Effectiveness of Focal Vibration and Blood Flow Restriction Within a Multicomponent Exercise Programme for Non-dependent and Sedentary Elderly People. Effects on Biochemical Markers and Functional Tests. Pilot Study.

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.