The effect of the support afferentation on the parameters of the electromyographic activity and muscle tone of postural muscles in support unloading conditions
- Paper number
IAC-06-A1.3.06
- Author
Dr. Irina Sayenko, Institute for Biomedical Problems, Russia
- Coauthor
Mrs. Tatiana Miller, Institute for Biomedical Problems, Russia
- Year
2006
- Abstract
Aims Purpose was to study the effect of mechanic stimulation of the foot support zones on the tonic muscular systems under dry immersion conditions and on the patients afflicted with ischemic stroke. Method Two studies were performed. In one study, the electromyographic activity, muscle transverse stiffness of m. soleus (Sol.) and m. tibialis anterior (TA) were measured in 18 volunteers during 7-day dry immersion (DI) alone and in combination with mechanic foot stimulation. In the next study, the transverse stiffness the same muscles was measured in patients with ischemic stroke at rest and at the foot zone stimulation sessions at the beginning of recovery. The mechanical stimulation of the soles support areas, i.e. the heel and the forefoot with pressure of 0,5+0,1 kg/cm2 was applied every day for 20 minutes of every hour during 6 hours a day in regime of walking – 10 minutes of slow pacing (75 steps/min) and 10 minutes of fast one (120 steps/min). Mechanical stimulation was performed using the special device - Compensator of Support Unloading. Results The results of study show that transition to DI was followed consistently by the significant decline of electromyographic activity level of extensors. It was accompanied by the increase of flexor muscles activity. Suppression of the extensors activities developed in DI at once and was maintained unchanged through the whole time of exposure (7 days). Restoration of the activity was observed only in case of DI interruption or when mechanical stimulation of soles support zones was applied. It is important to emphasize that the response to the mechanical stimulation of the support zones of the soles carried out all features of systemic reactions. Stimulations of the fore foot zones was followed by clear contractions of ankle extensors. Stimulation of the fore feet zones on the opposite was followed by flexors contraction. During the first 24 hrs of DI the m. soleus stiffness dropped down sharply to 75Resting patients with ischemic stroke were found to have distinct asymmetric shifts in muscle tone with a prevalence of transverse flexor stiffness over extensor. Foot stimulation on the pattern of natural locomotion cancelled out the muscle tone asymmetry totally. Conclusions The results of study allow concluding that the primary response to the withdrawal of support loading is a suppression of activity of the tone muscle system. Mechanical stimulation of the support zones of the soles under supportless conditions eliminates above-mentioned effects, including changes of the transverse stiffness and the electromyographic activity of postural muscles.
- Abstract document
- Manuscript document
IAC-06-A1.3.06.pdf (🔒 authorized access only).
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