A WEIGHTED VEST TO PREVENT LEG WEAKNESS AND OSTEOPOROSIS

该项目将包括一项为期2年的干预发展研究 (IDS)随后进行为期3年的干预研究（IS）。 整体 该项目的目的是测试是否穿着加重背心， 预防肌肉无力和骨质疏松症。 首先，IDS将 进行，以进一步完善背心剂量，并评估是否 可以测量通过背心使用的骨负荷的生物力学近似值。 第二，将进行随机对照试验， 背心对肌肉力量和骨密度的影响。 尼龙背心最大重量可达12公斤，并规定 体重百分比（%BW）。 受试者在日常活动中穿着背心 每天2小时的日常活动（如家务，散步），每天4天， 周 不需要额外的特定体力活动处方。 IDS将包括27周、3组（对照、3%BW、5%BW）的术前和术后 在60例受试者中进行的一项研究，比较这些剂量对膝关节的影响 伸肌力量、副作用和附着力。 之前的背心研究 表明5%BW是该人群的最大耐受量;因此， IS选择最大和1/2最大剂量。 剂量为 将根据以下各项的影响决定RCT：膝关节伸肌 强度;安全性;和坚持性。 IDS将评估髋关节的拟议生物力学测量值是否 载荷、髋关节反作用力和髋关节力矩，随 背心使用。 每个背心剂量对以下方面的影响：1）骨转换 指标; 2）步态和平衡; 3）自我报告的功能状态， 将评估观察到的身体表现。 坚持使用背心 干预结束后3个月和6个月， 考察 IS将包括一项为期24个月的单盲、双组随机化研究， 在66名受试者中进行对照试验。 它将检查一剂药物的效果 与注意力控制相比， 组：1）全髋骨密度; 2）量和时间过程中， 等速膝伸肌力量的变化;和3）长期安全性 并坚持使用背心。 如果IDS成功地 量化髋关节负荷的假设生物力学测量， RCT的第四个主要目标是评估 生物力学测量来预测BMD的变化， 背心实现骨向性的机制。 RCT的次要目标包括测量背心的影响 用于：脊柱BMD;全身钙;身体成分;骨转换 标记;步态和平衡;功能状态;和身体表现。

This project will consist of a 2-year intervention development study (IDS) followed by a 3-year intervention study (IS). The overall objective of the project is to test whether wearing a weighted vest can prevent muscular weakness and osteoporosis. First, an IDS will be conducted to further refine the vest dose and to assess whether biomechanical approximations of bone loading by vest use can be measured. Second, a randomized controlled trial will be conducted to test the effect of the vest on muscular strength and bone mineral density. The nylon vest can be weighted to a maximum of 12 kg and is prescribed as a percent of body weight (%BW). Subjects wear the vest during routine daily activities (eg, chores, walks) for 2 hours per day, 4 days per week. No additional specific physical activity prescription is required. The IDS will consist of a 27-week, 3-armed (control, 3%BW, 5%BW) pre-post study in 60 subjects to compare the effects of these doses on knee extensor strength, side-effects, and adherence. Prior vest studies suggest that 5%BW is the maximum tolerated in this population; thus, maximum and 1/2 maximum dose are selected for the IS. The dose for the RCT will be decided based on the effect of each on: knee extensor strength; safety; and adherence. The IDS will evaluate whether proposed biomechanical measures of hip loading, hip joint reaction forces and hip moments-of-force, change with vest use. The effects of each vest dose on: 1) bone turnover indicators; 2) gait and balance; 3) self-reported functional status and observed physical performance will be assessed. Adherence to vest use 3 and 6 months after the termination of the intervention will also be examined. The IS will consist of a 24-month, single blinded, two armed randomized controlled trial in 66 subjects. It will examine the effects of one dose of the vest (determined by the IDS) compared to an attention control group on the following: 1) total hip BMD; 2) amount and time course of change in isokinetic knee extensor strength; and 3) long-term safety of and adherence to vest use. If the IDS has been successful in quantifying the postulated biomechanical measures of hip loading, a fourth primary objective of the RCT will be to assess the ability of the biomechanical measures to predict changes in BMD, to explore the mechanism by which the vest accomplishes bone tropism. The secondary RCT objectives include measurement of the effect of vest use on: spinal BMD; total body calcium; body composition; bone turnover markers; gait and balance; functional status; and physical performance.