Improving Muscle for Functional Independence Trial
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      Aging is associated with declines in muscle strength, power, and overall functional ability
      that lead to disability and loss of independence. Furthermore, the existing high prevalence
      of obesity in the elderly is greatly exacerbating these aging-related declines in function.
      To date, regular exercise, especially resistance exercise, is the only known treatment to
      consistently improve muscle function and perhaps delay the onset of disability. However, not
      all individuals experience the same magnitude of benefit from a given exercise stimulus, and
      accumulating data show that obesity limits muscle adaptations to chronic exercise.Therefore,
      the proposed study is designed to determine the effects of caloric restriction on
      improvements in skeletal muscle function in response to RT.
    

Detailed description: 
      Design Overview:

      This is a 5-month randomized trial in 130 older, overweight or obese, sedentary men and
      women. Phase 1 involves recruitment and screening followed by baseline research testing
      (Phase 2). Next, subjects will be randomly assigned to one of two 5-month treatments (Phase
      3): RT intervention alone (RT) or to an RT with caloric restriction (RT+CR) intervention.
      Subjects will return for visits the completion of their 5 month intervention. A subset of
      participants (n=30) will return for an 18 month follow up.

      Interventions:

      Resistance training+ Caloric Restriction:Participants assigned to RT+CR group will be
      instructed to follow a hypocaloric diet (-600 kcal/d) for 20 weeks, as well as the resistance
      training program noted below.In addition, all participants will be provided with a daily
      calcium (1200 mg/d) and vitamin D (800 IU/d) supplement.The intervention will incorporate
      meal replacements, nutrition education, and lifestyle behavior modifications.

      Resistance training: The maximal weight that can be lifted with correct form in a single
      repetition (1RM) will be used to prescribe intensity. Strength testing will be repeated every
      4 wks and the training loads adjusted so that they are consistent with the 70% 1RM goal.
      Participants will exercise 3 d/wk on Nautilus resistance machines, under the supervision of
      two exercise leaders who are trained in basic life support and in emergency management
      procedures. All exercise will take place at Wake Forest University's Department of Health and
      Exercise Science Clinical Research Center (CRC). Participants will exercise in small groups
      which will allow a rotation/rest between machines and enhance the social environment. Heart
      rate and blood pressure will be measured before and after each session. Subjects will warm-up
      by walking or cycling for 5 minutes at a slow pace followed by large muscle flexibility
      exercises. The interventionists will ensure that participants adjust the equipment
      appropriate to their body size and complete the exercises with correct form. Training
      sessions will end with a cool-down by walking or cycling for 5 minutes at a slow pace
      followed by light stretching.
    

Intervention name(s): Resistance Training; Resistance Training + Diet
Intervention type(s): Behavioral; Behavioral
Intervention description(s): 3 d/wk resistance training; 3 d/w resistance training plus 600 kcal/d deficit
Other intervention name(s): RT; Nautilus resistance machines; RT+CR
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Obesity; Overweight; Older adults; resistance training; exercise