Effects of kinesio tape on countermovement jump kinetic variables in physically active females with flat feet before and after fatigue: a randomized controlled trial

Abstract

Abstract Background Flatfoot, characterized by a reduced medial longitudinal arch, alters lower-limb biomechanics and affects vertical ground reaction force(vGRF) during dynamic tasks like jumping. Kinesio taping (KT) is often used to support foot posture; however, its efficacy under high-load conditions—such as jumping, which increases arch stress, and fatigue, which reduces muscular support—remains unclear AQ1 . Methods This double-blind randomized controlled trial included 46 physically active females with flexible flat feet (arch height ratio < 0.221),assigned to KT or sham groups. Participants performed countermovement jumps (CMJs) under fresh and fatigued conditions, with andwithout taping. Fatigue was induced via lateral hopping, and KT was applied to the foot arches and tibialis posterior. vGRF variableswere assessed across all conditions and categorized into three functional domains: propulsion (eccentric and concentric peak force andpower, amortization time and force, concentric rate of force development, and eccentric stiffness); flight (jump height and reactivestrength index); and landing (landing stiffness and rate of force development). Navicular drop was also measured only under pre-fatigueconditions AQ2 . Results Significant main effects of group, taping condition, and their interaction were observed for navicular drop, all with large effect sizes.KT reduced arch collapse by 17.8%, compared to 0.9% in the sham group. No significant effects of group or taping were found forvGRF variables. In contrast, fatigue significantly reduced jump height and increased force- and stiffness-related metrics across bothgroups (Benjamini–Hochberg adjusted p < 0.05), all with large effect sizes AQ3 . Conclusions KT applied to the foot arches and tibialis posterior had no effect on dynamic performance, and the static improvement did not reachclinical significance. In contrast, fatigue significantly reduced jump height and increased force- and stiffness-related parameters acrossboth KT and sham groups, likely reflecting compensatory neuromechanical strategies in individuals with flexible flat feet. No tapingeffect was observed during CMJs performed under both non-fatigued and fatigued conditions. These findings suggest that KT offerslimited functional benefit during dynamic tasks in this population. Future studies should investigate alternative taping techniques oradjunctive interventions that more effectively support performance under high-load or fatigued states in individuals with flexible flatfeet.