Date of Completion


Degree Type

Honors Thesis


Health & Human Sciences (HHSC)

First Advisor

William P. McCormack


Research has shown that weight-bearing physical activity such as running results in osteogenesis; distance runners, however, may experience deficiencies at specific sites. The purpose of this investigation was to examine changes in bone mineral density (BMD) of male and female collegiate cross-country runners over two years. Methods: BMD of 29 collegiate distance runners (16 men and 13 women) were measured five times over 24 months using dual-energy x- ray absorptiometry (DXA) at the anterior-posterior (AP) and lateral (LAT) spine, femoral neck (FN), total hip (TH), whole body (WB), and ultra-distal (UD) forearm. A repeated measures multivariate analysis of covariance, with bone free lean mass (BFLM) as covariate, was used to compare mean BMD values. Results: Adjusted for BFLM, there were no significant differences (p>0.05) in BMD at any site between sexes. There were no significant differences at the AP or LAT spine, or FN across visits for either sex. There was a significant increase in BMD (p=0.044) at the UD forearm over two years in males. However, 56% of the men (n=9) had a z-score <-1 at the UD forearm. Seven of 11 women had z-scores <-1.0 at the LAT spine and four of 13 had z-scores <-1.0 at the AP spine. Conclusion: There were no significant changes in BMD at any site over the two-year time frame, except the men had a significant increase in BMD at the non-dominant forearm. The spine appears to be an area of concern for the women in this study when examining z-score results.