Tonic vibration reflex is a sustained contraction of a muscle subjected to vibration. This reflex is caused by vibratory activation of muscle spindles — muscle receptors sensitive to stretch.
Tonic vibration reflex is evoked by placing a vibrator — which in this case is typically an electrical motor with an eccentric load on its shaft — on a muscle's tendon. 30–100 Hz vibration activates receptors of the skin, tendons and, most importantly, muscle spindles. Muscle spindle discharges are sent to the spinal cord through afferent nerve fibers, where they activate polysynaptic reflex arcs, causing the muscle to contract.
The effects of sustained vibratory stimulation on muscle contraction, posture and kinesthetic perceptions are much more complex than merely contraction of the muscle being vibrated.
Russian scientists Victor Gurfinkel, Mikhail Lebedev, Andrew Polyakov and Yuri Levick used vibratory stimulation to study human posture control and spectral characteristics of electromyographic (EMG) activity.
Gurfinkel, V.S., Lebedev, M.A., Levick, Yu. S. (1992). "What about the so-called neck reflexes in humans?". In Bertoz, A., Graf, W., Vidal, P.P. (ed.). The Head-Neck Sensory Motor System. Oxford University Press. pp. 543–7. doi:10.1093/acprof:oso/9780195068207.003.0086. ISBN9780195068207.{{cite book}}: CS1 maint: multiple names: authors list (link)
Gurfinkel' VS; Lebedev MA; Levik IuS (1992). "[Switching effect in the system of equilibrium regulation in man]". Neirofiziologiia (in Russian). 24 (4): 462–70. PMID1436211. English Translation
Gurfinkel', V. S.; Lebedev, M. A.; Levik, Yu. S. (1993). "Effects of reversal in the human equilibrium regulation system". Neurophysiology. 24 (4): 297–304. doi:10.1007/BF01057332. S2CID46510709.
Lebedev MA, Polyakov AV (1992). "Analysis of surface EMG of human soleus muscle subjected to vibration". J Electromyogr Kinesiol. 2 (1): 26–35. doi:10.1016/1050-6411(92)90005-4. PMID20870524.
Gurfinkel, V.S., Levick, Yu. S. Lebedev, M.A. (1991). "Body scheme concept and motor control. Body scheme in the postural automatisms regulation". Intellectual Processes and Their Modelling. Moscow: Nauka. pp. 24–53.{{cite book}}: CS1 maint: multiple names: authors list (link)
Lebedev MA, Poliakov AV (1991). "[Analysis of the interference electromyogram of human soleus muscle after exposure to vibration]". Neirofiziologiia (in Russian). 23 (1): 57–65. PMID2034299. English Translation
Lebedev, M. A.; Polyakov, A. V. (1991). "Analysis of the interference electromyogram of the human soleus muscle under vibrational stimulation". Neurophysiology. 23: 47–54. doi:10.1007/BF01052289. S2CID19403562.