The effect of swimming and type of stroke on bone metabolism in competitive adolescent swimmers: a pilot study

Background/aim: Physical activity plays a key role in increasing and preserving bone mineral density (BMD). Effects on bone development associated with various nonweight-bearing sporting activities, such as swimming, are controversial. Different strokes used in swimming may also present as another factor. The aim of this study was to evaluate the effect of swimming and type of stroke on BMD in competitive adolescent athletes. Materials and methods: Seventy-nine swimmers between the ages of 10 and 21 years participated in this study. BMD was measured with dual-energy X-ray absorptiometry at the lumbar vertebrae and left proximal femur. Daily calorie intake and calcium consumption, and measurements of calcium, phosphorus, alkaline phosphates, 25-hydroxyvitamin D (25(OH) D), and osteocalcin were evaluated. Results: Preliminary results revealed that the type of stroke had no effect on BMD (P = 0.79). Additionally competitive swimmers did not have augmented bone mineral accretion, and in 13.9% of athletes low BMD was confirmed. Sixty percent of swimmers had either deficient or insufficient 25(OH) D levels and a low mean calorie (P = 0.542) and calcium (P = 0.038) intake was observed. Conclusion: This was the first study to evaluate the effect of swimming stroke on BMD. Although no effect was statistically shown, further studies with a larger series may determine this effect.