Studies in young women show that rowing exercise is osteogenic at the spine. However, little is known regarding rowing exercise and spine bone mineral density in older women. The aim of this study was to examine differences in spine bone mineral density (BMD) and back strength between premenopausal and postmenopausal competitive female masters rowers (n=28, 45.5 ± 4.7 yrs, n=28, 56.1 ± 5.7 years, respectively) and age-matched non-rowers (n=30, 43.3 ± 4.2 yrs; n=26, 56.8 ± 4.8 years). Competitive rowers were recruited from nine rowing clubs in the local area and compared to controls recruited from the same region who were normally active but not participating in rowing activity. Participating rowers had been engaged in competitive rowing for a minimum of one year. The average years spent rowing for the premenopausal and postmenopausal groups was 7.5 ± 6.6 yrs and 5.9 ± 6.9 yrs, respectively. BMD (g/cm²) of the third lumbar vertebrae (L3) was measured by dual-energy x-ray absorptiometry (DXA) in both the anterior-posterior and lateral views. Back strength was assessed using a standing cable tensiometer. Subjects also completed questionnaires to assess diet, physical activity, medical history and rowing history. Differences in BMD and back strength between groups were determined by analysis of covariance, controlling for lean mass. Compared to controls, postmenopausal rowers had 3.2% higher BMD at the anterior-posterior spine (p=.02) and 4.4% higher lateral spine BMD (p=.04). Furthermore, isometric back strength was 22.6% greater in these rowers than controls (p=.01). In contrast, controls had higher lateral BMD than rowers, with no differences in AP spine BMD or back strength between the premenopausal rowers and controls. Back strength was a significant predictor of AP spine BMD in premenopasual rowers and controls (R²=0.137, p=0.004) and of lateral spine BMD in postmenopausal rowers only (R²=0.153, p=0.04). There were no differences in calcium intake, age, menopausal status, weight, or lean mass between rowers and controls in either the premenopausal or postmenopausal samples. Since both increased BMD and back strength are associated with reductions in vertebral fracture risk, our results suggest that rowing exercise may be an important strategy to promote bone health and reduce vertebral fracture risk in postmenopausal women. However, the forces applied in rowing may not be great enough to alter bone mass before the onset of menopause. Therefore more research is needed examining rowing exercise in these older populations. / Graduation date: 2005