From: Work. 2012 Jan 1;41(0):2591-5

This study aimed to evaluate the posture, muscle activities, and self reported discomforts of neck pain notebook computer users on three monitor tilt conditions: 100°, 115°, and 130°. Six subjects were recruited in this study to completed typing tasks. Results showed subjects have a trend to show the forward head posture in the condition that monitor was set at 100°, and the significant less neck and shoulder discomfort were noted in the condition that monitor was set at 130°. These result suggested neck pain notebook user to set their monitor tilt angle at 130°.

Man Ther. 2012 Feb 4. [Epub ahead of print]

There is considerable evidence that neck pain is associated with alterations in spatial and temporal behaviors of the neck muscles and changes in muscle properties. Changes have been identified in various neck and axio-scapular muscles and the neck flexors have received particular attention. There is some functional specificity between superficial and deep flexors. Superficial muscles, sternocleidomastoid and anterior scalenes are major contributors to flexion torque while deep neck flexor muscles (longus capitis and colli) have an important role in supporting the normal neck curve and segments in posture and movement.

Of clinical and functional relevance, reduced activation of the deep neck flexor muscles has been identified in association with increased activation of the superficial flexor muscles in studies using the cranio cervical flexion test in patients with a variety of neck disorders. The evidence of reduced deep neck flexor activity comes from laboratory studies using a direct measure of electromyographic (EMG) amplitudes. A number of clinical studies have limited measurement to sternocleidomastoid activity using surface EMG electrodes and have indirectly inferred reduced deep neck flexor function on the evidence of an inverse relationship between sternocleidomastoid, anterior scalenes and deep neck flexor muscle activity from laboratory measures of neck pain patients.

Training the deep neck flexor muscles is regarded as an important component of neck rehabilitation programs because of the functional importance of the deep neck flexor and the evidence suggesting that the altered pattern of activation between the deep and superficial flexors (1) does not correct automatically with pain relief and (2) persists without specific training. Many factors influence the magnitude of neck pain. It is uncertain whether changes in muscle function are a cause or effect of pain, but a relationship has been shown between neck pain intensity and activity in the deep (lesser) and superficial (greater) neck flexor muscles. Concomitantly, the degree of pain reduction in patients with chronic neck pain has a relationship with the change in deep neck flexor activity following training. Clinical trials also support the effectiveness of training the deep neck flexor muscles and restoring their normal temporal relationship with the superficial flexors as a component of a multimodal program for the rehabilitation of neck pain disorders.

Appropriate training methods are required to address the observed impairment in neck flexor muscle behavior in the clinical setting. Cervical flexor strengthening exercises such as a head lift regime, while improving strength, do not successfully address the altered pattern of activation between the deep and superficial neck flexor muscles but a motor relearning approach using low load exercises to target the deep neck flexors can do so. A common form of deep neck flexor muscle training involves the patient learning the cranio cervical flexion action and training the endurance capacity of the deep neck flexor in the supine position. Training in this way effectively redresses the altered behavior in the flexor synergy identified in the cranio cervical flexion test by increasing the measurable activity in the deep neck flexors and reducing the activity of sternocleidomastoid and anterior scalene muscles. From a clinical viewpoint, training in supine alone limits the number of repetitions that a patient can practice in a day. Repetition is an important feature in the motor learning process. Training in supine also is not functional and there is mixed evidence for the transfer of improvement in cervical flexor muscle performance to function with such training alone.

Facilitating an upright posture activates the longus capitis/colli group. Thus a postural correction exercise which can be performed easily during the working day is advocated within a training program. It is unknown whether training the deep neck flexor with a postural exercise is effective and can change the aberrant pattern of neck flexor muscle activity demonstrated in the cranio cervical flexion test. The purpose of this initial study was to investigate the effect of a postural exercise in a controlled trial of a 2-week intervention in the first instance. It was hypothesized that the postural exercise alone was sufficient to improve deep neck flexor muscle performance, indicated by a measureable decrease in sternocleidomastoid activity over progressive stages of the cranio cervical flexion test.

The exercise intervention consisted of a 2-week program in this preliminary study as a change in muscle behavior can be expected from a motor learning program in this period. The intervention began immediately after the baseline assessment for subjects allocated to the exercise group. The postural exercise was performed in sitting and required the subject to assume firstly, an upright posture in a neutral lumbo-pelvic position. They were then taught to gently lift the base of the skull from the top of the neck as if to lengthen the cervical spine. This neck lengthening manoeuvre strongly activated the longus colli. A neutral scapular position was taught if the scapulae were judged clinically for example, to be in a position of downward rotation or protraction. Subjects received training until it was assessed that they could perform the postural exercise properly. They were asked to perform the exercise, holding the position for 10s ideally every 15–20 min throughout their waking day, akin to a work break and exercise routine for the two week duration of the trial. Subjects were provided with an exercise diary to record the number of times the exercise was performed each day. Subjects returned twice in the two week period before the follow up assessment to ensure correct performance of the exercise and for motivation and compliance purposes.

Training with a functional postural exercise improved performance in the cranio cervical flexion test, measured in this study as a decrease in sternocleidomastoid activity. No change was observed in the control group. The pre to post-intervention analysis within the exercise group revealed decreased sternocleidomastoid EMG amplitudes at the first and third stages of the test with non-significant lower amplitudes in the other stages. The exercise involved assuming an upright neutral postural position with the addition of a neck lengthening manoeuvre. Both elements have been shown to activate the deep neck flexor. It can only be inferred from this study that the decrease in sternocleidomastoid activity in the cranio cervical flexion test was accompanied by an improvement in the activation of the deep neck flexor. Nevertheless this relationship was shown training the deep neck flexor in supine where reduced sternocleidomastoid activity in the cranio cervical flexion test was associated with an increase in deep neck flexor activity. Thus the authors hypothesis that the postural exercise can improve deep neck flexor muscle performance can be provisionally supported. However it is premature to comment on whether this exercise alone would be would be sufficient to address the altered behaviour of the neck flexor synergy in neck pain patients. Importantly, the results provide a justification for a larger study with direct measures of both sternocleidomastoid and deep neck flexor muscles using more invasive direct measures of deep neck flexor muscle activity.

Training the deep neck flexor in supine and achieved an increase in deep neck flexor and a decrease in sternocleidomastoid EMG amplitude across all cranio cervical flexion test stages, with the exception of the lowest level (22 mmHg). This could imply that training the deep neck flexor in supine is more effective. However it may merely reflect the longer training period (6-weeks) as opposed to the 2-week period in the present study. The 2-week training period was chosen for this preliminary study as a change in muscle behaviour could be expected in this time but future trials of the two methods would necessarily test equivalent periods of training. Alternately the results could be a product of the relatively small sample size of the current study. Nevertheless, the present study demonstrating a decrease in activation of the sternocleidomastoid post-intervention suggests, albeit indirectly, that a functional method of training the deep neck flexor in an upright position does lead to improvements in deep neck flexor activation. From a clinical viewpoint, a greater benefit may be achieved by combining both formal and functional methods of training in the management of patients with neck pain disorders. Future research is warranted to explore longer periods of training with the postural exercise alone against formal training in the supine position as well as the possible combination of these training methods in a management regime for patients with neck pain disorders.

The functional, postural exercise to improve cervical muscle performance is a suitable option to cater for the increasing number of people working in office environments or other sedentary occupations. Evidence of altered working postures such as increased forward head posture, implying poor function of the deep neck flexor, has been shown in those with neck pain. Improvements in the maintenance of neck posture during sustained sitting postures have been achieved with training the deep neck flexor in the supine position. A practical, time efficient exercise performed easily throughout the day, such as the postural exercise evaluated in this study, may prove an essential aspect for effective training of the deep neck flexor in those sedentary workers with neck pain. Judging by the compliance rate recorded in this study, the exercise is convenient to perform. On average, the exercise was performed 15 times per day, equating to approximately once per waking hour, or twice per productive day-time hour.

It appears important that patients are taught the postural exercise with precision as undertaken in this currently study. Deep neck flexor muscles were activated when subjects were merely instructed to sit in a good posture. However higher levels of activity were recorded in the deep neck flexor (and lumbar multifidus) when subjects were facilitated into an upright neutral lumbo-pelvic and spinal posture. This highlights the need for care in teaching and training a postural exercise in the rehabilitation of neck pain patients. Incorporating a specific neck lengthening manoeuvre in the postural exercise is likely to enhance the deep neck flexor contraction.

Two weeks of training with the postural exercise alone did not change pain and disability measures, which is not surprising. Only one exercise intervention was used, focusing on a single muscle group, which is inadequate and unrealistic given the potential extent of changes in cervical and axio-scapular muscle function in neck pain disorders. There is ample evidence from systematic reviews that clearly indicates that multimodal management is superior to any single modality in reducing neck pain and disability.

This study determined that training with a postural exercise consisting of assumption of a neutral lumbo-pelvic and spinal posture with an added neck lengthening manoevre led to an improved pattern of cervical flexor muscle activity in the cranio cervical flexion test. The improvement manifested as a reduced level of sternocleidomastoid activity, infering an increase in deep neck flexor activation post-training. While further research is necessary to explore the benefits of this exercise, these observations suggest the worth of including such an exercise in the rehabilitation of patients with neck pain disorders.

From: Man Ther. 2012 Jan 17. [Epub ahead of print]

Low back pain may be related to patterns of lumbar postures and movements used to perform different tasks, but it is unclear which patterns with which tasks contribute to low back pain. For example, increases in both lumbar flexion and extension have been linked to low back pain. Some studies have reported increased lumbar flexion in people with low back pain during activities involving flexion, such as golfing and cycling. Other studies have reported that increased lumbar extension is associated with low back pain during sitting. Inconsistent findings regarding the direction of increased lumbar movement or the presence of flexed versus extended postural alignment potentially associated with low back pain may be due to the inclusion of subjects with widely varying movement patterns in a single low back pain group. Several researchers have proposed that there are subgroups of people with low back pain whose symptoms are associated with different direction related postures or movement patterns (e.g., flexion or extension related).

If multiple low back pain subgroups are studied as a single population, differences between subgroups demonstrating patterns in opposite directions could average out to suggest no difference in motion between people with and without low back pain. When subgrouping was not included in the study design, several studies found no differences in lumbar postural alignment and motion between people with and without low back pain. Still other studies found that decreased lumbar motion is associated with low back pain. Lumbar postural alignment and motion characteristics associated with low back pain may be more clearly identified when people with low back pain are subgrouped based on lumbar patterns associated with symptoms.

Systems of subgrouping people with low back pain have allowed researchers to identify consistent differences in lumbar posture and motion between people with flexion or extension related low back pain symptoms and people without low back pain. Studies that subgrouped people with low back pain using O’Sullivan’s system reported that during typical sitting men with flexion related low back pain sat closer to their end range of available lumbar flexion compared to men without low back pain and that people in a flexion related subgroup sat in more lumbar flexion than people without low back pain and people in an extension related subgroup. Additionally, during slumped sitting, investigators found that people with extension related low back pain demonstrated less end range lumbar flexion than people with flexion related low back pain and people without low back pain. Finally, these investigators also found that people with extension related low back pain demonstrated less end range lumbar flexion during forward bending than people with flexion related low back pain. Investigators using the Movement System Impairment model for low back pain (Sahrmann SA. Diagnosis and treatment of movement impairment syndromes. St. Louis: Mosby, Inc; 2002) found that while there were no differences in standing lumbar alignment between people with and without low back pain, when subgrouped, people with low back pain in an extension related subgroup stood in more lumbar extension than people with low back pain in a flexion related subgroup and people without low back pain. Differences in end range lumbar flexion during flexion related tasks between subgroups based on the Movement System Impairment model have not been studied.

Low back pain may also be related to certain tasks. Some tasks, such as prolonged sitting and frequent forward bending, increase the risk of developing low back pain. However, the growing understanding of subgrouping suggests that the risk of low back pain may be influenced not only by what task is performed, but how high risk tasks are performed. The current study examines end range lumbar flexion during two common high risk tasks: slumped sitting and standing forward bending. End range lumbar flexion, as opposed to total lumbar flexion range of motion, was selected because the authors were only interested in the final position of the lumbar spine. Greater absolute amounts of lumbar flexion, regardless of an individual’s starting position, may indicate greater lumbar tissue laxity and a reduced ability of the passive structures of the lumbar spine to provide stability, particularly in resisting flexion. These tissue characteristics may place people at greater risk for tissue injury and pain. The specific tasks examined in the current study were chosen because they are both common flexion related tasks, but differ in the static versus dynamic nature of the task. The authors assessed the consistency of flexion related patterns across these tasks for two low back pain subgroups classified based on the Movement System Impairment model.

Differences in lumbar posture and motion between low back pain subgroups could be influenced by gender differences. Previous studies of differences in lumbar flexion between low back pain subgroups included more males in flexion related groups and more females in extension related groups. One study comparing people with flexion related low back pain to people without low back pain included only male subjects. The imbalance in gender distributions in past studies may have influenced the subgroup findings. In the back healthy population, it has been reported that men tend to adopt sitting postures and perform movements, such as forward bending, with greater lumbar flexion than women. Additionally, men tend to stand in more lumbar flexion and women in more lumbar extension. These findings suggest that, when there are uneven distributions of males and females, differences in posture and movement patterns between genders could influence differences found between low back pain subgroups. The current research will assess whether subgroup differences are independent of potential gender differences by incorporating comparable distributions of males and females within each subgroup.

The purpose of this study was to examine the effects of low back pain subgroup, classified based on the Movement System Impairment model, on lumbar end range flexion and symptom behaviour with a flexed posture (slumped sitting) and a flexion related movement (forward bending). The study included the two most prevalent of five low back pain subgroups studied to date: rotation and rotation with extension. The rotation subgroup demonstrates patterns of posture and motion and low back pain symptoms during tests associated with lumbar rotation, flexion, and extension. The rotation with extension subgroup demonstrates patterns of posture and motion and low back pain during tests associated with lumbar rotation, and extension, but not flexion. The authors predicted that the rotation subgroup would display greater end range lumbar flexion with slumped sitting and forward bending compared to the rotation with extension subgroup, and that the rotation subgroup would be more likely to report increased symptoms with both tasks than the rotation with extension subgroup. A secondary purpose was to examine differences in end range lumbar flexion between males and females and the effect of such differences on low back pain subgroup results. The authors predicted that males would show greater end range lumbar flexion than females, regardless of low back pain subgroup, and that gender effects would not be specific to either low back pain subgroup.

In this study, two low back pain subgroups, classified according to the Movement System Impairment model, demonstrated predictable differences in end range lumbar flexion across two flexion related tasks. Subjects in the rotation subgroup displayed significantly greater end range lumbar flexion during slumped sitting and a trend towards greater end range lumbar flexion during forward bending than subjects in the rotation with extension subgroup. Despite no differences between subgroups in current pain on the day of testing, the rotation subgroup was also more likely to report increased symptoms with both tasks than the rotation with extension subgroup. During both slumped sitting and forward bending, males displayed greater end range lumbar flexion than females; however, the subgroup differences identified were not the result of gender differences in end range lumbar flexion. Comparable distributions of males and females in each subgroup were used and no interactions between subgroup and gender on end range lumbar flexion were present. These findings support recommendations of subgrouping people with low back pain by demonstrating that subgroups of people with low back pain differ in amounts of end range lumbar flexion during tests of posture and potentially during movement.

The findings of the current study are consistent with previous research on slumped sitting and typical sitting. A prior study demonstrated that during slumped sitting, subjects in a flexion related low back pain subgroup sat in more end range lumbar flexion compared to an extension related low back pain subgroup. Prior studies also demonstrated that during typical sitting, subjects in a flexion related low back pain subgroup sat in more lumbar flexion compared to an extension related low back pain subgroup. The results of the current study are also consistent with others’ observations of end range lumbar flexion during forward bending in people with low back pain. Subjects in a flexion related low back pain subgroup had greater end range lumbar flexion with forward bending compared to subjects in an extension related low back pain subgroup.

The current study also indicates that gender is a factor in end range lumbar flexion during flexion related tasks. The findings are consistent with research on back healthy subjects showing males adopt greater lumbar flexion than females during prolonged sitting and that males have greater lumbar flexion and less hip flexion compared to females during forward bending and a reaching task involving forward bending. In the current study, a similar relationship between lumbar flexion exhibited by men and women during slumped sitting and forward bending was also evident in people with low back pain.

One possible reason for differences in end range lumbar flexion between genders and subgroups could be differences in hip movement. During forward bending, reduced hip flexion might contribute to greater end range lumbar flexion. This could explain differences between males and females observed in this study, where greater lumbar flexion corresponded to reduced hip flexion for males compared to females. It is logical that decreased hamstring flexibility could limit hip flexion motion during forward bending, thereby encouraging greater lumbar flexion to compensate. Studies of healthy individuals have demonstrated that males have reduced hamstring flexibility compared to females. Although there is some evidence to suggest a relationship between reduced hamstring flexibility and decreased pelvic or hip flexion during forward bending in healthy individuals and in people with low back pain, the evidence regarding the relationship between hamstring flexibility and lumbar flexion is equivocal and the studies are limited methodologically. On the other hand, the amount of hip flexion may not influence differences in end range lumbar flexion between subgroups. There were differences in end range lumbar flexion between subgroups, but not in end range hip flexion during forward bending. This may suggest that hip flexibility affecting lumbar motion is not the main issue differentiating subgroups, but rather the issue may be related to the consistent demonstration of lumbar flexion across tasks.

The finding of differences in end range lumbar flexion between genders and subgroups across two different flexion related tasks provides some support to the proposal that people adopt directional, stereotypic patterns of posture and movement. The frequent use of a limited repertoire of stereotypic posture and movement patterns used across many daily activities could lead to microtrauma to lumbar region tissues. It has been proposed that a cycle of spinal ligament subfailure leading to changes in neuromuscular control and subsequent tissue injury plays a role in low back pain. Repeated use of end range flexion across many tasks could potentially result in tissue changes that reduce spinal stability and put people at risk for tissue damage, injury, and pain. For flexion related low back pain subgroups, during postures maintained for long periods of time (e.g., slumped sitting), passive structures could lose their ability to support the spine. During movements that take the lumbar spine into a great amount of lumbar flexion (e.g., forward bending), the combination of stereotypic movement patterns involving exaggerated end range flexion and tissue laxity from prior exposure to flexion postures could promote greater repeated use of certain tissues and further injury to the lumbar spine.

The current study lends support to the proposal that repeated adoption of end range lumbar flexion during many tasks may put people at greater risk for pain during flexion. The rotation subgroup, which showed a pattern of greater lumbar flexion during slumped sitting and forward bending than the rotation with extension subgroup, were more likely to report symptoms during both tests. However, males, who showed greater lumbar flexion during slumped sitting and forward bending than females, were not more likely to report symptoms during either test. Differences in symptoms during both slumped sitting and forward bending found between subgroups, but not between genders, suggest that increased end range flexion values alone do not directly correspond to an increased likelihood of low back pain symptoms. The authors would propose that the interaction of increased end range motion, paired with decreased movement variability across activities and an increased likelihood of performing repeated end range motions, is what sets a person up to develop pain. For the rotation subgroup, avoiding lumbar flexion, particularly end range lumbar flexion, may be an important component of treatment.

The results of this study add further evidence suggesting a link between low back pain and lumbar posture and movement patterns. A greater understanding of the mechanisms that contribute to low back pain development, persistence, and recurrence can provide information to guide preventative and rehabilitative treatments for low back pain. Subgrouping people with low back pain may allow for treatments that target the posture and movement patterns most related to symptoms. Treatments emphasizing modifying lumbar movement patterns based on low back pain subgrouping are showing promise. Additional research on low back pain subgroups can provide further insight into the posture and movement patterns that contribute to low back pain and how this information can be used to improve the care of people with low back pain.

People in the rotation subgroup displayed more end range lumbar flexion during slumped sitting and forward bending than people in the rotation with extension subgroup. Men displayed greater end range lumbar flexion than women during both slumped sitting and forward bending. Differences found between subgroups, however, were not related to gender differences. These results support the proposal that people with low back pain display stereotypic patterns of posture and movement. They also support the need for subgrouping people with low back pain based upon patterns of posture and movement and symptoms consistently displayed across tasks. An increased understanding of differences between subgroups of people with low back pain is necessary to understand what contributes to low back pain problems and to guide preventative and rehabilitative treatment strategies.

Source: Differences in end range lumbar flexion during slumped sitting and forward bending between low back pain subgroups and genders

From: Work. 2012 Jan 1;41(1):99-108

This study examined the effects of various backpack loads on elementary schoolchildren’s posture and postural compensations as demonstrated by a change in forward head position. A convenience sample of 11 schoolchildren, aged 8-11 years participated. Sagittal digital photographs were taken of each subject standing without a backpack, and then with the loaded backpack before and after walking 6 minutes (6MWT) at free walking speed. This was repeated over three consecutive weeks using backpacks containing randomly assigned weights of 10%, 15%, or 20% body weight of each respective subject. The craniovertebral angle was measured using digitizing software, recorded and analyzed.

Subjects demonstrated immediate and statistically significant changes in craniovertebral angle, indicating increased forward head positions upon donning the backpacks containing 15% and 20% body weight. Following the 6MWT, the craniovertebral angle demonstrated further statistically significant changes for all backpack loads indicating increased forward head postures. For the 15 & 20% body weight conditions, more than 50% of the subjects reported discomfort after walking, with the neck as the primary location of reported pain. Backpack loads carried by schoolchildren should be limited to 10% body weight due to increased forward head positions and subjective complaints, primarily neck pain, at 15% and 20% body weight loads.

From: Ergonomics. 2012 Jan;55(1):87-102

The objective of this study was to measure the effect size of three important factors in manual material handling, namely expertise, lifting height and weight lifted. The effect of expertise was evaluated by contrasting 15 expert and 15 novice handlers, the effect of the weight lifted with a 15-kg box and a 23-kg box and the effect of lifting height with two different box heights: ground level and a 32 cm height. The task consisted of transferring a series of boxes from a conveyor to a hand trolley.

Lifting height and weight lifted had more effect size than expertise on external back loading variables (moments) while expertise had low impact. On the other hand, expertise showed a significant effect of posture variables on the lumbar spine and knees. All three factors are important, but for a reduction of external back loading, the focus should be on the lifting height and weight lifted.

The objective was to measure the effect size of three important factors in a transfer of boxes from a conveyor to a hand trolley. Lifting height and weight lifted had more effect size than expertise on external back loading variables but expertise was a major determinant in back posture.

Man Ther. 2011 Aug;16(4):394-8.

Static balance tests using posturography and force plates have been used to identify and evaluate postural stability in subjects with persistent whiplash and postural stability deficits in various stance and visual conditions have been found in these patients. Subjects with persistent whiplash also commonly report dizziness and or unsteadiness (70%) and complain of episodes of loss of standing balance (48%) and of actual falls (21%). Subjects who report these symptoms have also demonstrated greater deficits in static standing balance when compared to those who don’t report these symptoms. It is thought that these symptoms are a direct result of the cervical injury although vestibular damage is also possible.

The disturbances in static standing balance seen in patients with trauma induced persistent neck pain, may contribute to consequent difficulties in the completion of dynamic and functional balance tasks but to date there has only been one other study to look at some functional and dynamic measures and they demonstrated altered trunk angular velocity and sway angle during the tests in a whiplash compared to a control group. Simple and easy to conduct dynamic and functional balance tests using clinical measures with minimal equipment are thought to more adequately evaluate performance on the types of tasks in which falls may potentially occur.

Such clinical measures of dynamic and functional tests have been used in the assessment of balance in subjects with neurological and vestibular conditions and recently some tests have been measured in an elderly population with neck pain, where the dynamic balance measures were found to be impaired in addition to force plate evaluations of static balance. The findings suggested that neck pain in the elderly contributes to disturbance in balance and gait parameters over and above that which occurs with normal ageing. Specifically, a slower self-selected gait speed and cadence when walking with side to side head turning, and a significantly longer gait cycle duration when walking both without and with head turns was observed when compared to healthy control subjects. Dynamic balance deficits have also been found in subjects with unilateral vestibular loss in the step test, tandem walk and Dynamic Gait Index.

The aim of this pilot study was to determine whether postural stability differed between subjects with persistent whiplash and healthy controls in selected clinical dynamic and functional balance measures.

This pilot study supports that neck pain following a traumatic injury is associated with deficits in dynamic and functional balance tasks. The whiplash subjects demonstrated significant impairments in selected clinical measures in comparison with healthy control subjects. The tasks that the whiplash group had difficulties with were the step test, timed 10 m walk test both with and without head movement, tandem walk test forwards and backwards on both firm and soft surfaces, and the stair walking test. The whiplash group also lost stability significantly more quickly in the single leg stance test with eyes closed than the control group. These findings generally support the results of a previous study.

A test of dynamic single leg stance, the step test demonstrated significant differences between the whiplash and control groups that reflected those found in the single leg stance measures with eyes closed. The tandem walk test also demonstrated significant differences between the whiplash and control groups. These differences strengthen the consensus in the literature that persistent whiplash is associated with deficits in static balance, particularly when vision is altered and or a decreased base of support is provided. Similar findings were found in subjects with unilateral vestibular loss compared to healthy control subjects in single leg stance with eyes closed, tandem walking, the step test and Dynamic Gait Index.

In the timed 10 m walk test, the whiplash group had a significantly slower self-selected fast gait speed and took more steps in the 10 m without head turns, which was even more considerable with head movement from side to side and up and down. Similar findings for gait speed and number of steps with head turns were evident in elderly subjects with neck pain.

The stair walking test demonstrated significant differences between the whiplash and control groups with the whiplash group significantly slower, climbing fewer stairs in the 2 min period. In addition to functional balance, this test may also have been indicative of cardiovascular fitness in these subjects. Nevertheless there was a moderate correlation between the stair walking test and both neck pain and disability and dizziness handicap. Thus pain and disability and dizziness could also have been contributing factors. It may be of interest to examine all potential factors in a future investigation.

The Fukuda stepping test and Singletons test were measures of dynamic and functional balance which did not demonstrate any differences between groups. In contrast, the Fukuda stepping test demonstrated a significant difference in the angle of rotation from the midline between subjects with unilateral vestibular loss and healthy controls. However, in this study discriminating ability of the test could be questioned as the normal subjects performed at a level which would be considered to be positive for vestibular dysfunction or asymmetry. Similar findings in a recent study looking at patients with chronic dizziness screening for peripheral vestibular asymmetry, suggested that the test might not be a reliable screening tool. Others however have found disturbances in the Fukuda stepping test in a percentage of patients with whiplash but used sophisticated technology to track head movement during the test. Further research is required.

There are some limitations to this study. Subject numbers were relatively low and unfortunately the examiners were not blinded to the groups. Nevertheless the sample size calculation was based on the difference between narrow stance eyes closed balance test determined from idiopathic neck pain and asymptomatic control subjects. Idiopathic neck pain subjects have been found to generally have less balance disturbances than whiplash patients and thus the sample size of 20 used in this study was thought to be sufficient to detect functional balance disturbances.

Further, blinding of the study is likely to be difficult due to the likely neck pain and balance impairments of the clinical participants making them distinct from the control group.

Despite relatively small subject numbers, the results of this study suggest that subjects with persistent whiplash demonstrate disturbances in selected clinical dynamic and functional balance tasks. These disturbances are likely attributable primarily to altered cervical somatosensory input leading to impaired postural stability although the possibility of primary or secondary vestibular pathology should also be considered and it is possible that subjects with undiagnosed primary and or secondary vestibular pathology following a whiplash injury were included in this cohort. The results suggest that subjects with higher levels of pain and disability and dizziness handicap may have greater deficits as significant moderate correlations were seen between dizziness handicap and measures of tandem walk, stairs and walking without head movement and between neck disability and measures of tandem walk, stairs and walking with and without head movement. This is interesting as previous studies have found very few correlations between reported neck pain and disability and dizziness handicap and static balance measures. Dynamic and functional tests are thought to more adequately evaluate falling risk than static balance measures and thus might also be a better indicator of postural stability impairment and associated complaints in those suffering from a whiplash injury. Further research will be required to examine any relationship between pain and dizziness.

The findings of this pilot study may have implications for the assessment and management of balance in those with persistent whiplash. The relatively young whiplash subjects in the current study were performing at levels similar to healthy elderly control subjects over 65 years (18) which possibly will have implications for the future as they age and may deteriorate further. Thus there is a need for further research in a larger cohort. If the findings are confirmed, consideration of a comprehensive assessment of mobility and dynamic balance tests and subsequent management will be important. From a clinical perspective, the preliminary results indicate that a battery of dynamic and functional balance tasks, especially walking with head movement, steps, stairs and tandem walking; might need to be included in the routine examination of all whiplash patients. In this study, the majority of the subjects (70%) complained of some level of dizziness handicap and due to the moderate correlations between neck pain and disability and dizziness handicap and most of the measures, it is hypothesised that persistent whiplash subjects with higher levels of neck pain and disability and dizziness handicap may exhibit greater deficits and this should also be examined in future research.

Future research should consider the influence of presence of dizziness, reported loss of balance and falls on dynamic and functional balance measures in subjects with persistent whiplash. Other commonly used clinical dynamic and functional balance tests, such as the dual task timed up and go test may also be useful to examine in subjects with persistent whiplash. It will also be important to assess the onset of these problems and incidence in those with an acute whiplash injury.

Reference: Standing Balance In Persistent Whiplash A Comparison Between Subjects With And Without Dizziness

From: Clin Biomech (Bristol, Avon). 2011 Oct 18. [Epub ahead of print]

Previous studies reported that, in non-degenerate discs, the nucleus pulposus migrates posteriorly during flexion and anteriorly during extension within the intervertebral disc. However, in these studies the differences between anterior and posterior distances have been regarded as an indicator of nucleus pulposus migration. This study investigated the reality of migration of the nucleus pulposus within the intervertebral disc with changing postures.

Magnetic resonance images were obtained of the lumbar spines of 25 asymptomatic volunteers in sitting, standing and supine postures. The anterior and posterior height of the intervertebral disc, the anterior-posterior length of the intervertebral disc and nucleus pulposus, and the positions of the anterior and posterior margins of the nucleus were measured from mid-line sagittal images.

Changing postures altered the anterior and posterior height of the disc and three types of morphological changes, including changes in the anterior-posterior lengths of the intervertebral disc and nucleus pulposus, together with the position of the nucleus in the disc were found. The length of the intervertebral disc and nucleus pulposus changed under the variations in spinal loading caused by posture.

The results of this study indicated that the apparent nucleus pulposus migration within intervertebral disc is actually deformation of the nucleus pulposus length which depends on posture and the magnitude of the load. In other words, adopting different postures deforms the nucleus pulposus and therefore, changes the position of the nucleus pulposus but there is no apparent nucleus pulposus migration within the intervertebral disc.

From: J Pain Res. 2011;4:287-96.

The purpose of this study was to evaluate a multidisciplinary, interventional, ergonomic education program designed to reduce the risk of musculoskeletal problems by reducing schoolbag weight and correcting poor sitting posture.

Data were collected twice before and twice following intervention using the Standardized Nordic Body Map Questionnaire, a rapid upper limb assessment for posture evaluation, and schoolbag weight measurement in children aged 8 and 11 years attending two schools within the central region of Malaysia.

Students who received the ergonomic intervention reported significant improvements in their sitting posture in a classroom environment and reduction of schoolbag weight as compared with the controls.

A single-session, early intervention, group ergonomics education program for children aged 8 and 11 years is appropriate and effective, and should be considered as a strategy to reduce musculoskeletal pain among schoolchildren in this age group.

From: Front Physiol. 2011;2:64. Epub 2011 Sep 21.

Piercings (body art, i.e., with jewelry) are more and more widespread. They can induce various complications such as infections, allergies, headaches, and various skin, cartilage, or dental problems, and represent a public health problem. We draw attention to possible side effects resulting from face piercing complications observed on four young adults such as eye misalignment, decreased postural control efficiency, and non-specific chronic back pain with associated comorbidity. The authors found that the origin was pierced jewelry on the face. Removing the jewelry restored eye alignment, improved postural control, and alleviated back pain in a lasting way.

The authors suggest that pierced facial jewelry can disturb somaesthetic signals driven by the trigeminal nerve, and thus interfere with central integration processes, notably in the cerebellum and the vestibular nucleus involved in postural control and eye alignment. Facial piercings could induce sensory-motor conflict, exacerbate, or precipitate a pre-existing undetermined conflict, which leads pain and complaints. These findings are significant for health; further investigations would be of interest.

For face pierced jewelry, it is important to emphasize that trigeminal primary afferent neurons and their sensory receptors provide information for the perception of the orofacial region, and contribute to various types of sensorimotor integration such as postural control while quiet standing. These afferences project to the cerebellum, the reticular formation, and the vestibular nucleus which are located at the base of the spinal motor neurons and oculomotor efferents.

Body piercings with jewelry, at least on the face, could more or less rapidly induce other complaints than the medical complications described in the relevant literature; the authors report here body pain, impaired postural control, and vertical eye misalignment (heterophoria). If these side effects were confirmed in a larger population, health professionals need to deal with them taking into account sociological and psychological aspects. The authors hope this study of a few cases could stimulate further experimental and clinical research to complete the investigation on risk factors linked to body piercing, and lead to public health recommendations and prevention. More knowledgeable clinicians could thus better inform patients thus helping to reduce possible future complaints.

Health professionals and researchers should be aware of the possible side effects of piercings, i.e., impaired motor control, body pain, and additional comorbidity – known in chronic back pain including postural disorders, and the presence of vertical heterophoria.

From: Man Ther. 2011 Sep 24. [Epub ahead of print]

Reduced cervical range of motion is a common finding in people with neck pain. Exercises targeting cervical range of motion has also been recommended for this patient group. In research, different methodologies for range of motion measurements have been used, but with a few exceptions, only the angle between head and thorax has been measured. Thus, the neck has been modelled as one joint.

The upper and lower parts of the cervical spine differ substantially with respect to the biomechanics. In addition, specific diagnoses, such as cervicogenic headache, have been linked to dysfunctions in the upper cervical segments. Also the lower cervical segments may be the source of neck pain in some patients.

Thus, objective measures of cervical range of motion that can separate the movement of the upper and lower cervical spine can be valuable for characterisation of patients and treatment evaluation. A simple method for separating upper and lower cervical levels in flexion-extension has been used for other kinematic investigations. In this method the thorax, cervical spine and head form a three-segment model that allows measurement of flexion and extension at the upper and lower cervical levels. The first aim of this study was to use such a model to compare active cervical flexion and extension, separate for upper and lower cervical levels, between people with chronic neck pain and controls.

Despite the wide use of range of motion tests in studies on neck pain, few researchers have studied relationships between the degree of restriction of range of motion and self-rated disability. Therefore, the second aim was to investigate associations between range of motion measures of flexion-extension and self-rated characteristics such as health, functioning and symptoms. In addition, the authors investigated associations between axial range of motion and self-rated characteristics since axial rotations are important in many functional tasks.

Recent research indicates that people with neck pain and concurrent low back pain can have greater impairments in sensorimotor functions than people with neck pain without concurrent low back pain. Neck pain conditions with concurrent low back pain have also been identified as more treatment resistant than localised pain conditions. This highlights the importance to account for generalised spinal pain in studies on neck pain. Thus, a third aim was to compare cervical range of motion between people with neck pain with and without concurrent low back pain.

The authors have investigated active cervical range of motion in flexion-extension with a three-segment model and found that in the upper cervical spine extension was more reduced than flexion whereas predominately flexion was reduced in the lower levels in subjects with neck pain compared to controls. In the neck pain group, the degree of reduced range of motion in flexion-extension as well as in axial rotation was associated to greater self-reported head movement related problems, activity limitations, symptoms and lower physical activity. The authors found no differences in range of motion between neck pain subjects with and without concurrent low back pain.

The finding of reduced sagittal and axial range of motion for the neck pain group was expected and in line with several other studies. The main novel contribution of this study was that the authors studied flexion/extension separately for upper and lower levels of the cervical spine. The authors found that range of motion was, in absolute terms (i.e., in degrees), more reduced for the upper than for the lower cervical levels in the neck pain group compared to the control group. However, when they analysed the upper cervical range of motion in relation to the lower, they found that the ratio between range of motion for the upper and lower levels was altered in neck pain so that the lower levels contributed to a lesser extent to the total sagittal range of motion compared to controls. The greater relative reduction in range of motion for the lower levels could reflect an unwillingness to flex and extend the lower cervical levels, since that would cause a greater centre of mass migration of the head and thus increase the torque in the cervical spine. This is in line with recommendations of training control of the cervical spine from a seated posture in which the range of active extension is gradually increased to improve control of the craniocervical flexors. This is however a tentative explanation and other causes are possible.

These results show that a three-segment model gives more information than a two-segment model and gives valuable information in characterising range of motion impairments.

The impairments of range of motion in neck pain were mainly limited to extension for the upper cervical levels and flexion for the lower cervical levels. This direction specific difference between the levels could have been caused by group differences in the subjects’ self-selected seated posture since we used that posture to define zero flexion/extension. For example, a more protracted head in the starting position could lead to a reduced range of motion in extension for the upper cervical spine and a reduced range of motion in flexion for the lower cervical spine. Previous studies have reported a forward head posture in people with neck pain. A post hoc analysis of the starting position showed a trend for a group difference between control and neck pain for the CV-angle. Since a forward head posture likely would influence the symmetry of flexion/extension, they adjusted the analysis of group differences of range of motion for the CV-angle. The fact that the interactions group direction were significant with CV-angle as a covariate shows that the directions specific differences between groups could not be explained by a forward head posture but must also have other origins. For the lower levels, this could simply reflect that range of motion was substantially greater in flexion than in extension leaving little room for a reduction in extension. The reduced range of extension for the upper levels in the neck pain group may reflect a habituated sitting posture including a more extended upper cervical spine. Such posture could result from impairments of the deep cervical flexors in people with neck pain since there is evidence that reduced cross-sectional area of the deep flexor longus colli is associated with a greater lordosis of the cervical spine. In the present study they could however not control for the degree of extension in the upper cervical spine in the starting position since they didn’t anchor the head segment in an anatomically standardised way.

The analyses of associations between range of motion variables and self-rated functioning and symptoms showed that the cross-validated explained variance of the range of motion variables were modest (8–13%) and the Spearman’s rank correlation coefficient were at most moderate. Rrange of motion has great natural variability in healthy controls, which is apparent from the descriptive statistics. The variability in the neck pain sample can be seen as a sum of this natural variability and variability due to the pathology. When interpreting the modest associations the great natural variability in range of motion should therefore be taken into account.

The authors found significant predictors in 4 different categories: ratings of head movement impairments, activity limitations, symptoms and physical activity. In general, the predictors were weak. Head movement impairments appeared to have slightly stronger associations to reduced range of motion compared to the other predictor categories. Pain intensity during activities for the last 7 days was correlated to reduced range of motion in flexion, extension and axial rotations. This study found significant predictors in the symptoms category is in line with this finding.

The authors found no differences between subjects with neck pain with or without concurrent low back pain for any of the range of motion measures. This is in contrast to results showing greater reduction in peak speed of axial head rotations and greater postural sway in subjects with neck pain and concurrent low back pain compared to those without low back pain. This contrast is strengthened by the fact that the data for these three studies were collected in the same sample at the same test occasion. This discrepancy may be related to that quiet upright standing and fast head movements puts greater demands on trunk stability than does self-paced range of motion movements. This difference together with the fact that low back pain has been associated with impairments in sensorimotor function of the trunk muscles may provide an explanation for the differential effect of concurrent low back pain in these tests.

The associations between reduced range of motion and greater head movement related problems, activity limitations and symptoms support the clinical validity of the range of motion test when evaluating treatment effects on neck pain.