The effect of vibration on EMGrms activity of skeletal muscle

The assessment of the neuromuscular behaviour has received in the last decades a strong improvement through the evolution of diagnostic technique. This was allowed by the creation of new dedicated instruments and apparatus that have been used mainly in the field of rehabilitation and sport medicine. However, the assessment of the neuromuscular functions is steel far to be enough complete for covering the large spectrum of biological changes which occurs with injures and after surgery. In fact, there is an high percentage of patients showing a weakness of the leg extensor muscles after a long follow-up period - most likely due to the severing of propioceptors during surgery (1).

Even if such problems are well known there is an inadequate and lack of specific evaluation technique that could allow the quantification and assessment of the impairment due to the proprioceptors inability to function properly. In this respect, it was conduced a pilot investigation to analyse the possibility for detecting and quantifying the operated knee joint propioceptors functional capacity. For this purpose a new diagnostic technique, consisting on monitoring the muscles EMGrms activity during vibration, was applied for identify altered neural strategies of motoneuron pool recruitment. Previous findings of EMGrms recorded in biceps brachii of boxers (2), showed a significant enhancement (P<0.001)>.

It has been demonstrated that vibration drives alpha - motoneurons via Ia loop producing force without descending motor drive (5). In addition, it has been shown that vibration-induced activation of muscle spindle receptors, not only in the muscle to which vibration was applied, but also to the neighbouring muscles (6). Mechanical vibration (10-200 Hz) applied to muscle belly or tendon can elicit reflex contraction (7). This response has been named “ tonic vibration reflex “ (TVR).

It has been also argued that in the presence of TVR, the vibration-induced suppression of motor output in maximal voluntary contractions probably does not depend to the voluntary command Methods of functional testing during rehabilitation exercises 22 (8). It was suggested that contributing mechanism might be vibration induced pre-synaptic inhibition and/or transmitter depletion in the group Ia exitatory pathways which constitute the afferent link of the gamma-loop (8). In light of the above findings, a pilot study was planned to introduce a new assessment strategy to identify muscle behaviour and possibly dysfunction.

Refferences:
1. Engel A, Petschnig R, Baron R, et al. (1990) The effect of meniscectomy on the strength of the femoral quadriceps muscle after more than 3 years.wien Klin Wochenschr 102, 22:663–6
2. Augustsson J, Esko A, Thomee R, et al. (1998) Weight training of the thigh muscles using closed ve open kinetic chain exercises : a comparison of performance enhancement. J Orthop Sports Phys Ther 27, 1: 3-8
3. Burke JR, Schutten MC, Koceja DM, et al. (1996). Age-dependent effects of muscle vibration and the Jendrassik maneuver on the patellar tendon reflex response. Arch Phys Med Rehabil 77 ,6:600-604
4. Lebedev MA, Peliakov AV (1991). Analysis of the interference electromyogram of human soleus muscle after exposure to vibration. Neirofiziologia 23, 1: 57-65 (article in Russian).
5. Rothmuller C, Cafarelli E (1995). Effects of vibration on antagonist muscle coactivation during progressive fatigue humans. J Physiol 485: 857-864
6. Kasai T, Kawanishi, Yahagi S (1992) The effects of wrist muscle vibration on human voluntary elbow flexionextension movements. Exp Brain Res 90: 217–220
7. Hagbarth KE, Eklund G(1965) Motor effects of vibratori stimuli. In: Granit R (Ed.) Muscular afferents and motor control. Proceedings of the First Symposium, Almqvist and Wiksell, Stockholm pp 177–86
8. Bongiovanni LG, Hagbarth KE, Stjenberg L (1990) Prolonged muscle vibration reducing motor output in maximal voluntary contractions in man. J Physiol (Lond) 423:15-23.

List of Publications

LIST OF PUBLICATIONS

- Bosco C., Cardinale M., Tsarpela O., Colli, R., Tihanyi J., von Duvillard S.P., Viru A. (1998). The
influence of whole body vibration on jumping performance. Biology of Sport (15), 3: 157-164
- Bosco C., Cardinale M. (1998). Nuove frontiere dell’allenamento sportivo : le vibrazioni.
Effetti sul comportamento meccanico del muscolo scheletrico. Coaching & Sport Science Journal, 3 (1): 53-59
- Bosco, C., Colli, R., Introini, E., Cardinale, M., Tihanyi, J., von Duvillard S., &Viru, A. (1999). Adaptive responses of human skeletal muscle to vibration exposure. Clinical Physiology, (19), 2: 183-187
- Bosco C., Cardinale, M., Tsarpela O. (1999). Influence of vibration on mechanical power and electromyogram activity in human arm flexors muscles. European Journal of Applied Physiology, 79: 306-311
- Bosco, C., Iacovelli, M., Tsarpela, O., Cardinale, M., Bonifazi, M., Tihanyi, J., Viru, A. (1999).
Effect of acute whole body vibration treatment on mechanical power, electromyogram and hormonal profile of male athletes. In: Proceedings of the 4th Annual Congress of the European College of Sport Science. Pp.279
- Bosco C., Colli, R., Cardinale M., Tsarpela O., Bonifazi, M., (1999). The effect of whole body vibration on mechanical behavior of skeletal muscle and hormonal profile. Musculo Skeletal Interactions; basic and clinical aspects. Volume 2: pp.67-76. Eds. GR Lyritis Hylonome Editions ISBN 960-86410-0-4
- Bosco, C., Cardinale, M., Tsarpela, O., & Locatelli, E. (1999). New trends in coaching science: The use of vibrations for enhancing performance. New Studies in Athletics, 14 (4): 55-62
- Bosco, C., Iacovelli, M., Tsarpela, O., Cardinale, M., Manno, R., Tihanyi, J., Viru, M., De Lorenzo, A. & Viru, A. (2000). Hormonal responses to whole body vibrations in man. European Journal of Applied Physiology, 81 (6): 449-454
- Cardinale, M., (2000). Le vibrazioni: aspetti fisiologici ed effetti sul profilo ormonale. Scienza della Riabilitazione, 1 (1-2): 15-19 (ISSN 1590-6647)
- Cardinale, M., Andersson, H.(2000). Forbattring av prestationsformagan genom vibrationstraining. Idrottforskning , 3 (9): 45-49
- Cardinale, M., Bosco, C. (in-press). The use of vibration as an exercise intervention. Exercise and Sport Sciences Reviews.

Vibration Training Effect on Bones and Neurotransmitters

Bones:

Bone decalcification (osteoporosis) is one of the biggest health problems especially in the elderly and women population. Many elderly people break their bones more easily when they fall because of bone decalcification; the hip is the most notorious in this respect. The onset of osteoporosis is partly due to a lack of movement, which causes muscles to gradually weaken, the circulation to diminish and the bones to be inadequately used. In addition, as a result of the ageing process, the body produces fewer hormones such as testosterone, estrogen and growth hormone. Yet it is exactly these hormones, which play such an important role in the maintenance of strong bones.

The advice usually given to sufferers of this disease is to take more exercise, but that is difficult when muscles are weak, particularly in the legs. The NEMES BOSCO-SYSTEM offers a good alternative to vigorous impact exercise: through vibration the muscles automatically become stronger and regain their tone. The circulation improves because the blood vessels in the legs are wide open due to the vibration. At the same time, the pulsation gives a direct stimulus to bone tissue, which in turn stimulates the production of new bone tissue.

Scientific research shows that vibration training can help against osteoporosis. Recent findings show that even after only one vibration treatment, there is an increase in the hormone testosterone and growth hormone, which are so essential for strong bones.

Neurotransmitters:
Parkinson's Disease is an example of a deficiency in dopamine, which is the reason that L-Dopa is given as medicine. It is also recognized that serotonin plays a role in our mood, or frame of mind. A shortage of serotonin in the brain can lead to depression, which is the reason that Prozac is given as a medicine in order to increase the serotonin content in the brain. From research, it appears that vibration training also influences the neurotransmitters and the way in which they work. Vibration training increases the serotonin content in the brain, which could possibly explain why one feels so well after vibration training.

Scientific Basis of Vibrations

The facilitation of the excitability of the spinal reflex has been elicited through vibration of the quadriceps muscle (Burke et al. 1996). Lebedev and Peliakov (1991) have also suggested the possibility that vibrations may elicit excitatory inflow through muscle spin dle-motoneurons connections in the overall motoneuron inflow.

It has been demonstrated that vibration drives alpha-motoneurons via the la loop producing force without decreasing motor drive (Rothmuller and Cafarelli, 1995). Although it has been suggested that the vibration reflex, like the tendon jerk reflex, operates predominantly or exclusively on alpha motoneurons and does not utilise the same cortical originating efferent pathways as are used when performing voluntary contractions (Burke et al. 1976). It cannot be excluded that vibration treatments can also affect voluntary movements. These suggestions are supported by the present findings. In fact the EMG recorded in the biceps brachii of the experimental group in the study conducted on boxers showed a significant enhancement (P<0.001).>

One of the first and major scientists who became interested in the effects of vibrations on human performance was Prof. Carmelo Bosco. The interest that Bosco had since 1992 (Belli and Bosco, Acta Physiol Scand 144, 1992) for the muscular response to mechanical stimulation, coupled with the more recent studies on hormones, paved the way to his last research topic: vibration, a force which we are unconsciously constantly exposed to. "Running, hunting, fighting, playing the drums and dancing, navigating the oceans, cutting trees and giving life to the first villages or travelling in a high speed train, men since always have been exposed to thousand types of vibration".

The concept of Neuro-Muscular Mechanical Stimulation (NEMES) is based on this brilliant intuition on how to use existing natural forces to improve our condition. Today this is the name of one of our innovative product lines based on the use of mechanical vibrations. Quickly a number of researches demonstrated the extraordinary effectiveness of this method bringing though also to light the importance of dosing the stimulation and the protocols on the base of highly individually characterized responses (Bosco et al., Biology of Sport, 15, 1998) (Bosco et al., Eur J Appl Physiol 79, 1999(Bosco et al., Clincal Physiol, 19, 1999) (Bosco et al., Eur J Appl Physiol, 81, 2000)And it is through these last researches that the patent that differentiates the NEMES products originates. The NEMES products are the only machines in the world equipped with an advanced system able to detect the muscular response to vibration through electromyography (EMG) and to identify the optimal vibration frequency for each subject.

From the studies on vibration emerges also the great stimulation that this method induces on bone tissue making it an optimal candidate for the prevention and cure of pathologies like osteoporosis. These studies open the road to a definition of new methodologies of training based on deep physiological knowledge.