These phenomena may concurrently
increase electromyographic activity of the cervical
musculature, such as neck extensor muscles and the levator
scapulae. In addition, the superficial muscles of the neckshoulder
region, i.e., the sternocleidomastoid, anterior scalene
and upper trapezius muscles, demonstrate increased
activities compared to deeper postural stabilizers like the
deep cervical flexors8)
. Moreover, several studies have reported
significantly lower maximal isometric strength of
both the cervical flexors and extensors in patients with
chronic neck pain compared to healthy controls9–11)
and one
study also found weakness of the neck rotator muscles12)
.
Recent studies have shown that the activities of the deep
cervical flexor muscles, such as the longus colli and longus
capitis, are impaired in persons with neck pain13)
. Furthermore,
the findings of a significant deficit in the ability to
maintain low or moderate load by the CCF muscles suggests
that head and neck postural orientation is challenged
under prolonged or repetitive circumstances in neck pain
patients. The CCF muscles may fatigue prematurely and be
incapable of controlling cranio-cervical orientation. This
potentially exposes cervical spine tissues to abnormal mechanical
load14)
. Indeed, evidence is emerging that persons
with neck pain tend to adopt a more forward head position
when distracted15)
. This has been observed despite a lack of postural differences in erect sitting16, 17)
. Moreover, retraining
the deep cervical flexor muscles has been shown
to decrease neck symptoms and increase the activation of
the deep cervical flexor muscles during performance of a
cranio-cervical flexion test18)
. This may improve the capacity
of the cervical spine to sustain an upright posture.
Physical exercise has been recommended as a treatment
for musculoskeletal neck disorders19, 20)
. While several
studies have demonstrated that pain can to some extent
be reduced by strength training19–22)
or endurance training21,
22)
, one study found no effect of physical training on
nonspecific pain in the neck area21)
. A recent review showed
limited evidence for the efficacy of physical exercise in the
treatment of symptoms of the neck and/or shoulder due to
the lack of high-quality research23)
. One meta-analysis concluded
that there was unclear and insufficient evidence in
support of the benefit of strengthening exercises for neck
pain24)
and the relative benefit of different exercise approaches,
such as cranio-cervical flexion of the deep cervical
flexor muscles. Although there is some evidence of pain
reduction occurring following strengthening, endurance or
cranio-cervical flexion exercise19, 20, 22)
, it is not known how
the training influences the muscle activities of persons with
chronic neck pain during working with a computer.