Effect of Exercise Intensity on Vitamin D

Inclusion Criteria: * all subjects were trainable and able to walk freely without assistance. * Had vitamin D deficiency, the serum level of 25-hydroxyvitamin D (25(OH) D) was ranged from 10-20ng/mL. * Did not take calcium or vitamin D3 supplements, medications for osteoporosis, antiepileptic drugs, or any medications that may affect the vitamin D metabolism in the last 5 months. * The feeding method during the first two years of age for all children was bottle feeding. * Mild to moderate mentally retarded, (IQ ranged from 45-70) to be able to understand and obey simple orders. * free from any medical consequences for example cardiopulmonary disorders, auditory defects, and visual impairments. * Had no previous history of strength training. * Body mass index percentile ranged from the 50th percentile to less than the 75th percentile (healthy). * The feeding method was by mouth with no special diet, with an absence of signs of malnutrition Exclusion Criteria: * autoimmune disease. * Renal diseases. * Have taken any thyroid medications. * Obesity. * epileptic fits.