Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 37 4 2015 10 01 The Effect of Trunk Extensor Muscles Exhaustion on Static Balance in Young Adult and Middle Aged Women 28 31 EN Mehrangiz Qorbani Roqaye Kansari Sara Mehdizade Jozani Amir Reza Sohrabi Journal Article 2014 02 04 2014 04 19 Background & Objectives: Falling happens during unrecovered balance in people. The purpose of this research was to investigation the effect of extensor muscles fatigue on static balance control in two groups of healthy young and middle aged women. Materials & Methods: In a group of young adult (23 ± 1.6 yrs) and middle aged women, the standing balance test was studied before and after fatigue in a double blind situation. To evaluation of the balance, center of pressure (COP) of each person was assessed in two directions of Anterior/Posterior and medial lateral on the force plate. Results: The studied groups were 10 young women (23 ± 1.6 yrs) and 6 middle aged women (51 ± 5.4 yrs), age didn’t have a Significant effect on the fatigue status. Middle aged women had higher COP variability before and after fatigue Conclusion: In conclusion postural sway is increased with age. The effect of trunk extensor muscles fatigue was not significant on balance.