Reliability of normalisation methods for EMG analysis of neck muscles.
Acceptable reliability of normalisation contractions in electromyography (EMG) is paramount for testing conducted over a number of days or if normal laboratory strength testing equipment is unavailable. This study examined the reliability of maximal voluntary isometric contractions (MVIC) and sub-maximal (60%) isometric contractions for use in neck muscle EMG studies. Surface EMG was recorded bilaterally from eight sites around the neck at C4/5 level from five healthy male subjects. Subjects performed MVIC and sub-maximal normalisation contractions using an isokinetic dynamometer (ID) and a portable cable dynamometer with attached strain gauge (PCD) in addition to a MVIC against a manual resistance (MR). Subjects were tested in flexion, extension, left and right lateral bending and were retested by the same tester within a two-week period. Intra class correlation co-efficients (ICC) were calculated for each testing method and contraction direction and a mean ICC was calculated across all contraction directions. All normalisation methods produced excellent within-day reliability (mean ICC >0.80) but only the MVICs using the ID and PCD had acceptable reliability when assessed between-days. This study confirmed the validity of using MVICs elicited using the ID and PCD as reliable reference contractions for the normalisation of neck EMG.
School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia. K.Netto@curtin.edu.au
Kevin J
KJ
Netto
Angus F
AF
Burnett
D000328:Adult; D004576:Electromyography / Q000592:standards; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009334:Neck Muscles / Q000502:physiology*; D016272:Occupational Health; D012016:Reference Values; D014904:Western Australia