Neck Solutions Blog

February 26, 2010

The effect of therapeutic exercise on activation of the deep cervical flexor muscles in people with chronic neck pain

Filed under: Chronic Pain, Neck Pain, Posture — Administrator @ 10:14 am

The effect of therapeutic exercise on activation of the deep cervical flexor muscles in people with chronic neck pain.

From: Man Ther. 2009 Dec;14(6):696-701. Epub 2009 Jul 25

Deep cervical flexor muscle activation is impaired with neck pain. This study investigated the effects of low load cranio-cervical flexion and neck flexor strengthening exercises on spatial and temporal characteristics of deep cervical flexor muscle activation during a neck movement task and a task challenging the neck’s postural stability.

Forty-six chronic neck pain subjects were randomly assigned to an exercise group and undertook a 6-week training program. Electromyographic activity was recorded from the deep cervical flexor muscle, sternocleidomastoid and anterior scalene muscles pre and post intervention during the cranio-cervical flexion test and during perturbations induced by rapid, unilateral shoulder flexion and extension. Cranio-cervical flexion neck exercises for training increased deep cervical flexor muscle electromyographic amplitude and decreased sternocleidomastoid and anterior scalene electromyographic amplitude across all stages of the cranio-cervical flexion test.

No change occurred in deep cervical flexor muscle electromyographic amplitude following strength training. There was no significant between group difference in pre-post intervention change in relative latency of deep cervical flexor muscle but a greater proportion of the cranio-cervical flexion group shortened the relative latency between the activation of the deltoid and the deep cervical flexor muscle during rapid arm movement compared to the strength group. Specific low load cranio-cervical flexion exercise changes spatial and temporal characteristics of deep cervical flexor muscle activation which may partially explain its efficacy in rehabilitation.

February 19, 2010

Lumbar spine movement patterns during prolonged sitting differentiate low back pain developers from matched asymptomatic controls

Filed under: Back Pain, Posture — Administrator @ 5:11 pm

Lumbar spine movement patterns during prolonged sitting differentiate low back pain developers from matched asymptomatic controls.

From: Work. 2010 Jan 1;35(1):3-14.

Little is known about how lumbar spine movement influences mechanical changes and the potential injurious effects of prolonged flexion associated with seated postures. The purpose of this study was to examine the postural responses and pain scores of low back pain sufferers compared with asymptomatic individuals during prolonged sitting in order to understand the biomechanical factors that may be associated with sitting induced low back pain.

Sixteen participants with sitting aggravated low back pain were age and gender matched with 16 asymptomatic participants. Tri-axial accelerometers were used to monitor lumbar spine angles during 90 minutes of seated computer work. Lumbar spine postures were examined using a movement pattern analysis of two types of postural adjustments, termed shifts (step-like adjustments larger than 5 degrees and fidgets (small change and return to approximately the same position).

The low back pain group reported large significant increases in low back pain while asymptomatic individuals reported little to no pain. On average, every participant fidgeted every 40 to 50 seconds. However, only the low back pain sufferers demonstrated a significant increase in the number of shifts over 90 minutes of seated work; the low back pain group shifted every 4 minutes in the last 30 minutes of sitting compared to every 10 minutes for the asymptomatic group. Low back pain sufferers also demonstrated larger amplitudes of shifts and fidgets when compared to the asymptomatic group.

Greater and more frequent movement was not beneficial and did not reduce pain in individuals with pre-existing low back pain. Future work to understand the biomechanical effects of proactively inducing movement may help to explain the paradox of the relationship between movement and pain.

Were the shift and fidget increases used to prevent further lower back pain. The article seems to relate sitting causes increased shifting and fidgeting in low back pain sufferers, however, the relationship is not clear. We note decreased pain associated with low back pain when using devices meant to increase movement like the backtivator and the active seat.

December 21, 2009

Backpack weight and postural angles

Filed under: Back Pain, Headaches, Neck Pain, Posture — Administrator @ 6:26 am

Effect of Backpack Weight on Postural Angles in Preadolescent Children.

From: Indian Pediatr. 2009 Oct 14

Backpack use is an appropriate way for carrying loads on the spine, closely and symmetrically, while maintaining stability. Students carry their educational loads mostly in backpacks, without the workplace standards that have been developed for adults. The daily physical stresses associated with carrying backpacks cause significant forward lean of the head and trunk. It is assumed that daily intermittent abnormal postural adaptations could result in pain and disability in school going children.

The peak rate of growth occurs during puberty and the growth of the appendicular skeletal system ceases around 16 years of age for females and 18 years for males. However secondary ossification of vertebrae is not complete until the mid twenties. Therefore, the spine may be susceptible to injury for a greater length of time and therefore, proper backpack use should be emphasized during these years. When the backpack load is positioned posterior to the body, the center of gravity shifts posteriorly, over the base of the support; the area covered by the feet. This shift is accomplished by either leaning forward at the ankle or hip or inclining the head and the rigidity of postural muscles controlling these adjustments increases to support the load. Children have relatively larger heads and also have higher center of mass at about T12, compared to L5-S1 in adults.

Carrying posterior loads by young people has been linked with spinal pain, and the amount of postural change produced by load carriage has been used as a measure of the potential to cause tissue damage. Back pain in children appears to be more common than was previously thought. Studies have indicated that 10%-30% of healthy children experience back pain, especially low back pain, by their teenage years. Hence, investigating postural responses to load carrying will help us to understand the impact of school backpacks on children.

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December 13, 2009

Correction of neck posture in computer users

Filed under: Neck Pain, Posture, Shoulder Pain — Administrator @ 6:39 am

Evaluation of a single accelerometer based biofeedback system for real-time correction of neck posture in computer users.

From: Conf Proc IEEE Eng Med Biol Soc. 2009;1:7269-72

There is sound evidence available showing the association between computer use and the risk of developing neck pain and musculoskeletal disorders. Consistent use of computers is one of the major risk factors for neck and shoulder disorders in the workplace. One of the most recent forecasts of computer adoption estimates that there were more than a billion computers in use at the end of 2008. This report also forecasts a 12.3% compound annual growth rate between 2003 and 2015. Driven by lower prices and global demand especially in developing countries it is expected that there will be over 2 billion computer users by 2015. A study of 512 office workers found the 12 month prevalence of neck pain to be 45.5%. Reports of the lifetime prevalence of neck pain in the general population range from 67-80%. As computer adoption increases we can expect a corresponding increase in the prevalence of neck pain if appropriate countermeasures are not employed.

Over time poor neck posture results in pain, muscle aches, tension and headache and can lead to long term complications such as osteoarthritis. Physiological and biomechanical stress due to sustained postures limit important musculoskeletal stimuli that are essential for normal musculoskeletal development. Most upper extremity disorders and symptoms (neck, shoulder, elbow and wrist pain) are associated with computer use at workstations in positions of poor posture. Along with the sitting position, placement of computer monitors and keyboards and the number of hours spent working at computer workstations are important factors in the etiology of cervical disorders associated with computer use. Other workplace risk factors include the number of hours per week of computer use and the time spent in a non-neutral posture at a computer.

A detailed survey at Harvard University showed that more then half of students experienced pain and discomfort while using a computer. The three factors significantly associated with computer-related upper extremity and neck pain among the students were female gender, eight or more years of using a computer 10 or more hours a week, and using a computer for more than 20 hours per week. Most of the students in the study reported that pain in the neck and upper extremity was related to computer use and the posture assumed while using a computer. Most of them adopted a better posture by adjusting the workstation and keyboard, while some took a break when feeling uncomfortable during their work on the computer. Workplace studies, of both cross-sectional and prospective design, consistently identified a relationship between the number of hours per week of computer use and musculoskeletal pain and disorders or the upper extremity and neck.

Trapezius Myositis/Spasm, Paraspinal/Rheomboid Spasm, Cervical Radiculopathy, Thoracic Outlet Syndrome, Bicipital Tendonitis, and Rotator Cuff Tendonitis are all common upper extremity and cervical musculoskeletal disorders associated with use of computers in poor posture. Tension neck syndrome and thoracic outlet syndrome are the most common problems associated with computer use and the major cause is prolonged sitting with the neck and back in flexed positions. These conditions are commonly reported for a person sitting in front of a computer for more then 4 hours which is common in office environments.

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October 21, 2009

Dynamic degenerative lumbar disc bulging

Filed under: Back Pain, Disc Problems, Posture — Administrator @ 1:25 pm

Dynamic Bulging of Intervertebral Discs in the Degenerative Lumbar Spine

From: Spine (Phila Pa 1976). 2009 Oct 16

The effect of postural change on degenerative lumbar discs was quantified using novel kinematic magnetic resonance imaging. The purpose is to describe the bulging of degenerative intervertebral lumbar discs in vivo subjected to different postural loads using a novel kinematic magnetic resonance imaging.

Symptomatic lumbar disc degeneration is a leading cause of pain and disability throughout the world. Over 70% of US citizens will experience a debilitating episode of low back pain. Earlier reports of degenerative disc changes are cadaver studies or are performed with recumbent MRI that eliminates the functional effects of gravity and muscle power. Little data are available on the behavior of degenerative intervertebral discs in vivo under physiologic loads.

A total of 513 patients obtained kMRI. Disc bulging beyond the intervertebral space was quantified during upright neutral, flexion, and extension imaging. The degree of intervertebral disc degeneration was correlated using the Pfirrmann Classification. Moderately degenerated intervertebral discs (grade III and IV) demonstrated greater bulging than mildly degenerated discs (grade II). Severely degenerated discs (grade V) also showed a trend toward greater bulging, but this was not significant. Grade I discs at all levels moved posteriorly in flexion and anteriorly in extension when compared to neutral posture. However, mild to severe (grade II-V) degenerative discs behaved differently in response to postural loads. Extension resulted in significant posterior bulging, while flexion did not demonstrate obvious anterior derangement.

Disc bulging increases with the severity of disc degeneration. Grade I discs demonstrate the expected sagittal migration in response to postural load. However, more degenerative discs behave less predictably, and spine extension may result in significant posterior disc bulging. Degenerative changes in the intervertebral disc significantly affect the kinematic patterns under postural load in vivo. Kinematic magnetic resonance imaging is a useful tool to quantify the kinematic behavior of degenerative intervertertebral discs.

September 17, 2009

Sustained mechanical loading and disc diffusion

Filed under: Back Pain, Disc Problems, Posture — Administrator @ 3:53 pm

2009 ISSLS Prize Winner: What Influence Does Sustained Mechanical Load Have on Diffusion in the Human Intervertebral Disc?: An In Vivo Study Using Serial Postcontrast Magnetic Resonance

From: Spine (Phila Pa 1976). 2009 Sep 14

An in vivo study of the effects of mechanical loading on transport of small solutes into normal human lumbar intervertebral discs using serial postcontrast magnetic resonance imaging (MRI) to investigate the influence of a sustained mechanical load on diffusion of small solutes in and out of the normal intervertebral disc.

Diffusion is an important source of disc nutrition and the in vivo effects of load on diffusion in human intervertebral disc remains unknown. Forty normal lumbar discs (on MRI) in 8 healthy volunteers were subjected to serial post contrast (Gadoteridol) 3 Tesla MRI in 2 phases. In phase 1 (control), volunteers were scanned at different time points – precontrast and 1.5, 3, 4.5, 6, and 7.5 hours postcontrast injection. In phase 2, 1 month later, the same volunteers were subjected to sustained supine loading for 4.5 hours. MRI scans were performed precontrast (preload) and postcontrast (postloading) at 1.5, 3, and 4.5 hours. Their spines were then unloaded and recovery scans performed at 6 and 7.5 hours postcontrast. In house software was used to analyze images.

Repeated-measures ANOVA and pairwise comparisons at different time points in the central region of the loaded disc compared to the unloaded discs revealed significantly lower signal intensity ratios indicating reduction in transport rates for the loaded discs. Signal intensity ratioscontinued to rise in loaded disc for 3 hours into recovery phase, whereas unloaded discs at the same time point showed a decrease.

Sustained supine creep loading (50% body weight) for 4.5 hours retards transport of small solutes into the center of human IVD and it required 3 hours of accelerated diffusion in recovery state for loaded disc to catch-up with diffusion in unloaded discs. The study supports the theory that sustained mechanical loading impairs diffusion of nutrients entering the disc and quite possibly accelerates disc degeneration.

September 12, 2009

gluteus medius weakness low back pain during pregnancy

Filed under: Back Pain, Posture — Administrator @ 10:15 am

Association between gluteus medius weakness and low back pain during pregnancy

From: Iowa Orthop J. 2009;29:97-9

This cross-sectional study examines whether there is an association between gluteus medius weakness in the presence of low back pain in pregnant women at any stage of gestation. Prevalence of low back pain during pregnancy is high, and identifying potential etiologies and targeted interventions is lacking. Thus, identification of an association between specific muscle weakness and pain would have clinical relevance. Initial pilot data suggests that weakness of the gluteus medius is strongly associated with the presence of low back pain during pregnancy.

Low back pain during pregnancy is considered a significant public health issue due to its high prevalence and associated health care costs. Prevalence ranges between 49-68.5% with up to one third of these women having pain that limits their ability to perform basic activities of daily living. Ten percent of women with chronic low back pain link the onset of their pain to pregnancy. Physical therapy literature and physical therapy clinical practice relating to low back pain in pregnancy has historically involved discussion of postural dysfunction, sacroiliac joint dysfunction, and “sciatica.” The authors of this proposal offer another possible correlation explaining back pain during pregnancy relating to gluteus medius performance.

It is the experience of the authors of this proposal that pregnant women routinely present to their physical therapy clinic with “radiculopathy” or “sciatica.” In fact, the incidence of herniated disc in pregnancy is actually quite rare (1%). Often, the physical exam does not reveal any neurologic findings indicative of radiculopathy, but instead reveals weakness and/or strain of the gluteus medius. Gluteus medius strain can present as low back pain either due to facet joint irritation relating to Trendelenburg gait, or can be referred pain from the gluteus medius itself. If a true neurologic weakness were present, one would expect to find both tensor fascia lata and posterior gluteus medius weak as they are commonly innervated (L5). Rather, in the authors experience weakness is specific to the gluteus medius. Foti et al. performed 3-dimensional gait analysis on 15 pregnant women during the second half of their pregnancy and again one year post-partum. Gait analysis includes both kinetic and kinematic parameters. The authors found significant changes in kinetic gait parameters during pregnancy, and offer this as an explanation for how
gait motion overall remains relatively unchanged. They found increased demand on the ankle plantar flexors, hip abductors, and hip extensors. Atrophied tissues, or weak muscles, are less tolerant of physical stresses applied. Pregnant women with weakness of the gluteus medius are therefore vulnerable for tissue injury—both because of the increased magnitude of stress applied (weight gain), and a decrease in stress tolerated before injury/strain.

Thus, the primary aim of this pilot study was to determine the association between weakness of the gluteus medius and the presence of low back pain during pregnancy.

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September 4, 2009

Postural responses in healthy seated individuals

Filed under: Neck Pain, Posture — Administrator @ 7:22 pm

A paradigm to assess postural responses triggered by anteroposterior translations in healthy seated individuals

From: Gait Posture. 2009 Aug 31.

Postural adjustments following mechanical perturbations have been studied in healthy seated humans. However, little is known on the minimal intensity that should be used to provoke a reaction. This knowledge could be essential to assess seated postural deficits in some pathological populations. The goal of the present study was to identify a low-intensity perturbation that could elicit postural reactions in healthy seated individuals.

Six healthy participants sat on an adapted ergonomic chair fixed on a moveable support surface that was submitted to forward and backward translations. The head and trunk kinematics as well as the activity of sixteen neck and trunk muscles were recorded. The head, arm and trunk center of mass was computed using kinematics and standard anthropometric tables. The authors found that ramp displacements with an acceleration profile reaching a maximal value of 1.17m/s(2) elicited reliable kinematic and electromyographic reactions across participants. Head and trunk segments initially responded opposite to the direction of translation, then reversed direction. Median peak-to-peak angular displacements in the neck, head and trunk, respectively, reached 3.6 degrees , 7.0 degrees and 7.1 degrees for forward translations, and 4.0 degrees , 8.2 degrees and 7.0 degrees for backward translations.

For forward translations, neck and trunk flexor muscles were activated first, followed by the extensor muscles, whereas for backward translations, extensor muscles were activated first, followed by flexors. Although this perturbation is of low-intensity compared to those typically used previously to evoke postural reactions, this stimulus is sufficient to elicit a reliable response. We suggest that such a perturbation could be used to assess the physical condition of individuals with neck injuries.

July 9, 2009

Postural changes in women with chronic pelvic pain

Filed under: Chronic Pain, Posture — Administrator @ 10:22 pm

Postural changes in women with chronic pelvic pain

From: BMC Musculoskelet Disord. 2009 Jul 7;10(1):82. [Epub ahead of print]

Among women, chronic pelvic pain is a highly prevalent (2% to 25%) clinical problem, with substantial costs as well as social and marital repercussions. Chronic pelvic pain is defined as continuous or recurrent pain in the lower abdomen or pelvis lasting at least six months, not related to pregnancy, and sufficiently severe to interfere with the habitual activities of the patient. Chronic pelvic pain excludes pain occurring exclusively in association with menstruation (dysmenorrhea) or during sexual intercourse (dyspareunia).

Although the etiology is often unknown, it may result from complex interactions among the gastrointestinal, urinary, gynecologic, musculoskeletal, neurologic and endocrine systems, as well as being influenced by psychological and sociocultural factors. To date, few therapeutic modalities have been effective in relieving the symptoms of chronic pelvic pain, particularly over the long term. An interdisciplinary approach has therefore been recommended, both to diagnose the presumed primary etiology, and to diagnose and control all the secondary factors associated with chronic pelvic pain.

In clinical practice, postural changes are frequently observed among women with chronic pelvic pain. Although this disease has been associated with musculoskeletal changes and particular postures, to date there have been no studies of the detailed postural evaluation of women with chronic pelvic pain, which can be performed by attending physicians, especially primary care physicians and gynecologists. Postural assessment can lead to early detection of uneven positions, shortenings, antalgic postures and tensions. Although these changes may not be the primary cause of the clinical condition, they can contribute significantly to the worsening of pain and tension. The authors therefore determined the frequency of postural changes in women with chronic pelvic pain, as assessed only by clinical examinations.

The authors observed statistically significant differences in the cervical spine and scapulae between women with chronic pelvic pain and control women. The authors believe that the changes observed in women with chronic pelvic pain resulted from a vicious cycle of pain and antalgic postures acquired over time. The mean duration of symptoms among women with chronic pelvic pain was about five years, and postural impairments over time can contribute significantly to the maintenance or worsening of pain. Nevertheless, the authors cannot conclude that women with chronic pelvic pain always show the same postural pattern. First, although the authors observed an association between chronic pelvic pain and postural changes, the control group, consisting of women who did not report any type of pain, also presented with several postural changes.

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July 1, 2009

Car driving and back support

Filed under: Back Pain, Posture — Administrator @ 9:43 am

Car driving with and without a movable back support: Effect on transmission of vibration through the trunk and on its consequences for muscle activation and spinal shrinkage

From: Ergonomics. 2009 Jul;52(7):830-9

The aim of this study was to test the effect of a movable backrest on vibration transmission through the trunk during driving and on the physiological consequences thereof. Eleven healthy male subjects drove for about 1 h on normal roads with a movable and with a fixed backrest (back support) while surface electromyography (EMG) was measured at the level of the fifth lumbar vertebra (L5) and vertical accelerations were measured at the seat, backrest and at the spine at the levels of the second sacral vertebra (S2) and seventh cervical vertebra (C7). The movable backrest significantly reduced accelerations at C7 by up to 11.9% at the 5 Hz frequency band. The movable back support also significantly reduced the coherence and transmission between S2 and C7 accelerations, but not the differential motion between these sensors. EMG at both sides of L5 was on average 28% lower when using the movable backrest. Spinal shrinkage was unaffected by backrest type. It is concluded that a movable backrest reduces the transmission of vibration through the trunk and that it reduces low back EMG. Car driving is associated with the risk of developing low back pain and this may be related to exposure to whole body vibration. This study found an effect of a simple ergonomics measure on the transmission of vibration through the trunk as well as on back muscle activation.

Interestingly, according to Ind Health. 2005 Jul;43(3):421-35

The addition of a back support causes stiffening of the body to limit the low frequency rocking motion of the upper body under x-axis motion, while considerable dynamic interactions with the backrest occur. The mean apparent mass (APMS) responses measured at the seat pan and the backrest suggest strong contributions due to the back support condition, and the direction and magnitude of horizontal vibration, while the role of seat height is important only in the vicinity of the resonant frequencies. In the absence of a back support, the seat pan responses predominate at a lower frequency (near 0.7 Hz) under both directions of motion, while two secondary peaks in the magnitude also occur at relatively higher frequencies. The addition of back support causes the seat pan response to converge mostly to a single primary peak, resulting in a single-degree-of-freedom like behavior, with peak occurring in the 2.7-5.4 Hz range under x-axis, and 0.9-2.1 Hz range under y-axis motions, depending upon the excitation magnitude and the back support condition. This can be attributed to the stiffening of the body in the presence of the constraints imposed by the backrest. A relaxed posture with an inclined backrest, however, causes a softening effect, when compared to an erect posture with a vertical backrest. The backrest, however, serves as another source of vibration to the seated occupant, which tends to cause considerably higher magnitude responses. The considerable magnitudes of the apparent mass response measured at the seat back under fore-aft motions suggest strong interactions with the backrest. Such interactions along the side-to-side motions, however, are relatively small. The results suggest that the biodynamic characterization of seated occupants exposed to horizontal vibration requires appropriate considerations of the interactions with the backrest.

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