Background: Repetitive damage to the ankle joint causes chronic ankle instability, and studies comparing the effects of exercise in open and closed chains as a treatment method are very rare.
Objectives: To investigate the effects of open and closed kinetic exercises on muscle activity and dynamic balance of ankle joint in adults with chronic ankle instability.
Design: Single-blind randomized controlled trial.
Methods: The selected 30 subjects are randomly divided into open kinetic chain exercise experimental group (EGⅠ, n=10), closed kinetic chain exercise experimental group (EGⅡ, n=10), and stretching control group (CG, n=10). Open and closed kinetic exercises lasted 30 minutes three times a week for six weeks and stretching exercises performed four actions for 20 seconds and five sets. The measurement tools using surface electromyography to measure muscle activity in the ankle joint. The dynamic balance of the ankle was evaluated using the Y-Balance test.
Results: Following the intervention, closed and open kinetic chain exercise group showed significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance (P<.05). However, no significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance between closed and open kinetic chain exercise group (P<.05).
Conclusion: This study provides evidence that closed and open kinetic chain exercise can be presented as an effective exercise for the muscle activity of ankle muscle and dynamic balance of the subject with chronic ankle instability.

INTRODUCTION
SUBJECTS AND METHODS
    Subjects
    Exercise method
    Measuring equipment and method
    Data analysis
RESULTS
    Comparison of the results of muscle activity pre- andpost-intervention in three group
    Comparison of the results of dynamic balance preandpost-intervention in three group
DISCUSSION
CONCLUSION

• Namjin Jung(Department of Physical Therapy, Kyungwoon University) Corresponding author