Using Surface Electromyography to Study Cervical Extensor Muscle Activity: An Investigation of Methodological Considerations and the Effects of Age on Fatigue Development and Recovery

Abstract

The purpose of this research was to investigate the effects of aging on fatigue onset and recovery associated with low-level exertions of the neck musculature. This investigation into aging and fatigue is unique because the bulk of fatigue research has been performed at high force levels, and/or has not considered the effects of age on fatigue development. Several methodological issues were addressed in three preliminary phases of experimentation to develop a robust electromyography (EMG) collection/processing methodology that is sensitive to low level muscular fatigue. This new methodology was then employed in the investigation of the effects of age on the fatigue response of the neck musculature during low-level exertions. The first phase was an investigation of surface electrode location, using a structured neck marking procedure, and the underlying neck musculature, using ultrasound. The second phase of this investigation, a review of signal processing theory literature and a comparison of an ideal filter with a Butterworth filter, resulted in a set of recommendations for sEMG collection methods. The third phase of this investigation, an evaluation of the effect of neck posture during a maximum volunary contraction on normalized EMG values, showed that, there were significant differences between the sEMG data normalized using the posture specific normalization method and the reference posture normalization method. The final phase of this investigation identified measures for and evaluated the effect of age on fatigue onset and recovery due to a low force, static exertion held until fatigue. Based on the results of this experiment, it was found that: • there are several quantitative measures for identifying fatigue development associated with low-level exertions; • older subjects exhibited different fatigue response patterns compared with younger subjects; • some subjects regardless of age exhibited fatigue resistant characteristics; and • the recovery rate was not significantly affected by age group.

Description

Keywords

EXTENSOR, MUSCLE, EFFECTS, AGE, FATIGUE, CERVICAL, ELECTROMYOGRAPHY, SURFACE, DEVELOPMENT, RECOVERY

Citation

Degree

PhD

Discipline

Industrial Engineering

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