Whole Body Vibrations on Functional Capacity, Muscular Strength, and Biochemical Profile in Elders

After evaluating the anamnesis and having the written consent signed and clarified, the elderly women will be evaluated before and after the intervention period of 8 weeks of training on the vibratory platform. First, academics from the nutrition degree of the University of Santa Cruz do Sul (UNISC) will perform nutritional evaluations on the subjects, asking them their 24 hour eating habits, there will not be any interference on the subjects diet, also they will have to keep these habits until the end of the trial. Then there will be a socio-economical indicators evaluation through a questionnaire of socio-economical classification from the Brazilian Association of Research Companies.The evaluation of their level of physical activity will be done by the International Physical Activity Questionnaire. The anthropometrical evaluation will consider height, weight, body mass index, waist circumference, hip circumference, and hip-waist ratio. Body fat percentage, lean mass, and basal metabolic rate will be obtained through bioimpedance (Biodynamics 450, USA), recommending 5 hours fasting prior to the procedure. Biochemical tests will be done collecting blood at the University of Santa Cruz Exercise Biochemistry Laboratory, on the following variables: hemogram, glycemia, cholesterol, triglycerides, Urea, creatine, uric acid. Oxidative stress evaluation with the Thiobarbituric acid reactive substances (TBARS) test will be done after urine collection once a week, before intervention and immediately after the session. Control group subjects will have urine collected twice: on the day when cards will be handed in and on the last day of evaluations. Physical evaluation will be done in the week prior to the intervention with the vibratory platform and in the last week of treatment, where flexibility through Wells Bank will be evaluated, as well as lower limb muscular strength by the maximum repetitions test, and palmar prehension strength will be obtained through dynamometer. Functional Capacity will be evaluated with the six minute walk test.

The intervention procedure with the vibratory platform (Power Plate®, model my7™, UK) will last 8 weeks, 3 times a week with work periods lasting between 30 seconds and 1 hour and rest periods of 30 seconds to 1 minute with a total session time of 10 to 20 minutes. The individual will be then positioned in orthosis with a knee flexion of a 15° and a foot width distance of 20 cm. A frequency of 35 Hz and an amplitude of 2 mm will be used. The protocol with number of session, time of session, time of vibrations and rest, is as follows: 1st through 6th session, total time of 10 minutes, with 30 seconds of vibration alternated with 1 minute rest; 7th through 12th session, total time of 10 minutes, vibrations and rest time of 1 minute each; 13th trough 18th session, total session time of 15 minutes, vibrations and rest time of 1 minute each, 19th through 24th session, total time of 20 minutes, time of vibration 1 minute and rest time of 30 seconds.

Statistical analysis: This will be done using the Statistical Package for Social Science (Version 23.0 USA) program. To test data normality the investigators will use the Kolmogorov-Smirnov test. Parametric data will be presented in mean and standard deviation and non-parametric data in median and interquartile intervals. The intragroup deltas from the pre and post training periods on the vibratory platform on both groups will be evaluated through Student´s T Test (paired T test or non-parametric equivalent for intergroup comparisons).

To evaluate body composition, metabolic rate, palmar prehension strength, flexibility, muscular strength, distance traveled through the Six minute walking test (6SMWT), biochemical profile and oxidative stress between the groups evaluated pre and post training period, a Student´s T test will be used. Significance level will be p < 0,05.

Sample size: It was based on a previous study by Rees et al. (2008). To detect a difference of 8,9 W/Kg between knee flexion torque pre and post training on the vibratory platform, considering a p value < 0,05, a statistical power of 80% and a 10% loss, 34 subjects will be needed in each group to be evaluated in pre and post training.