Motor performance changes induced by muscle vibration
Luigi Fattorini (1), Aldo Ferraresi (2), Angelo Rodio (3), Gian Battista Azzena (2), Guido Maria Filippi (2)
(1) Dept. of Human Physiology, University of Rome, (2) Institute of Human Physiology, Università Cattolica di Roma, (3) Department of Motor Sciences and Health, University of Cassino
Eur J Appl Physiol (2006) 98:79–87
Method: The possibility that mechanical stimulation of selected muscles can act directly on the nervous system inducing persistent changes of motor performances was explored. On the basis of literature, stimulating parameters were chosen to stimulate the central nervous system and to avoid muscle fibre injuries. A sinusoidal mechanical vibration was applied, for three consecutive days, on the quadriceps muscle in seven subjects that performed a muscular contraction (VC).
The same stimulation paradigm was applied on seven subjects in relaxed muscle condition (VR) and seven subjects were not treated at all (NV). Two sessions (PRE and POST) of isometric and isotonic tests were performed separated for 21 days, in all studied groups 7 days before and 15 days after stimulation, whilst an isokinetic test was performed on VC only. In the isometric test, the time of force development showed a significant decrease only in VC (POST vs PRE mean 27.8%, P < 0.05).
In the isotonic test, the subjects had to perform a fatiguing leg extension against a load. In this condition, the fatigue resistance increased greatly in VC (mean 40.3%, P < 0.001), increased slightly in VR and there was no diVerence in NV. In Isokinetic test, at several angular velocities, significantly less time was required to reach the force peak (mean 20.2% P < 0.05).
The findings could be ascribed to plastic changes in proprioceptive processing, leading to an improvement in knee joint control. Such action delineates a new tool in sports training and in motor rehabilitation.
Conclusions: In this research it was evidenced that through particular conditioning applied protocol it is possible to induce a persisting motor performance improvement, otherwise only obtainable after many weeks of specific physical training programs not only in healthy subjects but also in
rehabilitation programs (Brunetti et al. 2006). Moreover, presented data show that the protocol can enhance FD and fatigue resistance.