School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
Bone. 2010 Apr;46(4):1043-9. doi: 10.1016/j.bone.2009.12.001. Epub 2010 Jan 6.
Exercise can increase bone strength, but to be effective in reducing fracture risk, exercise must be feasible enough to be adopted into daily life and influence potentially vulnerable skeletal sites such as the superolateral cortex of the femoral neck, where thinning is associated with increased fracture risk. Brief, high-impact exercise increases femoral neck bone density but the optimal frequency of such exercise and the location of bone accrual is unknown. This study thus examined (1) the effectiveness of different weekly frequencies of exercise on femoral neck BMD and (2) whether BMD change differed between hip sites using a high-impact, unilateral intervention.
Healthy premenopausal women were randomly assigned to exercise 0, 2, 4, or 7 days/week for 6 months. The exercise intervention incorporated 50 multidirectional hops on one randomly selected leg. BMD was measured by DXA at baseline and after 6 months of exercise. Changes in the exercise leg were compared between groups using ANCOVA, with change in the control leg and baseline BMD as covariates. RM-MANOVA was conducted to determine whether bone changes from exercise differed between hip sites.
61 women (age 33.6+/-11.1 years) completed the intervention. Compliance amongst exercisers was 86.7+/-10.6%. Peak ground reaction forces during exercise increased from 2.5 to 2.8 times body weight. The change in femoral neck BMD in the exercise limb (adjusted for change in the control limb and baseline BMD) differed between groups (p=0.015), being -0.3% (-1.2 to 0.6), 0.0% (-1.0 to 1.0), 0.9% (-0.1 to 2.0) and 1.8% (0.8 to 2.8) in those exercising 0, 2, 4 and 7 days per week, respectively. When BMD changes at upper neck, lower neck and trochanter were compared using RM-MANOVA, a significant exercise effect was observed (p=0.048), but this did not differ significantly between sites (p=0.439) despite greatest mean increases at the upper femoral neck.
Brief, daily hopping exercises increased femoral neck BMD in premenopausal women but less frequent exercise was not effective. Brief high-impact exercise may have a role in reducing hip fragility, but may need to be performed frequently for optimal response.
运动可以增加骨强度，但要降低骨折风险，运动必须足够可行，才能融入日常生活，并影响到潜在脆弱的骨骼部位，如股骨颈的外侧皮质，该处变薄与骨折风险增加有关。短暂的高强度运动可以增加股骨颈的骨密度，但这种运动的最佳频率和骨量增加的部位尚不清楚。因此，本研究检测了（1）不同周运动频率对股骨颈骨密度的影响，（2）使用高强度单侧干预时，骨密度变化在髋部不同部位是否存在差异。
健康的绝经前妇女被随机分配每周运动 0、2、4 或 7 天，持续 6 个月。运动干预包括在随机选择的一条腿上进行 50 次多方向跳跃。在基线和 6 个月的运动后，使用 DXA 测量骨密度。使用协方差分析（ANCOVA）比较各组间运动腿的变化，以对照组腿和基线骨密度为协变量。采用重复测量方差分析（RM-MANOVA）确定来自运动的骨变化是否在髋部不同部位存在差异。
61 名女性（年龄 33.6±11.1 岁）完成了干预。锻炼者的依从性为 86.7±10.6%。运动时的最大地面反作用力从 2.5 倍体重增加到 2.8 倍体重。运动肢体的股骨颈骨密度变化（校正对照组肢体和基线骨密度的变化）在组间存在差异（p=0.015），分别为-0.3%（-1.2 至 0.6）、0.0%（-1.0 至 1.0）、0.9%（-0.1 至 2.0）和 1.8%（0.8 至 2.8）。当使用 RM-MANOVA 比较颈上部、颈下部和转子间的骨密度变化时，观察到运动的显著效果（p=0.048），但各部位之间的差异无统计学意义（p=0.439），尽管股骨颈上部的平均增加幅度最大。
短暂的每日跳跃运动增加了绝经前妇女的股骨颈骨密度，但较少的运动频率没有效果。短暂的高强度运动可能在减少髋部脆弱性方面发挥作用，但为了达到最佳效果，可能需要频繁进行运动。
