Background and Aim: Fatigue is a factor that disrupts balance and leads to sport injuries. Female athletes have a much higher incidence of ligament injuries than men. The purpose of this study was to assess the effect of gender and functional fatigue on dynamic balance.

Materials and Methods: Thirty two non athletic healthy subjects (16 women and 16 men) aged between 18-35 year participated in this study. Star excursion balance test was performed pre and post functional fatigue at the posterolateral and posteromedial directions.

Results: Main effect of fatigue was significant (F=37.62, P<0.01). Both groups showed reduced reach distance after fatigue in posterolateral and posteromedial directions. Fatigue and group Interaction was not significant (F=0.045, P>0.05). The Interaction of fatigue and directions of star excursion balance test was not significant (F=1.169, P>0.05).

Conclusion: Fatigue reduced the dynamic postural control in both gender. However, this reduction was not different between the groups. It seems that other factors rather than the effect of fatigue on postural control contribute to the difference in the risk of injury between men and women.

Keywords: Functional fatigue, Balance, Gender

Background and Aim: Whole body vibration (WBV) is a new therapeutic modality which improves muscle function, proprioception and postural control by creating an oscillatory mechanical stimulation. The aim of this research was to investigate the immediate effect of WBV on postural control in young adults.

Materials and Methods: In this quasi-experimental study, 22 healthy subjects were participated as a single group. Non-probability simple sampling method was used. Subjects were treated with 4 minutes WBV bout. The subjects repeated four times a 60-s light exercise program according to instructions which was shown by the therapist. During the vibration intervention, the vibration frequency increased in 1 minute intervals from 15 Hz for the first minute to 30 Hz for the last minute. Postural control indexes were recorded using the Biodex Balance system in situations of two leg standing with open and close eyes that included overall stability index (OSI), anterior-posterior stability index (APSI), medial-lateral stability index (MLSI) . In order to analyze the data, paired t-test was used.

Results: The results indicated that in the case of standing on two legs with eyes open, OSI and MLSI were statistically significant (P = 0.02; P = 0.01, respectively) and with eyes closed, OSI, APSI and MLSI were statistically significant (P = 0.000; P = 0.001; P = 0. 001, respectively).

Conclusion: Four minutes WBV bout can induce improvement of postural control and balance in young adults.

Keywords: Whole body vibration, Balance, Young adults, Stability