The effect of an orthotic device for balancing neck muscles during daily office tasks

Objective: This study aimed at evaluating the acute effect of the combined and single use of two orthotic devices (neck balance system [NBS] and lumbar support [LS]) on muscle activity of neck and back muscles during typical computer working tasks. Background: An excessive activation of neck muscles could threaten the balance between agonist and antagonist muscles, resulting in a lower stability of the head and possibly leading to neck pain. At present, no study evaluated the effect of a specific orthotic device in reducing neck muscles activation. Methods: Surface electromyography (sEMG) from neck flexor (sternocleidomastoid [SCMD]) and extensor muscles (semispinalis capitis [SPC]) and back extensor muscles (erector spinae [ERS]) of 20 healthy individuals was recorded during three computer working tasks performed with the NBS, with NBS and LS, with the LS, and without devices (ND). Results: In the NBS condition, the SPC showed a reduced activation (NBS = 3.97%; NBS + LS = 4.49%; LS = 4.48%; ND = 4.61% of the maximal voluntary contraction) compared to the other conditions. Conclusions: The use of the NBS promotes a reduction of neck extensor muscles, possibly due to the inertial mass added in the occipital part of the head, producing an external neck extensor moment that cooperates with that produced by neck extensor muscles. Application: Orthotic devices such as the NBS may be used by computer workers to reduce the activation of their neck extensor muscles and possible risks of developing neck pain.