Comparing bone mineral density (BMD) of spinal L2-L4 in Iranian swimmers and their foreign counterparts

It has been shown through various studies that athletes who compete in such non–weight-bearing sports as swimming typically show lower BMD in the lumbar spine and lower limb sites than those who are involved in weight-bearing sports. Gravitational forces produce a passive mechanical effect that plays a role in developing and maintaining of bone mass. This study was conducted with the aim of comparing the bone mineral density (BMD) of spinal L2-L4 in Iranian swimmers with that of their foreign counterparts. Twelve professional male swimmers (mean age 24±3. 3 yr, mean weight 81±1. 1 kg, and mean height 175±5. 2 cm) were compared with fourteen professional males foreign swimmers (mean age 22±3. 6 y, mean weight 72±10 kg, mean height 182±7. 2 cm). These subjects, all in good health, were randomly selected from the available population of athletes who had been involved in continuous swimming activities for past five years. BMD were measured on L2-L4 lumbar spines via dual-energy X-ray absorptiometry (DEXA). The data were analyzed through one –sample mean comparison and Pierson correlation. The results showed that the amount of BMD in Iranian swimmers (1. 02 ± 0. 04 g. cm²) was less than that of foreign swimmers (1. 16 ± 0. 16 g. cm²، (p=0. 000)). Considering the importance of BMD in lumbar spine for swimmers and its significant loss among Iranian swimmers compared to foreign swimmers, which was evident from the results obtained, it is necessary that swimming must be accompanied by weight-bearing exercises and a diet rich in dairy.