The purpose of the present study is to evaluate the acute and chronic effect of low intensity strength training with or without moderate blood flow restriction on muscle vasodilation and arterial stiffness in elders with low gait speed. In addition, the responses of prothrombotic factors in blood coagulation, the impact on heart rate and arterial pressure will be assessed.
The investigators propose a study of 26 sedentary elders with low speed gait, supervised by the Hospital Israelita Albert Einstein - Vila Mariana ambulatory. This will be an open clinical trial, prospective, single center, randomized and controlled study. It will be divided into two parts: acute and chronic phases. After signing an informed consent, the participants will be separated in two groups: Group 1. Resistance exercise with low intensity combined with partial blood flow restriction Group 2. Conventional resistance exercise with low intensity All of participants will be submitted to interventions tests before and after the period of training which are: 1. Laboratory Tests: Blood tests 2. Plethysmography 3. Handgrip 4. Quality of life questionaire 5. FMD tests 6. Vasodilation capacity
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
26
The dynamic force of the lower limb muscles will be evaluated by the maximal repetition of knee extension and leg press exercise, according to the protocol presented in a previous study \[37\]. The elderly will perform a warm up consisting of 1 series with 10 unloaded repetitions. After the warm up, the mass to be lifted will be progressively increased until the maximum load that can be lifted is reached, with a maximum limit of 5 attempts and a 3 to 5 minutes interval between them. The test will be conducted by a physical education professional who will verbally encourage participants throughout these steps and perform the load adjustment at week 5 and 10 (Radaelli, 2014).
To measure the gait speed of participants they will walk 4.6 metres and the time needed to cover this distance is measured. The mean of three attempts is recorded and divided by the distance. The participants included must achieve in the walking test an average of \< 0.,9 m/s (Guralnik, 1994).
Instituto Israelita de Ensino e Pesquisa Albert Einstein 's (IIEP)
São Paulo, São Paulo, Brazil
Anthropometric Assessment
The body weight will be evaluated using the Filizola brand scale, with an accuracy of 0.1 kg. The stature will be obtained by means of the stadiometer coupled to the Filizola scale, with an accuracy of 0.5 cm. The BMI will be calculated from the weight ratio by height squared. For measures of circumference of the quadriceps, a tape measure of the brand Seca, with precision of 0.1 cm will be used. Anthropometric measurements will be made following the standardization of the International Society for Anthropometric Assessments (ISAK, 2001).
Time frame: Before and after 12 weeksof training
Coagulation factors
Blood tests (fibrinogen, Factor VIII, von Willebrand Factor, D-dimer, t-PA and PAI 1)
Time frame: Before and after 12 weeksof training
Tolerability, adherence and adverse effects
Evaluate the tolerability, adherence and adverse effects of both groups - Questionnaire
Time frame: Before and after 12 weeks of training
Arterial pressure and heart rate
Blood pressure and heart rate measurements
Time frame: Before and after 12 weeks of training
Speed Gait
The gait velocity analysis will be performed with time marking, in thousandths of a second, from the displacement of the elderly in a 4.6-meter straight course, based on the measurement (speed / distance traveled).
Time frame: Before and after 12 weeks of training
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
A mercury-filled silastic tube, connected to a low-pressure transducer and a plethysmograph (D.E. Hokanson), will be placed around the largest circumference of the calf region. One cuff will be placed around the ankle and another around the thigh. The ankle cuff will be inflated to a supra-systolic pressure 30 seconds before starting the measurements. At 15-second intervals, the cuff around the thigh will be inflated above the venous pressure for a period of seven to eight seconds. Increased tension in the silastic tube reflects an increase in leg volume and vasodilation. The signal of the muscle blood flow wave will be recorded on a polygraph and analysed every minute, averaging three records per minute. The protocol will be performed during 5 minutes of rest, 3 minutes isometric exercise and 2 minutes of recovery (Bahia, 2006).
Arterial stiffness will be estimated from the carotid-femoral aortic pulse wave velocity \[33\]. Carotid-femoral aortic pulse waves will be recorded by tonometry (SphygmoCor, AtCor Medical, Australia). At the same time, an electrocardiogram will be obtained to calculate the wave transit time. Two distances will be measured: the recording point of the carotid artery and the sternal furcula (distance 1) and the sternal furcula and the recording point in the femoral artery (distance 2). The distance travelled by the pulse wave will be calculated as "distance 2" - "distance 1". The carotid-femoral aortic pulse wave velocity will be calculated as: carotid-femoral aortic pulse wave velocity = ¼ \* distance travelled by the pulse wave (m) / transit time(s).
In a supine position, the maximal voluntary handgrip force will be determined as the highest force in 3 consecutive attempts using a Jamar hydraulic palmar dynamometer (Asimow Engineering, CAL, USA). For activation of the central command, mechanoreceptors and muscular metaboreceptors the individual will perform, after 5 minutes of rest (baseline records), 3 minutes of exercise at 30% MVC. This manoeuvre isolates the activation of muscle metaboreceptors, observing the selective activation of these. After the isometric handgrip exercise, 2 minutes of recovery will be performed. Throughout the protocol muscle blood flow, blood pressure and heart rate will be recorded.
The vasodilatory capacity will be calculated as the percentage of increase of the diameter of the brachial artery and femoral post occlusion in relation to its basal values.
Images of the brachial artery will be recorded by a two-dimensional ultrasonography device with a spectral Doppler and linear transducer (Ultra-0122, Philips, The Netherlands).
This questionnaire is used to estimate the quality of life in participants before and after the study.
Anthropometric measurements will be made before and after the training program following the standardization of the International Society for Anthropometric Assessments. The body mass will be measured with an accuracy of 0.1 kg (Filizola). The stature will be obtained by means of the stadiometer with an accuracy of 0.5 cm. The BMI will be calculated as body mass divided by height squared. The circumference of the quadriceps will be measured with a tape measure (Seca) with a precision of 0.1 cm.