Background: The ability to maintain body position in space is called postural control. Muscular fatigue created after doing voluntary repeated contractions impairs postural control. Thus, the present study was conducted to compare the effects of fatigue of the lumbar extensor muscles and duration of these effects on postural sway between soccer player and non-athlete participants. Methods: A total of 15 male soccer players and 15 male non-athletes participated in this cross- sectional study. Lumbar extensor fatigue is produced by a dynamometer and maintains 60% of the maximum voluntary isometric contraction in standing position. The mean velocity and the total area of the participants were evaluated using force plate at baseline, immediately, 3, 6, and 9 minutes after fatigue and compared between the 2 groups. Descriptive statistics, repeated measurement ANOVA, and independent t test were used for data analysis. Results: The results demonstrated that fatigue of the waist extensor muscles affects the postural sway (p= 0.001). Also, the total area level was recovered earlier than the mean velocity after fatigue. The results revealed that total area and velocity with eyes closed decreased in the soccer player group compared with the non-athlete group. Conclusion: Lumbar extensors fatigue significantly changed the mean velocity and the total area in soccer players and non-athletes. Lumbar fatigue had more effects on the total area than the mean velocity in the two groups.
Keywords: Athlete; Balance; Lumbar; Muscle fatigue; Postural control.