Limited evidence suggests that physical activity may prevent frailty and associated negative outcomes in older adults. Definitive data from large long-term randomized trials are lacking.

To determine whether a long-term, structured, moderate-intensity physical activity program is associated with a lower risk for frailty and whether frailty status alters the effect of physical activity on the reduction in major mobility disability (MMD) risk.

Multicenter, single-blind, randomized trial.

8 centers in the United States.

1635 community-dwelling adults, aged 70 to 89 years, with functional limitations.

A structured, moderate-intensity physical activity program incorporating aerobic, resistance, and flexibility activities or a health education program consisting of workshops and stretching exercises.

Frailty, as defined by the SOF (Study of Osteoporotic Fractures) index, at baseline and 6, 12, and 24 months, and MMD, defined as the inability to walk 400 m, for up to 3.5 years.

Over 24 months of follow-up, the risk for frailty (n = 1623) was not statistically significantly different in the physical activity versus the health education group (adjusted prevalence difference, −0.021 [95% CI, −0.049 to 0.007]). Among the 3 criteria of the SOF index, the physical activity intervention was associated with improvement in the inability to rise from a chair (adjusted prevalence difference, −0.050 [CI, −0.081 to −0.020]). Baseline frailty status did not modify the effect of physical activity on reducing incident MMD (P for interaction = 0.91).

Frailty status was neither an entry criterion nor a randomization stratum.

A structured, moderate-intensity physical activity program was not associated with a reduced risk for frailty over 2 years among sedentary, community-dwelling older adults. The beneficial effect of physical activity on the incidence of MMD did not differ between frail and nonfrail participants.

National Institute on Aging, National Institutes of Health.

有限的证据表明，体育锻炼可以预防老年人的虚弱和相关的负面结果。缺乏大型长期随机试验的确切数据。

要确定长期，有条理，中等强度的体育锻炼计划是否与较低的虚弱风险相关联，以及虚弱的状况是否会改变体育活动对减少主要行动不便（MMD）风险的影响。

多中心，单盲，随机试验。

美国有8个中心。

1635名社区居住的成年人，年龄在70至89岁之间，具有功能限制。

结构化，强度适中的体育锻炼计划，包括有氧，抵抗和柔韧性运动，或由讲习班和伸展运动组成的健康教育计划。

在基线，第6、12和24个月，由SOF（骨质疏松性骨折研究）指数定义的虚弱，以及MMD（定义为在长达3.5年的时间内无法行走400 m）。

在24个月的随访中， 与健康教育组相比，体育锻炼中的虚弱风险（n = 1623）差异无统计学意义（校正后患病率差异为-0.021 [95％CI，-0.049至0.007]）。在SOF指数的3个标准中，体育锻炼干预与无法从椅子上抬起的能力有所改善（调整后患病率差异为-0.050 [CI，-0.081至-0.020]）。基线虚弱状态并没有改变体育锻炼对降低入射MMD的影响（相互作用的P = 0.91）。

脆弱状态既不是进入标准，也不是随机分层。

有组织的中等强度的体育锻炼计划与久坐且居住在社区中的老年人在2年内降低体弱的风险没有关系。体力活动对MMD发生率的有益影响在体弱和非体弱的参与者之间没有差异。

美国国家老龄研究所，美国国立卫生研究院。