Affiliations: [a] Bioengineering Research Group, School of Engineering, Cardiff University, Cardiff, UK | [b] Faculty of Health and Social Sciences, Bournemouth University, Bournemouth, Dorset, UK
Correspondence:
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Corresponding author: Peter S. Theobald, Bioengineering Research Group, Institute of Medical Engineering & Medical Physics, Queen's Building, The Parade, Cardiff CF24 3AA, UK. Tel.: +44 2920 874726; Fax: +44 2920 874716; E-mail:TheobaldPS@Cardiff.ac.uk
Abstract: BACKGROUND: The relationship between muscular force and electromyography (EMG)
has been investigated by numerous researchers. EMG has not previously been used as a
means of estimating force in the cervical erector spinae (CES). OBJECTIVE: Use EMG of the CES musculature to indirectly predict neck extension force. METHODS: Isometric contractions of the CES muscles were studied at increasing levels
of contractile force across all participants (n= 12) to produce an
individualised force-EMG relationship. The method of least squares was used
to determine the linear regression trend line for the force-EMG
relationship. The validity of these individual `correlation curves' was
demonstrated through further, blinded, investigation. RESULTS: A linear relationship was identified for the individualised correlation
curves that gained in strength for < 50% maximum voluntary contraction
(MVC; R2> 0.8 for 80% of trials). The prediction of muscle force from
the correlation curves was found to be statistically similar to the
equivalent experimental data (p> 0.05). Given the tendency of EMG to slightly
overestimate force in most cases, an adjustment coefficient was calculated
to reduce the error in the predicted force data. CONCLUSIONS: This study reports a validated method using EMG to indirectly
acquire CES muscular force, which has application for clinicians and research scientists
working in fields including sport and rehabilitation.
