title: Wavelet-based intensity analysis of the mechanomyograph and electromyograph during the H-reflex.
abstract: OBJECTIVE
  The relationship between mechanomyography (MMG) and electromyography (sEMG) during electrically evoked muscle contraction was examined using the von Tscharner "intensity analysis," which describes the power of a non-stationary signal as a function of both frequency and time.
  
  
  METHODS
  Data for 8 college-aged participants (3 males; 5 females) with measurable H-reflexes were analyzed. Recruitment curves for H-reflex (H), M-wave (M) using sEMG, and peak-to-peak MMG (MMGp-p) were elicited through incremental tibial nerve stimulation. The maximum peak-to-peak values for H and M for each sample were summed (HM); and maximum intensity values were measured for MMG, H, and M following the intensity analysis and computation of total intensity (MMGCvT, HCvT, MCvT). HCvT and MCvT were subsequently added together (HMCvT) for comparisons.
  
  
  RESULTS
  Correlations of HM:MMGp-p, HM:MMGCvT, HMCvT:MMGCvT, HMCvT:MMGp-p, were low (r = 0.34, 0.33, 0.09, and 0.12, respectively, p < 0.001); and correlations of HM:HMCvT, MMGCvT:MMGp-p, were moderate-to-high (r = 0.69 and 0.97, respectively, p < 0.001). Correlations for individuals ranged from 0.61 to 0.99 across comparisons. The time at which maximal intensities occurred reflected the transition from a predominant H-reflex to the onset of the M-wave and declining lag times were noted with increasing intensity.
  
  
  CONCLUSIONS
  The intensity analysis provides insight into the frequency characteristics of the H-reflex and M-wave not seen in traditional analysis of the H-reflex. The intensity analysis may be a useful tool in studying individual variations and changes in the contraction velocities of skeletal muscle.
authors.affiliation: Division of Health and Physical Education, Western Oregon University, 345 N. Monmouth Avenue, Monmouth, OR, 97361, USA, armstroj@wou.edu.
authors.forename: W Jeffrey
authors.initials: WJ
authors.lastname: Armstrong
mesh_terms: D000293:Adolescent; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D058067:Wavelet Analysis; D055815:Young Adult