title: Effects of resistance training with and without caloric restriction on physical function and mobility in overweight and obese older adults: a randomized controlled trial.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Nicklas
authors.affiliation: 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.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Chmelo
authors.affiliation: 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.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Delbono
authors.affiliation: 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.
authors.forename: J Jeffrey
authors.initials: JJ
authors.lastname: Carr
authors.affiliation: 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.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Lyles
authors.affiliation: 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.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Marsh
mesh_terms: D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D031204:Caloric Restriction; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D009765:Obesity / Q000628:therapy*; D050177:Overweight / Q000628:therapy*; D055070:Resistance Training; D015431:Weight Loss / Q000502:physiology
keywords: body composition; caloric restriction; intermuscular thigh fat; muscle quality; muscle strength and power; obesity; older adults; resistance training; weight loss