Background. Falls can be extremely detrimental to someone’s daily living, as well as life threatening This is especially true for individuals who have back problems, are sedentary, and have other health disorders. The purpose of this study was to investigate the effect of trunk extensor muscles fatigue on static postural control in young healthy adults compared to middle aged subjects. Methods. University students (n=10), and Middle-aged subjects (n=6; 40+ years of age) stood as immobile as possible on a force plate, with their feet together and eyes closed under two conditions; Fatigue and No fatigue. Fatigue was achieved through repetitive extensions of the trunk until a subjective fatigue level was reached. We measured center of pressure (CoP) displacements in the A/P and M/L planes using a force plate to assess standing balance. Findings. We did not observe any significant interaction between age and fatigue indicating that fatigue affected both age groups similarly. The CoP variability was higher for the middle aged compared to the young adults in both the fatigue and no-fatigue conditions. Interpretation. The results of this study indicate that trunk extensor fatigue does not affect balance differently for young compared to middle-aged subjects. This study also suggests that postural control decreases significantly with increasing age. Our finding that trunk extensor fatigue did not significantly affect the postural control of upright stance contradicts previous studies; this difference may be due to the subject sample in our study.