic ankle instability subjects

We provided the rational to evaluate foot kinetics during running and more challenging tasks and to assess the impact of intrinsic foot muscle (IFM) properties on kinetics and kinematics. This work was presented at the 47ème Congrès de la Société de Biomécanique in the form of a Poster. We detailed the absorptive and propulsive characteristics (moment and power) of the Chopart and Lisfranc joints, based on preliminary statistical analysis on 5 healthy participants performing side cutting tasks. An abstract was also published in a Supplement of "Computer Methods in Biomechanics and Biomedical Engineering" (pages S248-S249 of doi : 10.1080/10255842.2022.2116885). We detailed the protocol of our study which aims (1) to compare multi-segment foot joint kinetics between participants with chronic ankle instability (CAI), lateral ankle sprain copers and healthy controls during running, side cutting and crossing an obstacle while running and (2) to evaluate the impact of IFM properties and fatigue on lower limb biomechanics during the same three tasks. Ultimately, our study will include three participant subgroups, while most previous studies did not include ankle sprain copers. To our knowledge, there are currently no studies assessing multi-segment foot kinetics during any locomotor task in subjects with CAI. Although, it was shown to be feasible by Deschamps et al. (2020) in healthy subject, providing moments and powers at the ankle, Chopart, Lisfranc and metatarsophalangeal joints. Also, we are not aware of any study assessing the impact of IFM properties on multi-segment biomechanics, hence IFM play important roles in foot stabilisation