Effectiveness of Focal Vibration and Blood Flow Restriction Within a Multicomponent Exercise Programme.

The normal ageing process is characterised by a progressive loss of muscle mass and function, this physiological process is known as sarcopenia. As a result of this loss of muscle mass and reduced efficiency of muscle enzymes, a reduction in overall strength and isometric strength in particular is observed. Secondarily, sarcopenia can occur or increase due to sedentary lifestyles, physical inactivity or chronic endocrine and inflammatory disorders. This pathology is much more frequent in older people due to the added risk factors and the fact that the physiological ageing process generates a pro-inflammatory situation and an alteration in the synthesis of hormones and myokines.

Different epidemiological studies show that maximum isometric voluntary contraction is usually maintained up to 45 years of age but its effectiveness decreases with age (25% at 65 years of age and 35% at 70 years of age). When this loss of strength or muscle mass occurs in the elderly with a baseline state of greater frailty or dependence, the clinical importance of this reduction in strength and muscle mass is much more relevant. It has been observed that the loss of strength causes functional deterioration and a significant increase in the person's dependence, reduces their functional status and quality of life, and may increase the risk of falls, thereby increasing mortality. For example, when hospital admissions occur, muscle mass decreases rapidly and in patients with femur fractures and sarcopenia it has been observed that between fracture and hospital discharge (10 days) the Barthel index decreases between 54.7% and 59.5%.

There does not seem to be a clear consensus on the diagnostic criteria for sarcopenia. Anthropometric parameters such as Skeletal Muscle Mass Index (SMMI) (≤8.87 for men and ≤6.42 for women), functional tests such as gait speed (≤0.8 metres/second) or grip strength (<30 or 20 kg for men and women respectively) are some of the most commonly used parameters in the literature for both diagnosis and monitoring of sarcopenia.

To a lesser extent, muscle cross-sectional area or contractile properties of muscle tissue could also be related to this loss of strength. More recently, and with the aim of confirming both the diagnosis and monitoring of sarcopenia, different biochemical markers have been proposed .

Regarding the treatment of sarcopenia, although there are pharmacological approaches to increase or maintain strength and muscle mass, physical activity and nutrition remain the "gold standard". Decreased physical activity level is a major aggravator of sarcopenia and sedentary lifestyles have been shown to result in accelerated loss of muscle mass, strength and functional capacity. Therefore, the American College of Sports Medicine, as well as recent research, shows that strength work at moderate to high load intensity can stimulate bone and muscle metabolism and improve overall strength, gait speed, quality of life, and reduce the risk of falls and cognitive impairment.

Despite the benefit of training at these loads, not all older people are able to perform these activities. This is due to their bone or general fragility, as well as the mechanical stress that this type of exercise produces in their joints or sedentary lifestyles. For these reasons, different types of training have emerged in rehabilitation medicine, such as blood flow restriction (BRR) and focal vibration (FV), which aim to achieve muscular hypertrophy without the need to use high loads or intensities.

BFR is training in which exercise is performed with minimal or no resistance while a pressure cuff occludes the proximal part of the limb. This situation results in partial restriction of arterial flow and more significantly venous flow in the muscles. Given the light or no load applied and the muscle hypertrophy obtained, the BFR is an effective training tool. The BFR avoids the high levels of joint stress and cardiovascular risks associated with high-load training. In the field of sports, the effects of BFR have been extensively studied and, although to a lesser extent, benefits have also been studied in the improvement of physical fitness and rehabilitation of older people.

The use of general or focused vibration is not new in the rehabilitation or de-training field. Vibration is intended to stimulate neuromuscular uses to produce involuntary and additional contractions of muscle tissue, indirectly causing an increase in strength or muscle mass, improving the prevention of falls. This type of equipment has been used both in athletes and in patients with chronic diseases or in intensive care units. There are studies that use vibration in critically ill patients as a safe and feasible intervention for dependent patients. One of the advantages of FV is that it can be used for both unloading and loading, which allows a wide range of adaptation to each patient.

Despite the observed efficacy of VF and BFR, evidence is scarce and no studies have been found to demonstrate that these devices improve the benefits of a multicomponent programme in elderly people with sarcopenia. Noeither have data been located on whether changes in biochemical markers and viscoelastic parameters are sufficiently accurate in observing increases in strength and improvements in muscle tissue.

For all these reasons, the present investigation for objectify to determine whether the use of VF or BFR brings improvements to elderly people with sarcopnoea. As well as, if the biochemical and viscoelastic markers can objectify the improvements obtained by means of the multicomponent exercise (with and without the use of BFR and VF).

The hipotesis of this study is the addition of BFR or VF techniques to training results in greater improvements in circulating myokine concentrations and functional tests than not adding it.

This study has the objective to determinate whether biochemical markers in serology are able to correlate with improvements in strength, also to study whether the plasma levels of apelin, myomyostatin and lL6 are modified with entraining, to determine whether plasma levels of apelin, myomyostatin and lL6 are further increased by training associated with VF and/or BFR and evaluate the effectiveness of different interventions in improving functional tests.

The methodology of the study is a single-blind, randomised, clinical trial will be conducted. Pilot study pre and post intervention with control group. Which will follow the CONSORT guide for the implementation of this study and the TIDier guide for the implementation of the intervention.

The study population is people over 65 years of age, sedentary, with functional independence and with a state of health that allows them to carry out physical activity. The study is planned as a pilot study and will consist of 30 subjects distributed in: 10 people in the control group (CG), 10 in the experimental vibration group (GE-V) and 10 in the experimental group with restriction (GE-R).

The variables to be measured are anthropometric variables such as height, sex, age, lower limb dominance and bioimpedance, we will also measure biochemical markers: a complete blood count will assess the levels of: Apelin (primary endpoint), myostatin, IL6, plasma proteins, uric acid and creatinine. Information about physical activity via PASE scale, variables of neuromuscular function, with Tensiomyography: Contraction time (Tc), and radial displacement (Dm), Myotonometry: Stiffness, Surface electromyography: %RMS, all of this in muscles Rectus femoris, vastus lateralis, vastus medialis, lateral gastrocnemius and tibialis anterior. Manual dynamometry: Peak force (Kg). Movements: Knee and hip flexion and extension, plantar flexion and dorsal flexion of the ankle, grip strength (Handgrip), stabilometry and ecography to measure the muscle cross-section.

Information about fragility and independence, with Barthel index, FRAIL scale, Falls Efficacy Scale I (FES-I), SARC-F. Information on functionality with Short Physical Performance Battery (SPPB), velocity in 4 meters walking, Timed get up and go (TUG).

The intervention in the control group, will be a training 3 times a week with, warm up,articular and functional exercises with one's own body weight, principal work: Aerobic training 20 minutes waking then strenght training 25 minutes, i.Sets: start with 1 set to consolidate the technique, and progress to 3 sets.

ii.Repetitions: start with 10-15 repetitions (at lower intensity) and progress to 8-12 repetitions.

iii.Intensity: start with a lower intensity (even 20-30%1RM) and progress to 70-80%1RM.

iv.Rest: Breaks between sets of 3-5 minutes should be taken to avoid muscle fatigue.

v.Exercises: Leg press on machine Balance and co-ordination training during 5-10 minutes finally return to calm during 5 minutes with stretching.

The intervention in the VF group, the frequency of training will be 3 sessions per week on alternate days, the training will consist of 20 minutes of warm up, then the prinicpal work Aerobic training: 20 minutes of treadmill walking will be performed. Strength training with VF (20-25 min) as recommended by Chow et al.

1. Aerobic training: 20 minutes of treadmill walking will be performed. We will progress from 5-10 minutes until we reach a tolerable 20 minutes. The intensity will increase progressively until reaching 12-14 on the Borg scale.
2. Strength training with VF (20-25 min) following the recommendations of Chow et al (74): i.Sets: start with 1 set to consolidate the technique, and progress to 3 sets. ii.Repetitions: start with 10-15 repetitions (at lower intensity) and progress to 8-12 repetitions. iii.Intensity: start with a lower intensity (even 20-30%1RM) and progress to 70-80%1RM. iv.Rest: Breaks between sets of 3-5 minutes should be taken to avoid muscle fatigue. v.Exercises: Leg press on machine Balance and coordination training: 5-10 minutes. Throughout the training, focal vibration will be added with the V-Plus machine (Wintecare S.A. Chiasso (Switzerland)) on the rectus anterior, vastus medialis and vastus lateralis muscles with an intensity of 120 Hz and an amplitude of 1.2 mm finally return to calm during 5 minutes with stretching.

The intervention in the BFR group the frequency of training will be 3 sessions per week on alternate days, the training will consist of 20 minutes of warm up, then the strenght training with BFR 20-25 minutes with i. Series: start with 1 series to consolidate the technique, and progress to 3 series.

ii.Repetitions: a first series of 30 repetitions and 2 series of 15 repetitions.

iii.Intensity: the exercises will be performed at an intensity of 20%1RM and may reach 30%1RM if the subject can tolerate it.

iv.Rest: Breaks of 1 minute between sets. v.Exercises: Leg press on machine vi.Cuff occlusion pressure shall be set at 50% throughout the strength training portion of the workout.

vii.The cuff shall be placed on both lower extremities, inguinal. Balance and coordination training: 5-10 minutes, finally return to calm during 5 minutes with stretching.