Maryam Mazidi
Amir Letafatkar
Maliheh Hadadnejad
Siavash Rajabi

Introduction: Muscular fatigue is a common phenomenon in daily sports activities and is worsening motor performance. The aim of this study was to determine the effect of neck muscular fatigue on static and dynamic postural control in elite male volleyball players. Methods: For this study, ۳۰ elite male athletes with mean age of ۲۳.۳±۳.۵ years old, height of ۱۸۴.۱±۷.۷ cm, and weight of ۷۶.۶±۳.۱ kg were selected in the available form and divided randomly into control and experimental groups. Fatigue protocol was induced on both sides via maximal exhausting protocol by instructing the subjects in experimental group to perform a "Dumbbell Shrug Trap Exercise" commonly used in fitness training to specifically involve Levator Scapulae and Trapezius superior muscles. The subjects’ dynamic and static postural control ımmediately after fatigue were assessed by Biodex System (level ۴ and ۳). For statistical analysis paired and sample t-test (α≤۰.۰۵) were used. Results: The results of this study showed that in the level ۴ of Biodex system there were significant differences in Ant-Post (P=۰.۰۳۰), Med-Lat (P=۰.۰۲۰), Limit of stability (P=۰.۰۱۲) and dynamic balance (P=۰.۰۱۱). In the level ۸ of Biodex system there were significant differences in Ant-Post (P=۰.۰۲۲), Med-Lat (P=۰.۰۲۰), Limit of stability (P=۰.۰۱۱) and dynamic balance (P=۰.۰۲۱). With respect to study results, there were significant differences in static balance(P=۰.۰۱۲) in experimental group but there were not significant differences in control group (P=۰.۲۱۴). Conclusion: Based on this study results, we concluded that neck muscle fatigue affects stability indexes, static and dynamic postural control so it seems that increasing the endurance of neck muscles to prevent early time fatigue, should be considered.

Static Postural Control, Dynamic Postural Control, Elite Volleyball Players, Static Postural Control, Dynamic Postural Control, Elite Volleyball Players