Comparison of the rigidity and forefoot – Rearfoot kinematics from three forefoot tracking marker clusters during walking and weight-bearing foot pronation-supination

Due to the relative motion among the foot rays, the present study aimed to compare the rigidity as well as the forefoot – rearfoot kinematics obtained from three forefoot tracking marker clusters during walking and foot pronation-supination (PROSUP). Nineteen healthy adults performed six walking trials and ten cycles of foot PROSUP movements recorded by an optoelectronic system. Rearfoot's and forefoot's coordinate system were equal for all setups, only the forefoot's tracking markers locations varied among them, which were: (1st) a typical cluster, focusing on the proximal forefoot, (2nd) a second typical cluster, focusing on the distal forefoot and outer metatarsals, and (3rd) a new cluster proposition, focusing on the distal forefoot and central metatarsals. Cluster rigidity was the normalized intra-markers residual, and forefoot – rearfoot angles were the forefoot motion relative to the rearfoot at the peak of each plane of motion. Repeated-measures ANOVA with pairwise comparisons (α=0.05) revealed that the 3rd cluster had the smallest residual (p