Low levels of vitamin D may reduce the muscle power and force in adolescent girls, according to a new study from the UK. The researchers from the University of Manchester report that the vitamin D levels of 99 adolescent girls between the ages of 12 and 14 was linked with muscle power and force. “We know vitamin D deficiency can weaken the muscular and skeletal systems, but until now, little was known about the relationship of vitamin D with muscle power and force,” said lead author of the study Kate Ward, PhD. “Our study found that vitamin D is positively related to muscle power, force, velocity and jump height in adolescent girls.”
The reseachers found that blood samples from the girls showed that the average vitamin D levels were 21.3 nanomoles per litre (nmol/L), and ranged from 2.5 to 88.5 nmol/L. While none of the girls had any physical symptoms of vitamin D deficiency, the researchers report that 75 per cent of the screened population had low active vitamin D levels (25(OH)D levels). Muscle strength and force were measured using a technique called jumping mechanography which derives power and force measurements from a subjects performance in a series of jumping activities. The researchers report that girls without vitamin D deficiency performed significantly better in the jumping-force test. The study is published in the February 2009 issue of the Journal of Clinical Endocrinology & Metabolism.