Influence of test position on neck muscle fatigue in healthy controls.
BACKGROUND
It has been suggested that increased fatigue of neck muscles could be related to neck pain. However, studies on the matter present contradicting results which could be explained by the different test positions used.


OBJECTIVE
The purpose of this study was to investigate the influence of test position on muscle fatigue of neck flexor and extensor muscles in healthy controls.


METHODS
Twenty-five women without neck pain sustained neck flexion and neck extension isometric contractions at 25% and 75% of their maximal voluntary contraction (MVC) in two test positions: sitting and supine lying. Using surface electromyography, the change over time of the median frequency of the power spectrum (MDF slope) of the myoelectric signal of the sternocleidomastoid and splenius capitis muscles was measured and compared between both positions.


RESULTS
At 75% MVC, splenius capitis muscles presented higher fatigue in lying compared to sitting, while sternocleidomastoid demonstrated no difference between positions. No statistically significant effect of test position was found at 25% MVC for both sternocleidomastoid and splenius capitis muscles as they generally did not present myoelectric manifestations of fatigue.


CONCLUSIONS
These results underline the need to standardise the test position when investigating neck muscle fatigue, especially for neck extensors at high loads.
School of Rehabilitation, Faculty of Medicine, University of Montreal and CRIR-Montreal Rehabilitation Institute, 6300 Darlington Ave, Montreal (Que.), Canada H3S 2J4. jean-louis.larochelle@umontreal.ca
Jean-Louis
JL
Larochelle
Maude
M
Laliberté
Martin
M
Bilodeau
Jean-Pierre
JP
Dumas
A
A
Bertrand Arsenault
D000328:Adult; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D012016:Reference Values; D055815:Young Adult