Impact of exercise on bone health and contraindication of oval contraceptive use in young women

Purpose: The effect of quantified resistance and high impact exercise train ing on bone mass as modified by age and oral contraceptive (OCont) use in y oung women was studied. Methods: Women were categorized by age (18-23 vs 24 -31 yr) and OCont use, and were then randomized into either three sessions of resistance exercise plus 60 min.wk(-1) of jumping rope or a control grou p for 24 months. Total body, spine, femoral neck, greater trochanter, Ward' s area, and radial bone mineral density (BMD) and/or content (BMC), biochem ical markers of bone turnover, dietary intake of calcium, lean body mass, m aximal oxygen uptake, and strength were determined at baseline and every 6 months. Results: Total body (TB) BMC percent change from baseline was highe r in exercisers compared with nonexercisers at 6 and 24 months. OCont users had lower bone turnover at baseline and a decrease in TBBMC from baseline compared with non-OCont users at 24 months. Spine BMC and BMD decreased in the exercise and OCont group at 6 months and remained significantly below n onexercisers who used oral contraceptives at 2 yr. Femoral neck BMD also de creased in the exercise and oral contraceptive group at 6 months. Conclusio ns: Exercise prevented a decline in TBBMC seen in the nonexercisers. On the other hand, exercise in oral contraceptive users prevented the increase ob served in the spine of the nonexercise plus OCont group.