Is the Focal Muscle Vibration an Effective Motor Conditioning Intervention? A Systematic Review

Abstract

Mechanical vibration, applied to single or few muscles, can be a selective stimulus for muscle spindles, able to modify neuromuscular management, inducing short and long-term effects, are now mainly employed in clinic studies. Several studies reported as treatments with focal vibratory (FVT) can influence neuromuscular parameters also in healthy people. However, the application modalities and the consequent effects are remarkably fragmented. This paper aims to review these studies and to characterize the FVT effectiveness on long-term conditional capacities in relation to FVT characteristics. A systematic search of studies published from 1985 to 2020 in English on healthcare databases was performed. Articles had to meet the following criteria: (1) treatment based on a locally applied vibration on muscle belly or tendon; (2) healthy adults involved; (3) outcomes time analysis enduring for more than 24 h. Twelve studies were found, all of them presented an excellent quality score of ≥75%. All selected papers reported positive changes, comparable with traditional long-lasting training effects. Muscle force and power were the most investigated parameters. The after-effects persisted for up to several months. Among the different FV administration modalities, the most effective seems to show a stimulus frequency of ≈100 Hz, repeated more times within three-five days on a voluntary contracted muscle.

Plastic changes induced by muscle focal vibration: A possible mechanism for long-term motor improvements

“…In the reported studies showing complex and sudden after-effects, the vibration was applied while the subject maintained the vibrated muscle in a state of mild voluntary isometric contraction. In the absence of this condition, the results were contradictory, showing either short (Fattorini et al, 2021) or no effects (Brunetti et al, 2006(Brunetti et al, , 2012(Brunetti et al, , 2015Fattorini et al, 2006;Marconi et al, 2008;Filippi et al, 2009;Pettorossi et al, 2015).…”

“…Several studies have examined the effects of focal vibration on healthy individuals. In a recent review (Fattorini et al, 2021) the focus was on the long-lasting after-effects of RFV, ranging from 24 h to several months after the end of RFV, in healthy individuals. In most of the articles listed in the review, only one muscle was stimulated.…”

“…To ameliorate motor performance, several authors stimulated proprioceptive sensors by applying a prolonged and repeated mechanical vibration on a muscle or tendon (RFV, repeated focal vibration). RFV has been found to induce, in most cases, long-term (days, weeks, or months) improvements of motor performances in both healthy and diseased individuals (Murillo et al, 2014;Souron et al, 2017a;Alghadir et al, 2018;Fattorini et al, 2021). Even though the results were mainly related to the function of the single treated muscle, RFV has been found to induce complex, unexpected, and still unexplained motor effects also involving untreated muscles.…”

Myths and truths on biophysics-based approach in rehabilitation of musculoskeletal disorders

“…41 Vibrational therapy is a technique used in rehabilitation that aims at improving proprioception and muscle strength, with results depending on the frequency of stimulation, varying from 50 to 300 Hz. [42][43][44] There could be whole body vibration therapy, in which exercise is performed on a vibrating platform, or focal vibration therapy, focused on a muscle or a group of muscles. 42,43 A systematic review published in 2009 underlined that knowledge on whole body vibration is still weak and more high-quality studies are needed to comprehensively evaluate this therapy.…”

Effects of prolonged local vibration superimposed to muscle contraction on motoneuronal and cortical excitability

“…While most of the studies on effects of LV have been obtained while applying LV to relaxed muscles ( Noma et al, 2012 ; Tavernese et al, 2013 ), there exist alternative studies within the literature that applied LV on contracted muscles ( Marconi et al, 2011 ; Celletti et al, 2017 ), considering that contraction may increase Ia afferents discharge (and likely optimize LV effects) through increased α-γ co-activation ( Burke et al, 1976b ). In a recent systematic review including 12 studies investigating the potential for LV to induce some motor conditioning, it was accordingly suggested superimposing LV to muscle contraction may be more effective ( Fattorini et al, 2021 ). Yet, there is a paucity of studies comparing LV applied on relaxed vs. contracted muscles ( Filippi et al, 2009 ; Brunetti et al, 2012 ) so that cumulative evidence is needed.…”