Spectral properties of myoelectric signals from different motor units in the leg extensor muscles

• DOI: 10.1242/jeb.01042
• Publication Date: 2004-06-07T19:22:56Z
• Authors: James M. Wakeling; Antra I. Rozitis
• Keywords: Motor unit; Motor Unit Recruitment; Vastus medialis

SUMMARY Myoelectric signals measured using intramuscular electromyograms (EMGs) in animals have shown that faster motor units generate higher frequencies their power spectra. However, evidence to relate myoelectric frequency and unit type from the surface typically man remained elusive. The purpose of this study was determine if spectral properties EMG could be related different muscles leg extensors man. Reflex experiments (both tendon tap electrically stimulated) graded isometric contractions were used muscle with patterns recruitment. recorded vastus lateralis medialis, rectus femoris, medial lateral gastrocnemius soleus muscles. EMGs resolved into intensities time–frequency space wavelet techniques. intensity spectra calculated for reflex responses contractile forces. compared principle component analyses ANCOVA. Electrical stimulation can result preferentially being recruited, resulted than stretch reflex. During ramped are recruited an orderly fashion slow fast. As then components appeared within For all tested there significant correlations between stage contraction frequency. Both approaches demonstrated when assumed active.