Nicklas Barbara J, Chmelo Elizabeth, Delbono Osvaldo, Carr J Jeffrey, Lyles Mary F, Marsh Anthony P
From the Section on Gerontology and Geriatric Medicine, Department of Internal Medicine (BJN, EC, OD, and MFL), the Department of Radiology, Wake Forest School of Medicine (JJC), and the Department of Health and, Exercise Science (BJN and APM), Wake Forest University, Winston-Salem, NC.
Am J Clin Nutr. 2015 May;101(5):991-9. doi: 10.3945/ajcn.114.105270. Epub 2015 Mar 11.
Resistance training (RT) improves muscle strength and overall physical function in older adults. RT may be particularly important in the obese elderly who have compromised muscle function. Whether caloric restriction (CR) acts synergistically with RT to enhance function is unknown.
As the primary goal of the Improving Muscle for Functional Independence Trial (I'M FIT), we determined the effects of adding CR for weight loss on muscle and physical function responses to RT in older overweight and obese adults.
I'M FIT was a 5-mo trial in 126 older (65-79 y) overweight and obese men and women who were randomly assigned to a progressive, 3-d/wk, moderate-intensity RT intervention with a weight-loss intervention (RT+CR) or without a weight-loss intervention (RT). The primary outcome was maximal knee extensor strength; secondary outcomes were muscle power and quality, overall physical function, and total body and thigh compositions.
Body mass decreased in the RT+CR group but not in the RT group. Fat mass, percentage of fat, and all thigh fat volumes decreased in both groups, but only the RT+CR group lost lean mass. Adjusted postintervention body- and thigh-composition measures were all lower with RT+CR except intermuscular adipose tissue (IMAT). Knee strength, power, and quality and the 4-m gait speed increased similarly in both groups. Adjusted postintervention means for a 400-m walk time and self-reported disability were better with RT+CR with no group differences in other functional measures, including knee strength. Participants with a lower percentage of fat and IMAT at baseline exhibited a greater improvement in the 400-m walk and knee strength and power.
RT improved body composition (including reducing IMAT) and muscle strength and physical function in obese elderly, but those with higher initial adiposity experienced less improvement. The addition of CR during RT improves mobility and does not compromise other functional adaptations to RT. These findings support the incorporation of RT into obesity treatments for this population regardless of whether CR is part of the treatment. This trial was registered at clinicaltrials.gov as NCT01049698.
阻力训练（RT）可改善老年人的肌肉力量和整体身体功能。RT对于肌肉功能受损的肥胖老年人可能尤为重要。热量限制（CR）是否与RT协同作用以增强功能尚不清楚。
作为改善肌肉功能独立性试验（I'M FIT）的主要目标，我们确定了在老年超重和肥胖成年人中，增加CR以减轻体重对RT的肌肉和身体功能反应的影响。
I'M FIT是一项为期5个月的试验，纳入了126名年龄在65 - 79岁的超重和肥胖男性及女性，他们被随机分配到每周进行3天、中等强度的渐进性RT干预组，其中一组接受减肥干预（RT + CR），另一组不接受减肥干预（RT）。主要结局是最大膝关节伸肌力量；次要结局包括肌肉力量和质量、整体身体功能以及全身和大腿成分。
RT + CR组体重下降，而RT组体重未下降。两组的脂肪量、脂肪百分比和所有大腿脂肪体积均下降，但只有RT + CR组的去脂体重减少。干预后调整后的身体和大腿成分测量值，除肌间脂肪组织（IMAT）外，RT + CR组均较低。两组的膝关节力量、功率和质量以及4米步速均有相似程度的增加。RT + CR组干预后调整后的400米步行时间和自我报告的残疾情况均值更好，在包括膝关节力量在内的其他功能指标上两组无差异。基线时脂肪和IMAT百分比较低的参与者在400米步行以及膝关节力量和功率方面改善更大。
RT改善了肥胖老年人的身体成分（包括减少IMAT）、肌肉力量和身体功能，但初始肥胖程度较高者改善较少。在RT期间添加CR可改善活动能力，且不影响对RT的其他功能适应性。这些发现支持将RT纳入该人群的肥胖治疗中，无论CR是否作为治疗的一部分。该试验已在clinicaltrials.gov注册，注册号为NCT01049698。
