Problem statement: The proprioception information is a prerequisite for balance, body’s navigation system and the movement coordinator. The aim of this study was to investigate the effects of fatigue and chronic ankle instability on dynamic postural control. Approach: Thirty physical education students (14 males, 16 females) in two groups (15 healthy age = 21.78±0.79 years, height = 168.3±5.6 cm and weight = 63.6±2.6 kg, 15 with chronic ankle instability age = 21.43±0.83 years, height = 168.4±5.5 cm and weight = 63.3±3.2 kg) participated in this study voluntary. Star Excursion Balance Test was used for evaluation of dynamic postural control. Subjects performed a functional fatigued protocol that lasted 15 min. Using the Borg scale, also measured rating of perceived exertion before, middle and after the fatigue protocol. Results: The findings indicated that dynamic postural control decreased after fatigue in two groups (p<0.05). In contrast, there was only significance different between two groups after fatigue in lateral and antrolateral directions of Star Excursion Balance Test (p<0.05). Conclusion: Fatigue and chronic ankle instability can effect on dynamic postural control also, combination fatigue and chronic ankle instability can increase this effect. High incidence of ankle sprains especially in lateral and antrolateral directions which lead to reducing of balance can be practical guideline for training programs and management of fatigue in athletes. This finding also helps to sport physiotherapists to more emphasis on ankle sprain in rehabilitations on lateral and antrolateral directions.
