Effect of low repetition jump training on BMD in middle-aged women

本研究的假设是，低重复、高冲击的垂直跳跃训练，2-3次/周，将有效地提高/维持骨密度（BMD）的普通中年妇女。选择41名每周游泳2-3次的绝经后中年妇女，平均年龄（59.9±5.9）岁，身高（155.4±3.8）cm，体重（52.1±7.0）kg。训练开始12个月后，采用双能X线骨密度仪进行第二次骨密度测量。28名受试者（每组14名受试者）完成了所有测量。非配对Student t检验显示，两组之间腰椎（L2-L4）、股骨近端和股骨颈区域的BMD百分比没有显著变化。虽然两组之间没有显著差异，但跳跃训练组的BMD百分比变化的平均值更大，接近100%，与对照组相比。两组无显著性差异的原因之一可能是跳跃训练（1.5次/周）依从性差。因此，选择跳跃训练依从性相对较高的受试者（n=5和1.8次/周），其股骨近端（99.8± 5.0vs94.9 ±5.9%）和股骨颈区（100.2± 5.5vs93.7 ±5.9%）的BMD百分比变化均显著高于对照组。我们的结论是，低重复和高冲击的训练可能是有效的，特别是近端股骨区域的绝经后妇女。高依从性的跳跃训练，理想的2-3次/周将需要导致更明显的训练效果，我们希望跳跃训练可能有助于保持老年人的骨骼健康的运动处方，即使在绝经后。

The hypothesis of the present study was that low-repetition and high impact training of vertical jump, 2-3 times/week would be effective for improving/maintenance bone mineral density (BMD) in ordinary middle-aged women. Forty-one middle-aged postmenopausal women who swim 2-3 times/week at swimming club, with mean age, height and weight of 59.9±5.9 years, 155.4±3.8 cm and 52.1±7.0 kg, respectively, were divided into two groups; jump training and a control group. After 12 months of the jump training started, the second BMD measurement, by dual energy X-ray absorptiometry, were performed. Twenty-eight subjects (14 subjects in each groups) completed all measurements. The unpaired student t-test reviled that there was no significant BMD percent change in lumbar spine (L2-L4), total proximal femur, and femoral neck region between the two groups. Although there was no significant difference between two groups, the average values of BMD percent change in the jump training group was greater and close to 100%, compared to the control group. One of the reasons for no significant difference was found between two groups, would be the poor compliance of jump training (1.5 times/week). So that the subjects who had relatively high compliance of jump training (n=5 and 1.8 times/week) were selected and this group showed significantly higher BMD percent change in total proximal femur (99.8±5.0 vs 94.9±5.9%) and femoral neck region (100.2±5.5 vs 93.7±5.9%) than the control group. We concluded that low-repetition and high impact training may be effective especially proximal femur region for postmenopausal women. High compliance of jump training that ideally 2-3 times/week would be required to lead the training effects more clearly, and we expect that jump training may help the exercise prescription of keeping bone health for elderly people, even after menopause.