Effects of Anchor Scheme on Torque and Neuromuscular Responses During and Following Fatiguing Isokinetic Forearm Flexion Tasks: Insights from High-Density Electromyography and Wavelet Analysis

Authors

• Dolores Guadalupe Ortega, University of Nebraska-LincolnFollow

First Advisor

Terry Housh

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Dona McCanlies, Heather Rasmussen, Richard Schmidt

Department

Nutrition

Date of this Version

6-23-2026

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree Doctor of Philosophy

Major: Nutrition

Under the supervision of Professor Tery Housh

Lincoln, Nebraska, May 2026

Comments

Copyright 2026, Dolores Guadalupe Ortega. Used by permission

Abstract

This study examined the effects of anchor scheme on torque and neuromuscular responses during and following fatiguing isokinetic forearm flexion tasks. Thirteen men (mean ± SD; age: 22.0 ± 1.9 yr; height: 183.0 ± 6.4 cm; body mass: 90.2 ± 18.1 kg) completed pretest and posttest maximal, concentric, isokinetic forearm flexion muscle actions at 30°∙s-1 before and after continual, concentric, isokinetic forearm flexion tasks at 30°∙s-1 at an RPE of 6 (RPE6T) and the torque (TRQ6T) produced during the first repetition of the RPE6T. Monopolar electromyographic (EMG) signals were recorded from the biceps brachii using a high-density EMG sensor. A miniature accelerometer was used to record the mechanomyographic (MMG) signals. The signals were processed using wavelet analyses, which decomposed the signals onto sets of 11 nonlinearly scaled Cauchy wavelets that span the frequency range of each signal. A Fatigue Task Questionnaire (FTQ) was used to assess the contribution of perceived sensations and psychological factors to task termination. Mean differences for repetitions to failure (RTF) and the FTQ item scores were assessed using paired samples t-tests. Repeated measures ANOVAs were used to examine the mean differences for torque and the dependent variables obtained from the wavelet analyses. The RPE6T resulted in greater RTF than the TRQ6T, despite similar pretest to posttest decreases in torque. The anchor scheme of the fatiguing tasks influenced the pretest to posttest changes in MMG wavelet band intensity, as well as the time courses of change in torque and EMG wavelet band intensity, but not the pretest to posttest changes in EMG wavelet band intensity. There were no pretest to posttest changes in EMG or MMG total intensities. There were also no changes in MMG wavelet band intensity during the RPE6T and TRQ6T. Loss of focus, a mismatch in effort, and boredom had a greater contribution to task termination during the RPE6T than the TRQ6T. Collectively, these findings indicated that the anchor scheme affected the torque and neuromuscular responses during the fatiguing tasks. Furthermore, EMG and MMG wavelet analyses may be sensitive to the fatigue-induced changes in motor unit activation strategies that modulate torque production.

Recommended Citation

Ortega, Dolores Guadalupe, "Effects of Anchor Scheme on Torque and Neuromuscular Responses During and Following Fatiguing Isokinetic Forearm Flexion Tasks: Insights from High-Density Electromyography and Wavelet Analysis" (2026). Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–. 511.
https://digitalcommons.unl.edu/dissunl/511