Wavelet-Based Mechanomyographic Intensity Responses to Sustained Tasks Anchored to Low Versus High Ratings of Perceived Exertion

Authors

Dolores G. Ortega, University of Nebraska - LincolnFollow
Robert W. Smith, Lindenwood UniversityFollow
Jocelyn E. Arnett, University of Nebraska - LincolnFollow
Tyler J. Neltner, University of Wisconsin - PlattevilleFollow
Trevor D. Roberts, University of Nebraska - LincolnFollow
Justin S. Pioske, University of Nebraska - LincolnFollow
Richard J. Schmidt, University of Nebraska - LincolnFollow
Terry J. Housh, University of Nebraska - LincolnFollow

Abstract

Purpose: This study examined the effects of sustained, isometric forearm flexion tasks anchored to ratings of perceived exertion of 2 (RPE2_FT) versus 8 (RPE8_FT) on the wavelet-based mechanomyographic (MMG) intensity responses from pretest and posttest maximal voluntary isometric contractions (MVICs) as well as the time course of changes in the MMG intensity responses throughout the sustained tasks. Methods: Eleven men (mean±SD: age=20.9±2.3 yrs) performed MVICs before and after the sustained tasks. The wavelet analyses decomposed the MMG signals onto a set of 11 wavelet bands (WBs). Repeated measures ANOVAs were used to analyze the MMG intensity data. Results: For the MVICs, there were WB-specific differences in MMG intensity (lowest:0.02%[WB1] and highest:49.77%[WB3]), but no RPE- or time-specific differences. For both sustained tasks, MMG intensity decreased at WBs 3-11, which resulted in a decrease in total intensity (100.00% vs. 17.10%), but no changes at WBs 1 and 2. Conclusion: The lack of change in MMG intensity from pretest to posttest MVIC was likely due to the restriction of the lateral oscillations of the activated muscle fibers that resulted from muscle stiffness, intramuscular fluid pressure, and/or a fusion-like state of the motor units due to their high firing rate. The decreases in MMG intensity throughout the sustained tasks at the medium and higher WBs were likely due to the de-recruitment of medium and higher thresholds motor units, but not of lower threshold motor units. Thus, the responses during maximal measurements versus the time course of changes provided different information, however, the responses were not RPE-dependent.

Recommended Citation

Ortega, Dolores G.; Smith, Robert W.; Arnett, Jocelyn E.; Neltner, Tyler J.; Roberts, Trevor D.; Pioske, Justin S.; Schmidt, Richard J.; and Housh, Terry J. (2026) "Wavelet-Based Mechanomyographic Intensity Responses to Sustained Tasks Anchored to Low Versus High Ratings of Perceived Exertion," Journal for Sports Neuroscience: Vol. 1: Iss. 2, Article 26.
Available at: https://nsuworks.nova.edu/neurosports/vol1/iss2/26