Osteoporosis is a significant public health problem for individuals over age 50 (55% are at risk), particularly for women. A key preventive strategy is increasing peak bone mass in youth. Limited information exists on the role that competitive sport activities can play in developing bone mass. Volleyball is a popular sport for girls and involves high impact activity and plyometric training. The purpose of the study was to compare bone mineral density (BMD) between high school and college competitive volleyball players to age matched controls. Relationships between BMD and age, and years of competitive play were also analyzed. The calcium intake, and time spent jumping in practice (volleyball players only) for each group were also assessed. Subject inclusion criteria were: no eating disorders, not amenorrhoeic, did not use calcium supplements (doctor recommended). The volleyball players followed the criteria above and played volleyball >7 months in a year. Subjects were 13 high school volleyball players (HSVB), 10 high school non-athletes (HSN), and 13 college volleyball players (CVB), and 13 college nonathlees (CN). The mean (+ SD) age, weight, body fat percentage, calcium intake, and years of competitive volleyball for the HSVB players were 16.2 + 1.3 yr, 67.5 + 8.0 kg, 27.2 ± 5.3 %, 1269.7 ± 581.7 mg, and 7.2 ± 1.2 yr. and for the CVB players were 19.5 + 1.0 yr, 74.2 ± 9.2 kg, 28.4 ± 4.7 %, 1059.6 ± 462.2 mg, and 8.5 ± 2.3 yr. respectively. The mean (+SD) age, weight, body fat percentage, and calcium intake for the HSN 16.2 ± 1.3 yr, 66.8 ± 12.4 kg, 34.7 + 6.1 %, and 857.9 + 469.5 mg and for the CN were 19.5 ± 1.0 yr, 73.9 + 9.1 kg, 40.1 + 4.4 %, and 1216.4 + 551.9 mg. Dual energy x-ray absorptiometry (DEXA) was used to determine the body composition and BMD at the following regions: AP spine, dual femur, and total body. The only significant descriptive difference was in percent body fat (P>0.05-0.01). The significant difference (P>0.01) between the athletes and non-athletes occurred in the AP spine (1.38 + 0.1 g.cm-2 and 1.20 ± 0.1 g•cm-2), dual femur (1.22 + 0.1 g•cm 2 and 1.05 ± 0.1 g•cm-2), and total body measurements (1.26 ± 0.1 g•cm 2 and 1.16 ± 0.1 ?cm-2). The athleticism and age was not significant for the BMD in the AP spine, total body, and dual femur. Likewise, the correlations between years playing volleyball and jumping in practice were not significant. The correlation between calcium intake in volleyball players and non-athletes showed no significant difference. In conclusion BMD is higher in volleyball players compared to non-athletes however there was no difference between the college and high school volleyball players. / School of Physical Education, Sport, and Exercise Science