The effect of erector spine muscles fatigue on balance compensation in kyphotic subjects after postural perturbations in sagital plane

Introduction: Postural control is the ability to maintain upper extremities and different parts of body during static and dynamic status in proper biomechanical alignment. Fatigue is one of the factors that can affect the posture. Muscle fatigue can reduce sensory input to the brain and finally decrease the balance. The aim of this study was to investigate the effect of erector spine muscles fatigue on balance compensation in kyphotic subjects after postural perturbations in the sagital plane.Materials and Methods: Twelve male college student with spinal curvature of more than forthy degrees (mean ± SD age; 23.25 ± 1.42 years, mean ± SD height; 174.92 ± 6.89 cm, mean ± SD weight; 67.33 ± 12.17 kg) and twelve male college student with normal curvature of the dorsal spine (mean ± SD age; 23.17 ± 1.53 years, mean ± SD height; 178.92 ± 6.16 cm, mean ± SD weight; 71.75 ± 9.34 kg) were participated in the study. They agreed and signed the consent form. A flexible ruler was used to measure thoracic kyphosis. To assessment the balance the center of pressure (COP) displacement after sudden perturbation (by releasing a weight equivalent to 10% of the subjects that has been attached to the Foot Scan) in the anterior–posterior direction were measured by Foot Scan. Experimental procedure was measured before and just after the fatigue protocol. ANOVAs and independent t-test were performed to data analyses.Results: The results indicated no significant differences of the COP displacement in both kyphotic (P = 0.678) and control (P = 0.685) groups. Our results showed that erector spine muscles fatigue could not affect the postural. Conclusion: Possibly compensation of posture after balance perturbation can not affected by erector spine muscles fatigue. Keywords: Postural perturbation, Center of pressure, Anterior- posterior, Local Fatigue, Balance, Erector spine, Kyphosis