Does Kinesio taping of tibialis posterior or peroneus longus have an immediate effect on improving foot posture, dynamic balance, and biomechanical variables in young women with flexible flatfoot?

Background Flexible flatfoot is common in young adults. One of its causes is the failure of dynamic stabilizers, which play an important role in the medial longitudinal arch support, and their appropriate function is necessary for the integrity of the lower extremity and the spine. Objective The study aimed to determine Kinesio taping on which extrinsic foot muscle provides greater benefit regarding enhancement of foot posture, dynamic balance, and biomechanical parameters in functional tasks immediately. Methods Thirty women were recruited for the study. They were randomly divided into groups (A = 15, B = 15). In group A, Kinesio taping was applied on the tibialis posterior (TP), and in group B, Kinesio taping was applied on the peroneus longus (PL) and remained for 30 min. Outcome measures were the navicular drop test (NDT), foot posture index (FPI), Y-balance test, and biomechanical parameters in functional tasks. Before/After within-group and between-group comparisons of outcome measures were performed. Results NDT and FPI decreased in both groups (p < 0.05) with no significant difference between groups. In group A, maximum total force of the stance phase (MaxTFSP) during running increased, and some temporal parameters were changed. (p < 0.05). In group B, Y-balance test improved in all directions, and the width of the gait line during walking increased. There were no significant differences in the postural stability parameters in the within-group comparison, except for mean center of pressure displacement in group B (p = 0.04). Conclusion Kinesio taping of both muscles could improve foot posture. TP Kinesio taping can increase the MaxTFSP during running and alter some temporal parameters during walking and running tasks. PL Kinesio taping could lead to better dynamic stability and coordination during dynamic tasks. Each muscle can be considered a therapeutic target for a specific purpose.