Effect of coordination training with and without stochastic resonance stimulation on dynamic postural stability of subjects with functional ankle instability and subjects with stable ankles

Objective: To examine the effects of coordination training with and without stochastic resonance (SR) stimulation on dynamic postural stability. Design: Experimental with repeated measures. Setting: Research Laboratory. Participants: Thirty subjects with functional ankle instability (FAI) and 30 healthy subjects. Interventions: Subjects were assigned to a conventional coordination training group, SR stimulation coordination training group, or control group. Training groups performed coordination exercises for 6 weeks. Single leg jump-landing tests were performed before training began (pretest), and then once every 2 weeks. Jump-landing tests required subjects to land on a single leg on a force plate and stabilize quickly. Main Outcome Measures: Anterior/posterior (A/P) and medial/lateral (M/L) time-to-stabilization (TTS). Results: The FAI group improved their A/P TTS over their pretest by 16% (test 2), 22% (test 3), and 22% (posttest). They also improved their M/L TTS over their pretest by 16% (test 3) and 22% (posttest). Control groups did not improve their TTS (P > 0.05). SR stimulation did not statistically influence TTS (P > 0.05). Effect sizes (ES), however, for our 3-way interaction analyses for A/P TTS (ES = 0.40) and M/L TTS (ES = 0.30) suggested that SR stimulation improved the FAI group's M/L TTS after 2 weeks of training, and improved their A/P TTS and M/L TTS to a greater degree after 4 weeks than coordination training alone. Conclusion: Coordination training can improve dynamic postural instabilities associated with FAI. SR stimulation might be an alternative therapy for FAI, as this stimulation might improve dynamic postural stability more quickly and to a greater extent than coordination training without SR stimulation.