A comparison of bone mineral densities among female athletes in impact loading and active loading sports

The purpose of this study was to compare bone mineral densities (BMD) of collegiate female athletes who compete in impact loading sports; volleyball players (N = 8) and gymnasts (N = 13), to a group of athletes who participate in an active loading sport; swimmers (N = 7), and a group of controls (N = 17). All of the volleyball, swimming, and control subjects were eumenorrheic (10-12 cycles/year), whereas two of the gymnasts were amenorrheic (0-3 cycles/year), eight were oligomenorrheic (4-8 cycles/year), and three were eumenorrheic (10-12 cycles/year). Lumbar spine, proximal femur, and total body BMD were measured with dual-energy X-ray absorptiometry. The groups were compared with respect to the following regions: lumbar spine (L1-4); femoral neck; Ward's triangle; right and left arms; right and left legs; pelvis; and torso. When controlling for differences in height and weight the impact loading group (volleyball and gymnastic) had significantly greater BMD at the lumbar spine, femoral neck, Ward's Triangle, and total body when compared to the active loading (swimming) and control groups. The regional analysis from the total body scan revealed that the gymnasts had significantly (p < 0.05) greater BMD than all other groups at the right and left arm sites. The impact loading groups (gymnastic and volleyball) had a greater BMD in the legs and pelvis than the active loading (swimming) and control groups. Furthermore, the impact loading group had a greater torso BMD than the control group. There were no differences at any site between the active loading group (swimming) and control groups. Athletes who participated in impact loading sports (volleyball and gymnastics) had higher BMD than athletes in active loading sports (swimming). This difference appeared to be site specific. Furthermore, the prevalence of oligo/amenorrhea infthe gymnastic group did not appear to negatively influence BMD.