Influence of Muscle Strength on the Energy Cost of Walking in Obese Subjects
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      The purpose of this study is to evaluate the efficacy of 2 physical exercise training
      programs, with a supplementation in fruits and vegetables, on energy cost of walking. 60
      subjects will be randomized into 2 groups. The first program will be consist of an interval
      strength training for 30 min on bicycle ergometer (which include strengthening exercises in
      an high intensity interval training). The second program will be conducted at a relatively
      low intensity of effort, corresponding to 50% of oxygen uptake (VO2) peak measured by
      indirect calorimetry. All subjects will receive a free supplement of 5 fruits and vegetables
      per day during all the intervention. The intervention will last 9 months in total : 5 month
      at the hospital fallow by 4 month at home.
    

Detailed description: 
      Background: in Reunion Island in 2000, the REDIA study showed a prevalence of obesity among
      women and men of 20% and 10%, respectively. Obesity is associated with several diseases,
      including diabetes mellitus, hypertension, dyslipidaemia and ischaemic heart diseases.
      Regular physical activity associated with a hypocaloric diet and an intake of fruits and
      vegetables can reduce body fat mass and obesity-associated complications. However there is no
      consensus on the physical training protocols for prevention and treatment of obesity. As a
      consequence, future studies are required to improve obesity management and decrease
      obesity-associated complications.

      Main objective: to compare the effects of two programs of rehabilitation training associated
      with a diet supplemented with fruits and vegetables on reducing energy cost of walking in
      obese adults.

      Secondary objectives: to compare the effects of two programs of rehabilitation training
      associated with a diet supplemented with fruits and vegetables on:

        -  the mechanical properties of the lower extremity muscles,

        -  the biomechanics of walking,

        -  the walking intensity,

        -  body composition,

        -  the quality of life, and physical activities compliance and motivation,

        -  the alimentary behaviour,

        -  and the oxidative stress and the inflammatory status.

      Abstract:

      Regular physical activity associated with a hypocaloric diet and an intake of fruits and
      vegetables can reduce body fat mass and prevent the inflammatory and oxidative stress which
      are associated with obesity. Daily physical activities such as carrying bags, making
      housework, stair climbing, or simply walking, are recommended to increase total daily energy
      expenditure. However, obese individuals have a higher energy cost of walking compared with
      their lean counterparts. This higher energy cost of walking does not induce higher total
      daily energy expenditure by an increase in activity energy expenditure, but inversely,
      increases exercise intensity and reduces walking practice. It has been shown that this higher
      energy cost of walking could be due to reduced lower extremity muscle strength of obese
      individuals. Moreover, muscle strength is also reduced after a weight loss due to a decrease
      in lean body mass. However, it has been shown in lean and over-weight individuals, that
      strength training could induce a decrease of the energy cost of walking, making easier
      walking activities.

      Thus, we propose in obese patients to compare the short- and medium-term results of two
      training protocols for 5 months, both associated with a diet supplemented with fruits and
      vegetables, on reducing energy cost of walking. The study will last 9 months in total with a
      5 months training period.

      Participants will be randomized into 2 arms: arm 1 will consist of an interval strength
      training for 30 min on bicycle ergometer (which include strengthening exercises in an high
      intensity interval training), and arm 2 will consist of a isocaloric continuous exercise
      realised at moderate intensity (50 % of Vo2max) for 40 min on bicycle ergometer too.
      Participants will meet for training three times per week for 5 months under supervision of an
      exercise physiologist. All the participants will have an initial nutritional education
      session at the beginning of the study and will answer to questionnaires on training
      experience during the 5 months training period (Exercise difficulties, pain...).

      At the beginning of the study and at each follow-up visit (5th and 9th month), all
      participants will have:

        -  biological analysis : blood glucose, HbA1c, insulin, cholesterol total, HDL, LDL,
           triglycerides, C reactive protein (CRP), albumin, creatinine, urinary parameters,
           antioxidant status, inflammatory markers,

        -  maximal cardiopulmonary exercise,

        -  anthropometric and functional examinations : weight, height, waist, hip and thigh
           circumferences, blood pressure and body composition assessed by dual x-ray
           absorptiometry,

        -  laboratory tests : measurements of energy cost of walking, walking pattern on treadmill,
           and muscle strength,

        -  questionnaires on quality of life, alimentary behaviour, experience of physical
           activities and on physical activities compliance and motivation.
    

Intervention name(s): 30 minutes of high intensity training; 40 of an endurance training
Intervention type(s): Behavioral; Behavioral
Intervention description(s): This group will carry out a 5-min warm-up period on bicycle ergometer at an intensity corresponding to 50% of Vo2max before performed eight times the intermittent training exercise as follows:
30 sec at 120% of Vo2max,
1 min at 50% of Vo2max,
15 sec at 30-40 revolutions per minute of strength training at 100% of the maximal anaerobic power, which will be first determined by means of a force-velocity test on a Monark ergometer,
1 min at 50% of Vo2max.
The training session will be terminated by a 3-min cool-down period at 40% of Vo2max.
Training three times per week for 5 months under supervision of an exercise physiologist.
Initial nutritional education session at the beginning of the study Questionnaires on training experience during the 5 months training period (Exercise difficulties, pain...).
Dietary Supplement: supplementation in fruits and vegetables (5 per day) during all the study.; The moderate-intensity continuous exercise group will carry out a 40-min session of continuous cycling at a moderate intensity (50 % of Vo2max).
Training three times per week for 5 months under supervision of an exercise physiologist.
Initial nutritional education session at the beginning of the study Questionnaires on training experience during the 5 months training period (Exercise difficulties, pain...).
Dietary Supplement: supplementation in fruits and vegetables (5 per day) during all the study.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Obesity