تاثیر اعمال بار خارجی بر روی ثبات وضعیتی افراد سالم و بیماران مبتلا به کمردرد مزمن غیراختصاصی

 Background: The purpose of this study was to identify the effects of external loads on balance control during upright stance in Chronic Low Back Pain (CLBP) patients and healthy adults. Methods: This study was a qausi-experimental design. External loads were applied to 23 young, healthy participants and 21 low back pain subjects, and effects on balance control were characterized by Center-of-Pressure (COP) based measures. Center COP data were used to calculate standard deviation of amplitude, standard deviation of velocity in anterior-posterior and medial-lateral directions, mean total velocity and phase plane parameters. We used two way ANOVA to explore the pre/post applying external load and the between groups difference.  Results: The results showed that applying external load had a significant main effect on the standard deviation of amplitude in anterior-posterior and medio-lateral direction and       parameters. There was no interaction of load and group in this study. Also there was no difference between two groups at the beginning of the test.  Conclusions: These data show that wearing 10 kg of external weight in a waistcoat increases the postural sway of subjects, which may in turn increase the likelihood of falls and injury.