Dancers With Chronic Ankle Instability Have Different Regional Plantar Force During Single-Leg Jump Landing.

Background: It is already known that the prevalence of ankle sprain is high in dancers, leading to chronic ankle instability (CAI) and, consequently, affecting jump landing. Therefore, methods that allow the early identification of jump landing alterations related to CAI are necessary. Research Question: This study aimed to investigate if regional plantar force estimated from plantar pressure distribution is different between dancers with and without ankle instability during jump landing. Methods: Female dancers with (n = 12) and without (n = 14) CAI performed single-leg jumps on a force plate (FP), with the insole of a dynamic plantar pressure system inside the ballet shoe. Peak vertical ground reaction force (measured by FP) and peak plantar force of 8 different foot regions (estimated by plantar pressure distribution) were compared between the groups in the first 200 ms after landing, using the t-test and 2-way ANOVA, respectively. Results: No differences were found between the groups considering the peak vertical ground reaction force. There was a higher plantar force on the lateral hindfoot in the group with CAI. Significance: Considering that the higher plantar force on the lateral hindfoot is in accordance with the greater inversion found in people with ankle instability and during sprains, insole dynamic plantar pressure systems were able to identify differences in the jump landing of dancers with and without ankle instability and could be used to early identify risky landing patterns, as well as in real-time feedback during treatment or preventive exercise programs.