Date of Award

2004

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Computing, Health and Science

First Advisor

Dr Angus Burnett

Abstract

Neck pain in occupational tasks is a problem that involves a high cost to society therefore, understanding the mechanics of musculoskeletal loading is important in formulating preventative rehabilitation strategies. Musculoskeletal modelling of the neck provides a means by which to calculate loads on the components and muscles of the neck thus allowing quantitative data to be gained non-invasivcly for a wide range of occupational tasks. Anatomically detailed, electromyography (EMG) driven neck models require deep muscle EMG activation profiles which arc difficult to attain without invasive EMG procedures. The aim of this study was to determine whether EMG activity of semispinalis capitis (a posterior deep neck muscle) could be predicted from the EMG activity of trapezius (a posterior superficial neck muscle) and whether EMG activity from splenius capitis (a posterolateral deep neck muscle) could be predicted from the EMG activity of levator scapulae (a representative posterolateral superficial muscle). Surface EMG was recorded unilaterally from two sites around the neck at the C4/5 level and intramuscular EMG was recorded using fine-wire EMG electrodes on six healthy male subjects. Subjects performed a series of maximal and sub-maximal isometric contractions against the torque arm of an isokinetic dynamometer in the direction of extension and right lateral bending with the head in neutral and non-neutral (20° flexion, 35° extension and 30° lateral bending) postures. EMG data were normalised using maximum voluntary isometric contractions (MVlC's) based on a reliability study that was also conducted. The root mean of the squared differences (RMS difference) was used to compare the surface and intramuscular EMG waveforms. RMS difference was chosen as the best indication of predicability, as a quantitative assessment of amplitude difference was obtained using this method. The mean of the RMS difference values between surface and deep musculature in this study was 19.H %MVIC for the posterior aspect of the neck and 23.9 %MVIC for the posterolateral aspect of the neck. Due to the magnitude of difference between the surface and intramuscular EMG electrodes, it was concluded that EMG activity of the surface muscles docs not represent activity of deep musculature in the posterior and posterolateral aspects of the neck.

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