  Impaired postural control has been reported in patients with chronic neck
pain of both traumatic and non-traumatic etiologies, but whether painful
stimulation of neck muscle per se can affect balance control during quiet
standing in humans remains unclear. The purpose of the present experiment was
thus to investigate the effect of experimental neck muscle pain on standing
balance in young healthy adults. To achieve this goal, 16 male university
students were asked to stand upright as still as possible on a force platform
with their eyes closed in two conditions of No pain and Pain of the neck
muscles elicited by experimental painful electrical stimulation. Postural
control and postural performance were assessed by the displacements of the
center of foot pressure (CoP) and of the center of mass (CoM), respectively.
The results showed increased CoP and CoM displacements variance, range, mean
velocity, and mean and median frequencies in the Pain relative to the No pain
condition. The present findings emphasize the destabilizing effect of
experimental neck muscle pain per se, and more largely stress the importance of
intact neck neuromuscular function on standing balance.
