Effects of ankle muscles fatigue on dynamic postural stability in healthy women athlete

The ability to maintain upright stance is essential in gait and initiation of voluntary movements that are vital not only for sport but also for activity of daily living. Lateral ankle sprains are common in athletes and are most prevalent in jumping sports such as volleyball, football and basketball. Although these injuries are common after direct contact. It may occur in non contact mechanism such as landing from a jump. Neuromuscular control plays a major role in dynamic joint stability. Most of ankle joint injuries occur in jump-landing task and at the end of sport activitiesparticularly when the athlete is fatigued. Our purpose was to evaluate the effects of ankle muscle fatigue on dynamic postural stability in jump landing task. Twenty two healthy women athletes (age:22.8±1.7 years, height:160.3±4.9 cm and weight:56.2±5.8 kg) volunteered to participate in this study. Two test sessions were done with a rest period of one week between them. During each session, effect of one group of ankle muscles (sagital or frontal movers) on dynamic postural stability was assessed. Postural stability was evaluated for 5 seconds after landing on force plate by postural stability indices (Medial/Lateral, Anterior/Posterior, Vertical and Dynamic Postural Stability Indices) before and after isokinetic fatigue of ankle muscles. The finding indicate significant increase in all stability indices after isokinetic fatigue of ankle muscles (p<0.05).These results indicate that isokinetic fatigue of ankle muscles significantly decrease postural control ability in healthy women athlete.