Muscle Movement and Electrodes Motion Artifact during Vibration Treatment
Vibration treatment by oscillating platforms is more and more employed in the fields of exercise physiology and bone research. The rationale of this treatment is based on the neuromuscular system response elicited by vibration loads. surface Electromyography (EMG) is largely utilized to assess muscular response elicited by vibrations and Root Mean Square of the electromyography signals is often used as a concise quantitative index of muscle activity; in general, EMG envelope or RMS is expected to increase during vibration. However, it is well known that during surface bio-potential recording, motion artifacts may arise from relative motion between electrodes and skin and between skin layers. Also the only skin stretch, modifying the internal charge distribution, results in a variation of electrode potential. The aim of this study is to highlight the movements of muscles, and the succeeding relevance of motion artifacts on electrodes, in subjects undergoing vibration treatments.
EMGs from quadriceps of fifteen subjects were recorded during vibration at different frequencies (15–40 Hz); Triaxial accelerometers were placed onto quadriceps, as close as possible to muscle belly, to monitor motion. The computed muscle belly displacements showed a peculiar behavior reflecting the mechanical properties of the structures involved. Motion artifact related to the impressed vibration have been recognized and related to movement of the soft tissues. In fact large artifacts are visible on EMGs and patellar electrodes recordings during vibration. Signals spectra also revealed sharp peaks corresponding to vibration frequency and its harmonics, in accordance with accelerometers data.
Keywordsvibration treatment muscle movement electromyography motion artifact
Unable to display preview. Download preview PDF.
- 3.Bongiovanni LG, Hagbarth KE. TVR elicited during fatigue from maximal voluntary contractions in man. Journal of Physiology 1990;4231:14Google Scholar
- 5.Hermens HJ, Freriks B, Merletti R, Stegeman D, Blok J, Rau G, Disselhorst-Klug C, Hägg G. European Recommendations for Surface ElectroMyoGraphy, Results of SENIAM Project. 8th ed. Enschede: Roessingh Research and Development, 1999Google Scholar
- 13.Wakeling JM, Nigg BM. Modification of soft tissue vibrations in the leg by muscular activity. Journal of Applied Physiology 2001;90(2):412–20Google Scholar
- 14.Wakeling JM, Nigg BM, Rozitis AI. Muscle activity damps the soft tissue resonance that occurs in response to pulsed and continuous vibrations. Journal of Applied Physiology 2002;93(3):1093–103Google Scholar