The maintenance of static and dynamic posture is depen4ant on normal function of muscle - bone - joint system (MBJ). In the other hand, the physiological function can be defected due to postural abnormalities. Kyphosis, or excessive curvature of the thoracic spine is one of the most prevalent spinal deformities. It seems that this deformaity in addition to a reduction of mechanical efficiency of the body, also has undesirable effects on the respiratory system. The purpose of the study was to investigate the kyphosis fluctuation and vital capacity following a corrective exercise program. Flexible ruler with reliability of 87% in comparison to X-ray technique measured the subjects, angle of kyphosis (n =364). 15 male students (aged between 16.47 and 1. O6yrs) were selected non - randomly to participate in the exercise . Digital spirometer measured the vital capacities of the subjects. Corrective exercise protocol for improving kyphosis was performed during the weeks / 3 sessions per week. The data were analyzed using t-student and the analysis regression. Corrective exercise program has s4gnificant effect on reduction of kyphosis’s degree and vital capacity (P? 0.05). There was a significant relationship in pre tests and post-tests between angle of kyphosis and vital capacity of the subjects (P?0. 05). Also, the results of the regression showed the relationship between degree of kyphosis and the vital capacity. The findings not only indicated the prevalence of kyphosis among students, it also emphasized the reliability and s4çnificance of applying feasible, accurate, available, and non - invasive methods of corrective exercise on improvement of postural deformities.
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