the comparison of bone mineral density (bmd) of spinal l2-l4 iranian swimmers and foreign

background and aim: the researches show that athletes who compete in non–weight-bearing activities، such as swimming، typically show lower bmd in the lumbar spine and lower limb sites than athletes who perform weight-bearing activities. gravitational forces produce a passive mechanical effect that plays role in developing and maintaining of bone mass. the comparison on the bone mineral density (bmd) of spinal l2-l4 iranian swimmers with foreigners is the aim of this study. materials and methods :the participants of this study were twelve professional male swimmers with the average of age ( age 24±3.3 y ، weight 81±1.1 kg ،height 175±5.2 cm) in comparison with 14 professional males foreign swimmers with the average of age ( age 22±3.6 y ، weight 72±10 kg ، height 182±7.2 cm) . these athletes were randomly selected of persons who have done continuous swimming activities for five years and were in safe health. bmd were measured on l2-l4 lumbar spines by dual-energy x-ray absorptiometry (dexa) .the data were analyzed by means of statistical evaluation with one –sample mean comparison and pierson relation.   results : the results show that  the amount of  bmd  iranian  swimmers( 1.02 ± 0.04 g.cm²)  is less than foreign swimmers ( 1.16 ± 0.16 g.cm² ، (p=0.000) ). conclusion : the results showed that with considering the importance of bmd in spine lumbar on swimmers and significant decrease of bmd on iranian swimmers rather than foreign swimmers، it is necessary that swimming must be compensated with weight-bearing exercise in the land with rich nutrition consists of dairy production. key word : bone mineral density، dual-energy x-ray absorptiometry، lumbar spine، swimmer، osteoporosis