Muscle Performance in Neck Pain
- 1 Deep and superficial cervical muscle groups
- 2 Cervical muscle function in the presence of pain
- 3 Assessment
- 4 Rehabilitation
- 5 Resources
- 6 References
Deep and superficial cervical muscle groups
In the presence of neck pain and injury there is evident changes in muscle function in terms of motor control, strength, endurance, and patterns of activation.  The muscles affected will be listed below:
Deep cervical flexion muscles
- Longus capitis
- Longus colli (longus cervicis) - 3 portions: superior oblique, inferior oblique, vertical
- Rectus Capitis Anterior
- Rectus Capitis Lateralis
Superficial cervical muscles
- Levator scapulae
- Upper trapezius
- Splenius Capitis
- Splenius Cervicis
- Semispinalis capitis
- Semispinalis Cervicis
- Rectus capitis posterior major (Greater Posterior Rectus Capitis)
- Rectus capitis posterior minor
- Obliquus capitis superior
- Obliquus capitis inferior
Cervical muscle function in the presence of pain
- Reduced activity of the the deep cervical flexor muscles occurs together with an increase in activity and neuromuscular inefficiency of the superficial muscles even under low load and with non-functional tasks    This change in activation can be seen in functional as well as cognitive tasks and is not dependent on the cause or the duration of neck pain.  
- Patients with neck pain struggle to relax the superficial neck flexor muscles even after an activity has ceased. 
- These changes in muscle function occur soon after the pain started and do not automatically return to normal once the pain resolves. 
- Changes in function in the deep cervical muscles has an influence on function as it affects the support and control of the cervical spine and could lead to overload on specific segments 
- Research has shown that both the cervical flexors and extensors loose strength and endurance in the presence of neck pain  , and that co-activation of ceases especially with functional tasks. 
- Superficial cervical muscles will fatigue quicker
- Endurance is reduced in the cervical muscles for both maximal and low contractions 
- The feed forward activation is lost - this influences the timing of activation and can be seen when the patient is doing rapid arm movements.  When a patient without neck pain rapidly lifts his/her arm the cervical muscles will activate within 50ms of deltoid activation, in patients with neck pain there is a significant deficit for both the superficial and deep neck flexors which can result in an increase strain on the cervical spine. 
- Muscle atrophy occurs in the cervical muscles of patients with neck pain 
- Fatty infiltration has been identified in the deep flexor and extensor muscles of people with chronic whiplash associated disorder, but not in chronic insidious-onset of neck pain 
Motor control assessment of the longus capitis and colli activation and isometric endurance, while observing their interaction with sternocleidomastoid and anterior scalene muscles.
The PBU is positioned suboccipitally and then inflated to 20 mmHg. 
- The patient is instructed to move the head vertically (as if saying ‘yes’). The movement is performed gently and slowly . This nodding action causes the pressure in the inflated pressure sensor to increase. For the first stage of the test the pressure should increase by 2 mmHg to 22 mmHg while the superficial muscles stay relaxed.
- The patient is told to maintain this position for 10 seconds.
- Then the patient relaxes back to 20 mmHg to increase the pressure again this time to 24 mmHg using the same action and hold for five seconds. The patient has to do repeat this action until a pressure of 30 mmHg is reached.
Flexion of the neck requires activation of the deep cervical flexors. The superficial cervical flexors cannot be used to perform this movement. With each stage the range of motion should increase. Individuals who do not have neck pain will be able to hold the contraction for 10 seconds at stage 3 (26 mmHg) or higher. Someone with neck pain usually only reach stage 1 or 2 before they loose the neutral position or the superficial neck muscles contract. 
Neck Flexor Endurance Test
- Patient in supine position with knees bend. Patient has to tuck the chin (cranio-cervical flexion). The patient then has to lift the head 2.5 cm above the plinth while keeping the chin tuck position. 
- This test has good intra-rater reliability when used with patients with neck pain 
- The test was shown to be a reliable tool to measure the rehabilitation progress of a patient with neck pain
- Different studies have recorded times for this test
- Asymptomatic Men (mean = 25 seconds), asymptomatic woman (20 seconds) - (Olson et al. 20016)
- Asymptomatic Men (mean = 63.73 seconds), asymptomatic woman (38.43 seconds) - (Olson et al. 20016)
- Male patients with neck pain have a longer neck flexor endurance than females.
- Even though the duration times differ, multiple studies have found that men have a longer hold time than woman and that this should be considered when interpreting the test
- Asymptomatic group (mean = 39 seconds), group with neck pain (mean - 24 seconds) - (Harris et al, 2005)
Neck Extensor Endurance Tests
- The patient lies in prone with the head over the edge of the bed. The head could be supported on a stool with arms at the patient's side. The patient is then asked to do a chin tuck (cranio-cervical flexion) and hold the head steady in this position while the stool is removed. The patient has to maintain the head in a horizontal position. 
- Easy test to do because no tools are needed, however the test may take up valuable time that could be spent on other tests. 
- With patient in prone on elbows and the cranio-cervical region in neutral -test cervical extension of the deeper cervical group. Rotation can also be assessed in this position. 
Correlating the Neck Flexor Endurance Test with the Neck Extensor Endurance Test shows that the neck extensor muscles have significantly higher endurance than the neck flexor muscles in the neck pain population. These results are the same for acute to chronic neck pain patients through different ages. 
Muscle performance or muscle strength is “the ability of a muscle to produce force, regardless of the action (isometric vs. anisometric), load (body segment vs. free-weight), or intensity (‘low load’ vs. ‘high load’)". For a muscle to control a body segment it must first have sufficient strength.  To train muscle performance the muscle has to do a repeated action against some resistance (either the body segment or added weight), around a rotation axis in a single plane. This type of training has been shown to improve proprioception of that segment for e.g. when people with neck pain do a controlled head lift exercise. 
Early rehabilitation with patients should be emphasised and an exercise program should include both motor control and general strengthening of the neck muscles. 
Deep neck flexor training has been shown to reduce neck pain.  The CCF exercises was compared to passive mobilisation with assisted CCF in a study of 18 participants with chronic neck pain that were randomised in 2 intervention groups. Both groups showed decrease in pain relief but only the exercise group had improvement in motor function and decreased activation of the superficial neck flexors during the CCFT.  Endurance and strength training of the DNF muscles of a person with neck pain reduces the perceived neck pain of that patient. 
Stage 1 
- Cranio-cervical flexion (CCF) motor control should be retrained 
- Retrain the correct movement without activating the superficial muscles (the patient can place their hand on the muscles to feel when they contract)
- Train endurance of the deep neck flexors with the use of a pressure biofeedback.
- Functional training should be incorporated from the start and should be repeated throughout the day 
- The patient should try to “lift the base of their skull off the top of their neck in a neck lengthening maneuver” 
Stage 2 
Increase endurance and strength by increasing the load with added gravity during the head lift exercise.
- Patient is sitting with the head against the wall and does the Cranio-cervical flexion movement by sliding the head up the wall, the head is then moved just off the wall and held there for 10 seconds. Progress to 10 repetitions. The patient’s hands can be placed on the superficial muscles.
- Progress by moving away from the wall and repeating the exercise
- Progress to doing the exercise in supine and then in different body position
- Progress further by adding this movement in functional tasks specific to the individual including combined movements.
Stage 1 
- Patient prone on elbow or in a quadruped position depending on scapula control
- The patient starts with the head in cranio-cervical flexion and performs the following movements:
- cranio-cervical extension
- cervical extension (C2-C7)
- progressing to 3 sets of 10 repetitions through full ROM without fatigue
- while doing rotation and cervical extension the patient should keep the neck in cranio-cervical flexion - a way to cue the movement is to tell the patient to keep their eyes focused down (like looking down at a book) while doing the movements
- The patient starts with the head in cranio-cervical flexion and performs the following movements:
Stage 2 
- Adding load starting with 0.5kg. Neck specific resistance equipment could be used or weights could be added to something like a bike helmet.
Neck rotation proprioception and speed training
- Rayner & Smale Cervical Motor Control Part 1 - Clinical Anatomy of Cervical Spine. Physiotherapy blog sharing knowledge & encouraging growth.
- Deep Neck Flexor Stabilisation Protocol
- Brukner P. Brukner & Khan's clinical sports medicine. North Ryde: McGraw-Hill; 2012.
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- Rehab My Patient. Cervical Proprioception LASER Points In Range Rotation Eyes Open 2 Published on Aug 30, 2017 [Accessed 6 June 2018] Available from: https://www.youtube.com/watch?v=h-0ny-oJLXM
- Rehab My Patient. Cervical Proprioception LASER Points In Range Rotation Eyes Closed 2. Published on Aug 30, 2017 [Accessed 6 June 2018] Available from: https://www.youtube.com/watch?v=_mkveStrW8k
- Motion Guidance. Cervical Rotation Neck Proprioception Exercise with Motion Sensor. Published on Apr 23, 2018 [Accessed 6 June 2018] Available from: https://www.youtube.com/watch?v=EflMNYITmBw