Reproducibility and instrument validity of a new ultrasonography-based system for measuring cervical spine kinematics

Scalable musculoskeletal model for dynamic simulations of upper body movement

A musculoskeletal (MSK) model is a valuable tool for assessing complex biomechanical problems, estimating joint torques during motion, optimizing motion in sports, and designing exoskeletons and prostheses. This study proposes an open-source upper body MSK model that supports biomechanical analysis of human motion. The MSK model of the upper body consists of 8 body segments (torso, head, left/right upper arm, left/right forearm, and left/right hand). The model has 20 degrees of freedom (DoFs) and 40 muscle torque generators (MTGs), which are constructed using experimental data. The model is adjustable for different anthropometric measurements and subject body characteristics: sex, age, body mass, height, dominant side, and physical activity. Joint limits are modeled using experimental dynamometer data within the proposed multi-DoF MTG model. The model equations are verified by simulating the joint range of motion (ROM) and torque; all simulation results have a good agreement with previously published research.

A new system to measure the trunk angle and pelvis angle during wheelchair propulsion

BACKGROUND

The number of wheelchair users is increasing as the population ages. However, there is still lack of tools to objectively assess posture during wheelchair propulsion.

OBJECTIVE

The purpose of this study was to develop a system to measure trunk and pelvis ROM (range of motion) while driving a wheelchair and to assess the reproducibility of the measured posture changes and cyclic fluctuations during propulsion.

METHODS

Motion recorders were attached to the sternum and pelvis of fifteen healthy adults, and a pressure sensor was attached to the right heel. Subjects drove a standard wheelchair using their right leg and trunk and pelvis ROM was measured in two separate sessions. To detect the trend of postural changes during propulsion, a trend curve was computed from the measured ROM using a low-pass filter and then subtracted from the measured ROM waveforms. The resulting curves were normalized and averaged, and the maximum, minimum, and amplitude of the cyclic variation during propulsion were assessed for reproducibility.

RESULTS

Intraclass correlation coefficients of the maximum, minimum, and amplitude ranged from 0.65 to 0.84.

CONCLUSIONS

The proposed method can estimate the posture change and the periodic fluctuation during wheelchair propulsion with high reproducibility.

Study protocol: multimodal physiotherapy as an add-on treatment to botulinum neurotoxin type A therapy for patients with cervical dystonia: DysPT-multi-a prospective, multicentre, single-blind, randomized, controlled study

Background

Botulinum neurotoxin (BoNT) is currently the best therapeutic option in the treatment for cervical dystonia (CD). Additional treatments like physiotherapy (PT) may even improve the results of the BoNT injection with type A (BoNT-A), but there are no definite recommendations. In the last few years, some studies showed tendencies for PT as an adjuvant therapy to benefit. However, high-quality studies are required.

Methods

This study is a multicentre, randomized, single-blind, controlled trial to demonstrate the effectiveness of a multimodal PT program compared to a nonspecific cupping therapy, additionally to the BoNT-A therapy. Two hundred participants will be assigned into the multimodal PT plus BoNT intervention arm or the BoNT plus cupping arm using randomization. Primary endpoint is the total Score of Toronto Western Spasmodic Rating Scale (TWSTRS). Secondary endpoints are the mobility of the cervical spine (range of motion, ROM), the TWSTRS subscales, and the quality of life (measured by questionnaires: CDQ-24 and SF-36). Patients will be single-blind assessed every 3 months according to their BoNT injection treatment over a period of 9 months.

Discussion

The study aims to determine the effectiveness and therefore potential benefit of an additional multimodal physiotherapy for standardized treatment with BoNT-A in patients with CD, towards the BoNT-therapy alone. This largest randomized controlled trial in this field to date is intended to generate missing evidence for therapy guidelines.

Trial registration

The study was registered in the German Clinical Study Register before the start of the patient recruitment (DRKS00020411; date: 21.01.2020).

Test - re-test reliability and concurrent validity of cervical active range of motion in young asymptomatic adults using a new inertial measurement unit device

OBJECTIVES

Cervical range of motion (CROM) is one of the first things evaluated in cervical disorders. DyCare-Lynx is an inertial measurement unit device that was recently designed to measure CROM. Therefore, the objectives of the present study were to test the reliability and validity of the DyCare-Lynx device for active CROM.

MATERIALS AND METHODS

This study included 36 healthy individuals for the reliability study and 31 individuals for the validity study. Test-retest reliability was examined in three different days, by the same examiner with a 4 ± 1-day interval between them in all cervical movements in random order. For validity, the CROM was tested with the Zebris Motion Analysis system and DyCare-Lynx simultaneously.

RESULTS

The interclass correlation coefficient (ICC) of the DyCare-Lynx ranged from 0.54 to 0.90. The standard error of measurement (SEM) ranged from 2.12°-7.65°. The smallest detectable change (SDD) ranged from 11.25% to 29.75%. The Pearson's r correlation of DyCare-Lynx with Zebris ranged from 0.655 to 0.957.

CONCLUSION

DyCare-Lynx showed moderate to excellent reliability and moderate-to-high validity. Moreover, SEM was low with acceptable SDD values for all movements. Overall, it can be suggested that DyCare-Lynx is a reliable and valid tool to evaluate active CROM.

Numerical Investigation of Spinal Cord Injury After Flexion-Distraction Injuries At the Cervical Spine

Flexion-distraction injuries frequently cause traumatic cervical spinal cord injury (SCI). Post-traumatic instability can cause aggravation of the secondary SCI during patient's care. However, there is little information on how the pattern of disco-ligamentous injury affects the SCI severity and mechanism. This study objective was to analyze how different flexion-distraction disco-ligamentous injuries affect the SCI mechanisms during post-traumatic flexion and extension. A cervical spine finite element model including the spinal cord was used and different combinations of partial or complete intervertebral disc (IVD) rupture and disruption of various posterior ligaments were modeled at C4-C5, C5-C6 or C6-C7. In flexion, complete IVD rupture combined with posterior ligamentous complex rupture was the most severe injury leading to the most extreme von Mises stress (47 to 66 kPa), principal strains p1 (0.32 to 0.41 in white matter) and p3 (-0.78 to -0.96 in white matter) in the spinal cord and to the most important spinal cord compression (35 to 48 %). The main post-trauma SCI mechanism was identified as compression of the anterior white matter at the injured level combined with distraction of the posterior spinal cord during flexion. There was also a concentration of the maximum stresses in the gray matter after injury. Finally, in extension, the injuries tested had little impact on the spinal cord. The capsular ligament was the most important structure in protecting the spinal cord. Its status should be carefully examined during patient's management.

Changes in Children's Body Composition and Posture during Puberty Growth

The main goal of our study was to determine how the age of children, puberty and anthropometric parameters affect the formation of body composition and faulty body posture development in children. The secondary goal was to determine in which body segments abnormalities most often occur and how gender differentiates the occurrence of adverse changes in children's body posture and body composition during puberty. The study group consisted of 464 schoolchildren aged from 6-16. Body posture was assessed with the Zebris system. The composition of the body mass was tested with Tanita MC 780 MA body mass analyzer and the body height was measured using a portable stadiometer PORTSTAND 210. The participants were further divided due to the age of puberty. Tanner division was adopted. The cut-off age for girls is ≥10 years and for boys it is ≥12 years. The analyses applied descriptive statistics, the Pearson correlation, stepwise regression analysis and the t-test. The accepted level of significance was p < 0.05. The pelvic obliquity was lower in older children (beta = -0.15). We also see that age played a significant role in the difference in the height of the right pelvis (beta = -0.28), and the difference in the height of the right shoulder (beta = 0.23). Regression analysis showed that the content of adipose tissue (FAT%) increased with body mass index (BMI) and decreased with increasing weight, age, and height. Moreover, the FAT% was lower in boys than in girls (beta negative equal to -0.39). It turned out that older children (puberty), had greater asymmetry in the right shoulder blade (p < 0.001) and right shoulder (p = 0.003). On the other hand, younger children (who were still before puberty) had greater anomalies in the left trunk inclination (p = 0.048) as well as in the pelvic obliquity (p = 0.008). Girls in puberty were characterized by greater asymmetry on the right side, including the shoulders (p = 0.001), the scapula (p = 0.001) and the pelvis (p < 0.001). In boys, the problem related only to the asymmetry of the shoulder blades (p < 0.001). Girls were characterized by a greater increase in adipose tissue and boys by muscle tissue. Significant differences also appeared in the body posture of the examined children. Greater asymmetry within scapulas and shoulders were seen in children during puberty. Therefore, a growing child should be closely monitored to protect them from the adverse consequences of poor posture or excessive accumulation of adipose tissue in the body.

Normative values of cervical range of motion for both children and adults: A systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

To synthesize studies reporting normative values of active cervical range of motion (ROM) in healthy children and adults.

SUMMARY OF BACKGROUND DATA

Evaluating active cervical ROM is part of routine assessment of patients with neck pain. Interpretation of outcomes necessitates having normative data per age category. Currently available normative values differ across studies, perhaps due to (the measurement properties of) the devices used.

METHODS

A systematic review according to PRISMA guidelines was conducted. Electronic searches included EMBASE, MEDLINE, Web of Science, Cochrane, CINAHL and Google Scholar databases from inception to August 2018. Included studies had to involve healthy subjects in which active cervical ROM was assessed or when determining normative values was the aim of the study. Methodological quality of the included studies was assessed using an adapted version of the QUADAS. A mean value was re-calculated for the total group in case data were presented per gender per age-category only. When possible, data were pooled.

RESULTS

From 2151 unique hits, 217 articles were selected for full text assessment, after which 162 articles were excluded. Data were extracted from 55 articles using 16 different measurement devices. Twenty-five studies were rated as being of "low risk of bias". Only data from studies evaluating the CROM device and Zebris could be pooled.

CONCLUSIONS

This systematic review revealed that although a large number of studies assessed normative data for active cervical ROM, the methodological quality of most studies was low and the heterogeneity between studies was high. Only the normative data for active cervical ROM using the CROM device seems to be useful. Overall, reference values for measuring active cervical ROM is unclear for most measurement devices. Normative values of cervical range of motion for both children and adults: a systematic review.

Concurrent validity and reliability of measuring range of motion during the cervical flexion rotation test with a novel digital goniometer

BACKGROUND

Headache is a common and costly health problem. Although the pathogenesis of headache is heterogeneous, reported contributing factors are dysfunctions of the upper cervical spine. The flexion rotation test (FRT) is a commonly used diagnostic test to detect upper cervical movement impairment. A digital goniometer may support precise measurement of movement impairment in the upper cervical spine. However, its reliability and validity is not assessed, yet. The aim of this study was to investigate the reliability and validity of the digital goniometer compared to an ultrasound-based movement analysis system.

METHODS

Two separate cross-sectional studies were conducted using the digital goniometer EasyAngle (Meloq AB, Stockholm, Sweden) for a) investigating the concurrent validity of upper cervical range of motion (ROM) during the FRT and b) determining the inter- and intra-rater reliability in the target population of patients with head and neck pain. Sixty-two participants, 39 with and 23 without head and neck pain, were recruited for the concurrent validity study. For the reliability study, a total of 50 participants were recruited. Intraclass correlation coefficients (ICC) and Bland Altmann plots were used to assess validity and ICC values, Bland Altmann plots as well as Kappa coefficients were used for estimating intra-rater and inter-rater reliability.

RESULTS

Concurrent validity was strong with an ICC (2,1) of 0.97 for ROM to either side (95%CI = 0.95-0.98). Bland Altman Plots revealed a mean difference between measurement systems of 0.5° for the left and 0.11° for the right side. The inter-rater ICC (2,1) was 0.66 (95%CI 0.47-0.79, p <  0.001, SEM 6.6°), indicating good reliability. The limits of agreement were between 10.25° and - 11.89°, the mean difference between both raters was - 0.82°. Intra-rater reliability for the measurement of ROM during the FRT was between 0.96 (ICC 3,1) for rater 1 and 0.94 (ICC 3,1) for rater 2.

CONCLUSIONS

The digital goniometer demonstrated strong concurrent validity and good to strong reliability and can be used in clinical practice to accurately determine movement impairment in the upper cervical spine.

TRIAL REGISTRATION

German Registry of Clinical Trials DRKS00013051 .

Comparison of spinal curvature parameters as determined by the ZEBRIS spine examination method and the Cobb method in children with scoliosis

BACKGROUND AND PURPOSE

The most common and gold standard method to diagnose and follow-up on scoliosis treatment is to capture biplanar X-ray images and then use these to determine the sagittal frontal spinal curvature angles by the Cobb method. Reducing exposure to radiation is an important aspect for consideration, especially regarding children. The ZEBRIS spinal examination method is an external, non-invasive measurement method that uses an ultrasound-based motion analysis system. The aim of this study is to compare angle values of patients with adolescent idiopathic scoliosis (AIS) determined by the ZEBRIS spine examination method with the angle values defined by the gold standard Cobb method on biplanar X-ray images.

METHODS

Subjects included 19 children with AIS (mean age 14.5±2.1 years, range 8-16 years, frontal plane thoracic Cobb angle 19.95±10.23°, thoracolumbar/lumbar angle 16.57±10.23°). The thoracic kyphosis and lumbar lordosis in the sagittal plane and the thoracic and lumbar scoliosis values were calculated by the Cobb method on biplanar X-ray images. The sagittal frontal spinal curvature angles were calculated from the position of the processus spinosus of 19 vertebrae, as determined by the ZEBRIS spine examination method. The validity of the ZEBRIS spine examination method was evaluated with Bland-Altman analyses between the sagittal and frontal spinal curvature parameters calculated from data determined by the ZEBRIS spine examination method and data obtained by the Cobb method on the X-ray images.

RESULTS AND DISCUSSION

Thoracic spinal curvature angles in sagittal and in frontal planes can be measured with sufficient accuracy. The slopes of the linear regression lines for thoracic kyphosis (TK) and thoracic scoliosis (TSC) are close to one (1.00 and 0.79 respectively), and the intercept values are below 5 degrees. The correlation between the TK and TSC values determined by the two methods is significant (p = 0.000) and excellent (rTK = 0.95, rTSC = 0.85). The differences are in the limit of agreement. The lumbar lordosis (LL) in the sagittal plane shows a very good correlation (rLL = 0.76); however the differences between the angles determined by the two methods are out of the limit of agreement in patients with major lumbar lordosis (LL≥50°). The thoracolumbar/lumbar spinal curvature angles in the frontal plane determined by ZEBRIS spine examination were underestimated at curvatures larger than 15°, mainly due to the rotational and pathological deformities of the scoliotic vertebrae. However, the correlation between lumbar scoliosis (LSC) values determined by the two methods is significant (p = 0.000) and excellent (rLSC = 0.84), the slopes are below one (0.71), the intercept values are below 5 degrees, and the differences between the angles determined by the two methods are within the limits of agreement. We could conclude that ZEBRIS spinal examination is a valid and reliable method for determination of sagittal and frontal curvatures during the treatment of patients with scoliosis. However, it cannot replace the biplanar X-ray examination for the visualization of spinal curvatures in the sagittal and frontal planes and the rotation of vertebral bodies during the diagnosis and annual evaluation of the progression.

Asymmetry of neck motion and activation of the cervical paraspinal muscles during prone neck extension in subjects with unilateral posterior neck pain

BACKGROUND

Although unilateral posterior neck pain (UPNP) is more prevalent than central neck pain, little is known about how UPNP affects neck motion and the muscle activation pattern during prone neck extension.

OBJECTIVE

To investigate whether deviation in neck motion and asymmetry of activation of the bilateral cervical paraspinal muscles occur during prone neck extension in subjects with UPNP compared to subjects without UPNP.

METHODS

This study recruited 20 subjects with UPNP and 20 age- and sex-matched control subjects without such pain. Neck motion and muscle onset time during prone neck extension were measured using a three-dimensional motion-analysis system and surface electromyography.

RESULTS

The deviation during prone neck extension was greater in the UPNP group than in the controls (p < 0.05). Compared with the controls, cervical extensor muscle activation in the UPNP group was significantly delayed on the painful side during prone neck extension (p < 0.05).

CONCLUSIONS

Subjects with UPNP showed greater asymmetry of neck motion and muscle activation during prone neck extension compared with the controls. This suggests that UPNP has specific effects on neck motion asymmetry and the functions of the cervical extensors, triggering a need for specific evaluation and exercises in the management of patients with UPNP.

Disturbed cervical proprioception affects perception of spatial orientation while in motion

The proprioceptive, visual and vestibular sensory systems interact to maintain dynamic stability during movement. The relative importance and interplay between these sensory systems is still not fully understood. Increased knowledge about spatial perception and postural orientation would provide better understanding of balance disorders, and their rehabilitation. Displacement of the body in space was recorded in 16 healthy subjects performing a sequence of stepping-in-place tests without any visual or auditory cues. Spatial displacement and orientation in space were determined by calculating two parameters, “Moved distance (sagittal + lateral displacement)” and “Rotation”. During the stepping-in-place tests vibration were applied in a randomized order on four different cervical muscles, and the effects were compared between muscles and to a non-vibration baseline condition. During the tests a forward displacement (“Moved distance”) was found to be the normal behavior, with various degrees of longitudinal rotation (“Rotation”). The moved distance was significantly larger when the vibration was applied on the dorsal muscles (916 mm) relative to on ventral muscles (715 mm) (p = 0.003) and the rate of displacement was significantly larger for dorsal muscles (36.5 mm/s) relative to ventral (28.7 mm/s) vs (p = 0.002). When vibration was applied on the left-sided muscles, 16° rotation to the right was induced (p = 0.005), whereas no significant rotation direction was induced with right-sided vibration (3°). The rate of rotation was significantly larger for vibration applied on ventral muscles (0.44°/s) relative to on dorsal (0.33°/s) (p = 0.019). The results highlight the influence of cervical proprioception on the internal spatial orientation, and subsequent for postural control.

A comparison of neck bending and flexion measurement methods for assessment of ergonomic risk

Head movements of workers were measured in the sagittal plane in order to establish a precise and accurate assessment method to be used in real work situations. Measurements were performed using two inclinometers connected to an embedded recording system. Two quantitative analysis methods were tested, i.e., measurement of bending with an inclinometer attached to the head, and measurement of flexion/extension by using an additional inclinometer located at C7/T1. The results were also compared with a video observation method (qualitative). The results showed that bending measurements were significantly different from those of flexion/extension for angles between 0° and 20°, and angles >45°. There were also significant differences between workers for flexion >45°, reflecting individual variability. Additionally, several limitations of observational methods were revealed by this study.

A slouched body posture decreases arm mobility and changes muscle recruitment in the neck and shoulder region

PURPOSE

Long-term use of unfavorable postures, congenital deformations and degenerative processes associated with aging or disease may generate an increased thoracic curvature resulting in pain and disability. We wanted to examine whether a slouched postural alignment with increased thoracic kyphosis changes the shoulder kinematics and muscle activity in upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) during arm elevation. The aim was to determine if a slouched posture influences range of motion, muscle activation patterns, maximal muscle activity and the total muscle work required when performing arm elevations.

METHOD

Twelve male subjects (23.3 ± 1.5 years) performed maximum arm elevations in upright and slouched postures. A combined 3D movement and EMG system recorded arm movements and spine curvature simultaneously with EMG activity in the UT, LT and SA.

RESULTS

Slouched posture affected the biomechanical conditions by significantly decreasing maximum arm elevation by ~15° (p < 0.001) and decreasing arm movement velocity by ~8 % during movements upwards (p < 0.001) and downwards (p = 0.034). The peak muscle activity increased in all muscles: UT (p = 0.034, +32.3 %), LT (p = 0.001, +48.6 %) and SA (p = 0.007, +20.9 %). The total muscle work increased significantly in the slouched posture during movements upwards: UT (p = 0.003, +36.6 %), LT (p < 0.001, +89.0 %), SA (p = 0.002, +19.4 %) and downwards: UT (p = 0.012, +29.8 %) and LT (p < 0.001, +122.5 %).

CONCLUSION

An increased thoracic kyphosis was found associated with marked increased physical costs when performing arm movements. Hence, patients suffering from neck-shoulder pain and disability should be investigated and treated for defective thoracic curvature issues.

Local Muscle Fatigue and 3D Kinematics of the Cervical Spine in Healthy Subjects

The authors aimed to further explore the effects of local muscle fatigue on cervical 3D kinematics and the interrelationship between these kinematic characteristics and local muscle endurance capacity in the unimpaired cervical spine. Twenty healthy subjects (38 ± 10 years; 5 women) performed 2 × 10 maximal cervical flexion-extension movements. Isometric muscle endurance tests (prone/supine lying) were applied between sets to induce local muscle fatigue quantified by Borg scale rates of perceived exertion (RPE) and slope in mean power frequency (MPF; surface electromyography; m. sternocleidomastoideus, m. splenius capitis). Cervical motion characteristics (maximal range of motion [ROM], coefficient of variation of the 10 repetitive movements, mean angular velocity, conjunct movements in transversal and frontal plane) were calculated from raw 3D ultrasonic movement data. Average isometric strength testing duration for flexion and extension correlated to the cervical ROM (r = .49/r = .48; p < .05). However, Student's t test demonstrated no significant alterations in any kinematic parameter following local muscle fatigue (p > .05). Although subjects' cervical muscle endurance capacity and motor output seems to be conjugated, no impact of local cervical muscle fatigue on motor function was shown. These findings underline the importance of complementary measures to address muscular performance and kinematic characteristics in outcome assessment and functional rehabilitation of the cervical spine.

Reliability and criterion validity of two applications of the iPhone™ to measure cervical range of motion in healthy participants

SUMMARY OF BACKGROUND DATA

Recent smartphones, such as the iPhone, are often equipped with an accelerometer and magnetometer, which, through software applications, can perform various inclinometric functions. Although these applications are intended for recreational use, they have the potential to measure and quantify range of motion. The purpose of this study was to estimate the intra and inter-rater reliability as well as the criterion validity of the clinometer and compass applications of the iPhone in the assessment cervical range of motion in healthy participants.

METHODS

The sample consisted of 28 healthy participants. Two examiners measured cervical range of motion of each participant twice using the iPhone (for the estimation of intra and inter-reliability) and once with the CROM (for the estimation of criterion validity). Estimates of reliability and validity were then established using the intraclass correlation coefficient (ICC).

RESULTS

We observed a moderate intra-rater reliability for each movement (ICC = 0.65-0.85) but a poor inter-rater reliability (ICC < 0.60). For the criterion validity, the ICCs are moderate (>0.50) to good (>0.65) for movements of flexion, extension, lateral flexions and right rotation, but poor (<0.50) for the movement left rotation.

CONCLUSION

We found good intra-rater reliability and lower inter-rater reliability. When compared to the gold standard, these applications showed moderate to good validity. However, before using the iPhone as an outcome measure in clinical settings, studies should be done on patients presenting with cervical problems.

Experimentally induced deep cervical muscle pain distorts head on trunk orientation

PURPOSE

We wanted to explore the specific proprioceptive effect of cervical pain on sensorimotor control. Sensorimotor control comprises proprioceptive feedback, central integration and subsequent muscular response. Pain might be one cause of previously reported disturbances in joint kinematics, head on trunk orientation and postural control. However, the causal relationship between the impact of cervical pain on proprioception and thus on sensorimotor control has to be established.

METHODS

Eleven healthy subjects were examined in their ability to reproduce two different head on trunk targets, neutral head position (NHP) and 30° target position, with a 3D motion analyser before, directly after and 15 min after experimentally induced neck pain. Pain was induced by hypertonic saline infusion at C2/3 level in the splenius capitis muscle on one side (referred to as "injected side").

RESULTS

All subjects experienced temporary pain and the head repositioning error increased significantly during head repositioning to the 30° target to the injected side (p = 0.011). A post hoc analysis showed that pain interfered with proprioception to the injected side during acute pain (p < 0.001), but also when the pain had waned (p = 0.002). Accuracy decreased immediately after pain induction for the 30° target position to the side where pain was induced (3.3 → 5.3°, p = 0.033), but not to the contralateral side (4.9 → 4.1°, p = 0.657). There was no significant impact of pain on accuracy for NHP. A sensory mismatch appeared in some subjects, who experienced dizziness.

CONCLUSIONS

Acute cervical pain distorts sensorimotor control with side-specific changes, but also has more complex effects that appear when pain has waned.

Test-retest reliability of 3D ultrasound measurements of the thoracic spine

OBJECTIVE

To explore the reliability of the Zebris CMS 20 ultrasound analysis system with pointer application for measuring end-range flexion, end-range extension, and neutral kyphosis angle of the thoracic spine.

SETTING

The study was performed within the School of Physiotherapy in cooperation with the Orthopedic Department at a University Hospital.

PARTICIPANTS

The thoracic spines of 28 healthy subjects were measured.

METHODS

Measurements for neutral kyphosis angle, end-range flexion, and end-range extension were taken once at each time point. The bone landmarks were palpated by one examiner and marked with a pointer containing 2 transmitters using a frequency of 40 kHz. A third transmitter was fixed to the pelvis, and 3 microphones were used as receiver. The real angle was calculated by the software. Bland-Altman plots with 95% limits of agreement, intraclass correlations (ICC), standard deviations of mean measurements, and standard error of measurements were used for statistical analyses. The test-retest reliability in this study was measured within a 24-hour interval.

MAIN OUTCOME MEASUREMENTS

Statistical parameters were used to judge reliability.

RESULTS

The mean kyphosis angle was 44.8° with a standard deviation of 17.3° at the first measurement and a mean of 45.8° with a standard deviation of 16.2° the following day. The ICC was high at 0.95 for the neutral kyphosis angle, and the Bland-Altman 95% limits of agreement were within clinical acceptable margins. The ICC was 0.71 for end-range flexion and 0.34 for end-range extension, whereas the Bland-Altman 95% limits of agreement were wider than with the static measurement of kyphosis. Compared with static measurements, the analysis of motion with 3-dimensional ultrasound showed an increased standard deviation for test-retest measurements.

CONCLUSIONS

The test-retest reliability of ultrasound measuring of the neutral kyphosis angle of the thoracic spine was demonstrated within 24 hours. Bland-Altman 95% limits of agreement and the standard deviation of differences did not appear to be clinically acceptable for measuring flexion and extension.

Do inertial sensors represent a viable method to reliably measure cervical spine range of motion?

A rise in neck pain cases has initiated an exponential interest in the assessment and treatment of cervical spine range of motion (CROM). Experimental limitations, however, have been reported as therapists strive to collect continuous, dynamic data to aid prognosis. This technical report seeks to explore the viability of using inertial sensors to reliably assess CROM. In recognition of the need for secure skin-sensor attachment, four combinations of sensor pairings were established and investigated based upon four clinically identifiable surface landmarks. Twelve participants were recruited and asked to perform three specific movement cycles in each plane (i.e. flexion-extension; rotation; lateral bending). The reliability of the peak CROM, and the movement pattern, recorded in each of the three movement cycles was statistically analysed using the intra-class correlation coefficient (ICC) and coefficient of multiple correlations (CMC). It was determined that the most reliable positions of the orientation sensors, with one adhered to the forehead and the other representing T4, enables data to be recorded with a reliability that is comparable to other CROM measuring techniques. Subsequently, it is concluded that inertial sensors represent a viable method to assess CROM.

Axial and torsional stability of supracondylar femur osteotomies: biomechanical comparison of the stability of five different plate and osteotomy configurations

PURPOSE

Little is known regarding the biomechanical stability and stiffness of implants and techniques used in supracondylar femur osteotomies (SCO). Therefore, fixation stability and stiffness of implants to bone was investigated under simulated physiological loading conditions using a composite femur model and a 3D motion-analysis system.

METHODS

Five osteotomy configurations were investigated: (1) oblique medial closing-wedge fixated with an angle-stable implant; (2) oblique and (3) perpendicular medial closing-wedge, both fixated with an angled blade plate; and lateral opening-wedge fixated with (4) a spacer plate and (5) an angle-stable lateral implant. The motion measured at the osteotomy was used to calculate the stiffness and stability of the constructs.

RESULTS

The least amount of motion and highest stiffness was measured in the medial oblique closing-wedge osteotomy fixated with the angled blade plate. The lateral opening-wedge techniques were less stable and had a lower stiffness compared with the medial; the oblique saw cuts were more stable and had a higher stiffness than the perpendicular.

CONCLUSION

This experimental study presents baseline data on the differences in the primary stability of bone-implant constructs used in SCO. The data in this study can be used as reference for future testing of SCO techniques. Furthermore, it is recommended that based on the differences found, the early postoperative rehabilitation protocol is tailored to the stability and stiffness of the fixation method used.

Influence of number of operated levels and postoperative time on active range of motion following anterior cervical decompression and fusion procedures

STUDY DESIGN

A cohort study analyzing the cervical range of motion of subjects with anterior cervical decompression and fusion operation (ACDF).

OBJECTIVE

The purpose of this study was to compare the cervical range of motion of subjects who underwent an ACDF operation to age-matched healthy nonoperative subjects. Subjects were divided according to the number of operated levels, postoperative time point, and level of disability.

SUMMARY OF BACKGROUND DATA

ACDF is an operative treatment aimed at expansion of the spinal canal and relief of cord compression. In addition to alleviating pain, 2 common tools are used to measure postoperative success; cervical range of motion kinematic analysis and subjective evaluation questionnaires (Neck Disability Index [NDI]).

METHODS

This study involved 25 preoperative and 110 postoperative ACDF subjects as well as 18 control volunteers with no prior history of neck complaints. ACDF subjects were divided according to the number of operated levels; 1-, 2-, 3-, and 4-levels as well as time of their clinical visit; preoperative, early, and late postoperative. Before kinematic testing, the subjects were asked to complete the NDI survey. A virtual reality assisted electromagnetic tracking was used to measure an active voluntary motion of the head relative to the torso. The subjects' maximum range of motion was calculated and compared as they executed 3 to 5 consecutive cycles of the primary motions, flexion/extension, axial rotation, and lateral bending. An analysis of variance statistical test (P < 0.01) was used to determine significant differences between study groups. RESULTS.: Subject's range of motion decreased relative to control as the number of operated levels increased. Moreover, 1- and 2-level subjects increased their range motion relative to preoperative. Finally, there was a decrease in range of motion as the subject's level of disability increased as measured by an NDI score but all subjects reported a lower score relative to preoperative time point.

CONCLUSION

The active range of motion of subjects who underwent an ACDF surgery increased postoperative and was dependent on the number of operated levels. In addition, there was an improvement in the disability level after the surgery as measured by the NDI score.

In vivo intersegmental motion of the cervical spine using an inverse kinematics procedure

BACKGROUND

The main functions of the cervical spine are the stabilization and the orientation of the head. Pathologies are complex and difficult to diagnose. The first sign of the dysfunction is an abnormal intervertebral motion. It is the purpose of this feasibility study to determine the intersegmental motions and loading conditions of the cervical spine in vivo with standard clinical investigation methods.

METHODS

We propose a new approach which merges full flexion-extension X-ray images, and continuous motion of the whole cervical spine obtained with a tracking motion system. These data were used as input for a subject-specific rigid body model of the cervical spine computed with the software MSC.Adams. This model simulates the cervical spine extension/flexion, the intervertebral motions are deduced using an inverse kinematics procedure.

FINDINGS

Subject-specific rigid body models were computed from data of two subjects. The intersegmental motion and loading conditions were calculated. We found that the loading amplitudes depended on the intervertebral level, and that subject specific patterns were highlighted. We noticed an unsymmetrical behavior in flexion and extension. Furthermore intervertebral rotations were correlated with the global motion of the cervical spine.

INTERPRETATION

A subject-specific rigid body model merged data from classical flexion-extension radiographs and noninvasive external motion capture. Our approach is based on inverse kinematics allowing the estimation of the intervertebral motion and mechanical behavior of the cervical spine in vivo, which gives valuable information concerning biomechanics of the cervical spine in vivo for cervical spine clinical investigation.

Neck pain assessment in a virtual environment

STUDY DESIGN

Neck-pain and control group comparative analysis of conventional and virtual reality (VR)-based assessment of cervical range of motion (CROM).

OBJECTIVES

To use a tracker-based VR system to compare CROM of individuals suffering from chronic neck pain with CROM of asymptomatic individuals; to compare VR system results with those obtained during conventional assessment; to present the diagnostic value of CROM measures obtained by both assessments; and to demonstrate the effect of a single VR session on CROM.

SUMMARY OF BACKGROUND DATA

Neck pain is a common musculoskeletal complaint with a reported annual prevalence of 30% to 50%. In the absence of a gold standard for CROM assessment, a variety of assessment devices and methodologies exist. Common to these methodologies, assessment of CROM is carried out by instructing subjects to move their head as far as possible. However, these elicited movements do not necessarily replicate functional movements which occur spontaneously in response to multiple stimuli. To achieve a more functional approach to cervical motion assessment, we have recently developed a VR environment in which electromagnetic tracking is used to monitor cervical motion while participants are involved in a simple yet engaging gaming scenario.

METHODS

CROM measures were collected from 25 symptomatic and 42 asymptomatic individuals using VR and conventional assessments. Analysis of variance was used to determine differences between groups and assessment methods. Logistic regression analysis, using a single predictor, compared the diagnostic ability of both methods.

RESULTS

Results obtained by both methods demonstrated significant CROM limitations in the symptomatic group. The VR measures showed greater CROM and sensitivity while conventional measures showed greater specificity. A single session exposure to VR resulted in a significant increase in CROM.

CONCLUSION

Neck pain is significantly associated with reduced CROM as demonstrated by both VR and conventional assessment methods. The VR method provides assessment of functional CROM and can be used for CROM enhancement. Assessment by VR has greater sensitivity than conventional assessment and can be used for the detection of true symptomatic individuals.

Influence of prolonged unilateral cervical muscle contraction on head repositioning--decreased overshoot after a 5-min static muscle contraction task

The ability to reproduce a specified head-on-trunk position can be an indirect test of cervical proprioception. This ability is affected in subjects with neck pain, but it is unclear whether and how much pain or continuous muscle contraction factors contribute to this effect. We studied the influence of a static unilateral neck muscle contraction task (5 min of lateral flexion at 30% of maximal voluntary contraction) on head repositioning ability in 20 subjects (10 women, 10 men; mean age 37 years) with healthy necks. Head repositioning ability was tested in the horizontal plane with 30 degrees target and neutral head position tests; head position was recorded by Zebris((R)), an ultrasound-based motion analyser. Head repositioning ability was analysed for accuracy (mean of signed differences between introduced and reproduced positions) and precision (standard deviation of the differences). Accuracy of head repositioning ability increased significantly after the muscle contraction task, as the normal overshoot was reduced. An average overshoot of 7.1 degrees decreased to 4.6 degrees after the muscle contraction task for the 30 degrees target and from 2.2 degrees to 1.4 degrees for neutral head position. The increased accuracy was most pronounced for movements directed towards the activated side. Hence, prolonged unilateral neck muscle contraction may increase the sensitivity of cervical proprioceptors.

Three-dimensional analysis of the cervical spine kinematics: effect of age and gender in healthy subjects

STUDY DESIGN.: A three-dimensional (3D) analysis of the cervical spine kinematics in vivo about a large asymptomatic database in order to evaluate the impact of age and gender on the neck's performances. OBJECTIVE.: To investigate the effect of age and gender on kinematical parameters of the cervical spine, specifically quantitative parameters concerning coupled movements and proprioception, using the infra-red POLARIS measurement system. SUMMARY OF BACKGROUND DATA.: Cervical spine kinematics has been investigated in vivo by numerous authors using various devices. However, few is known about the influence of gender and age on the 3D cervical biomechanics, specifically regarding coupled movements and proprioceptive abilities. METHODS.: A total of 140 asymptomatic volunteers (70 men and 70 women) aged 20 to 93 years old were enrolled. The noninvasive infrared system Polaris was used to quantify the 3D range of motion (ROM) of cervical spine and to evaluate proprioceptive abilities. For validating the protocol in terms of reproducibility, 12 volunteers were tested 3 times by 2 independent operators. RESULTS.: The standard error of measurement for the maximal ROM in the 3 space planes was 5%. Gender had no significant influence on the 3D cervical ROM, except for the "70-79 years old" group. Age had a significant influence on all main movements showing 0.55 degrees to 0.79 degrees magnitude decrease per decade. Age and gender had no significant influence on coupled movements. "Head-to-Target" proprioception was significantly affected by the age only in the horizontal plane. CONCLUSION.: A data base for cervical ROM, pattern of motion, and proprioceptive capability was established in population of 140 healthy subjects of various age and gender. Significant age-related decrease in ROM and proprioceptive abilities were observed in this study. Coupled movements did not vary with gender or age; however, their role in the cervical performance increased with age since main movements were limited.

The assessment of the cervical spine. Part 1: Range of motion and proprioception

Neck pain and headache of cervical origin are complaints affecting an increasing number of the general population. Mechanical factors such as sustained neck postures or movements and long-term "abnormal" physiologic loads on the neck are believed to affect the cervical structures and compromise neck function. A comprehensive assessment of neck function requires evaluation of its physical parameters such as range of motion, proprioception, strength and endurance/fatigue. The complicated structure of the cervical spine however, makes it difficult for any clinician to obtain reliable and valid results. The aim of the first part of this systematic critical review is to identify the factors influencing the assessment of range of motion and proprioception of the cervical spine.

Cervical proprioception is sufficient for head orientation after bilateral vestibular loss

The aim was to investigate the relative importance of cervical proprioception compared to vestibular input for head movements on trunk. Subjects with bilateral vestibulopathy (n = 11) were compared to healthy controls (n = 15). We studied their ability to move the head accurately to reproduce four specified target positions in the horizontal yaw plane (neutral head position, 10 degrees target, 30 degrees target, and 30 degrees target with oscillating movements applied during target introduction). Repositioning ability was calculated as accuracy (constant error, the mean of signed differences between introduced and reproduced target) and precision (variable error, the standard deviation of differences between introduced and reproduced targets). Subjects with bilateral vestibulopathy did not differ significantly from controls in their ability to reproduce different target positions. When the 30 degrees target position was introduced with oscillating movements, overshoot diminished and accuracy improved in both groups, although only statistically significantly when performed towards the right side. The results suggest that at least in some conditions, accurate head on trunk orientation can be achieved without vestibular information and that cervical somato-sensory input is either up-regulated as a compensatory mechanism after bilateral vestibular loss or is important for such tasks.

Cervical motion assessment using virtual reality

STUDY DESIGN

Repeated measures of cervical motion in asymptomatic subjects.

OBJECTIVES

To introduce a virtual reality (VR)-based assessment of cervical range of motion (ROM); to establish inter and intratester reliability of the VR-based assessment in comparison with conventional assessment in asymptomatic individuals; and to evaluate the effect of a single VR session on cervical ROM.

SUMMARY OF BACKGROUND DATA

Cervical ROM and clinical issues related to neck pain is frequently studied. A wide variety of methods is available for evaluation of cervical motion. To date, most methods rely on voluntary responses to an assessor's instructions. However, in day-to-day life, head movement is generally an involuntary response to multiple stimuli. Therefore, there is a need for a more functional assessment method, using sensory stimuli to elicit spontaneous neck motion. VR attributes may provide a methodology for achieving this goal.

METHODS

A novel method was developed for cervical motion assessment utilizing an electromagnetic tracking system and a VR game scenario displayed via a head mounted device. Thirty asymptomatic participants were assessed by both conventional and VR-based methods. Inter and intratester repeatability analyses were performed. The effect of a single VR session on ROM was evaluated.

RESULTS

Both assessments showed non-biased results between tests and between testers (P > 0.1). Full-cycle repeatability coefficients ranged between 15.0 degrees and 29.2 degrees with smaller values for rotation and for the VR assessment. A single VR session significantly increased ROM, with largest effect found in the rotation direction.

CONCLUSION

Inter and intratester reliability was supported for both the VR-based and the conventional methods. Results suggest better repeatability for the VR method, with rotation being more precise than flexion/extension. A single VR session was found to be effective in increasing cervical motion, possibly due to its motivating effect.

The effects of the Mulligan Sustained Natural Apophyseal Glide (SNAG) mobilisation in the lumbar flexion range of asymptomatic subjects as measured by the Zebris CMS20 3-D motion analysis system

Background

Mulligan's mobilisation techniques are thought to increase the range of movement (ROM) in patients with low back pain. The primary aim of this study was to investigate the application of the Mulligan's Sustained Natural Apophyseal Glide (SNAG) technique on lumbar flexion ROM. The secondary aim was to measure the intra- and inter-day reliability of lumbar ROM employing the same procedure.

Methods

49 asymptomatic volunteers participated in this double-blinded study. Subjects were randomly assigned to receive either SNAG mobilisation (n = 25), or a sham mobilisation (n = 24). The SNAG technique was applied at the L₃and L₄ spinal levels with active flexion in sitting by an experienced manual therapist. Three sets of 10 repetitions at each of the two spinal levels were performed. The sham mobilisation was similar to the SNAG but did not apply the appropriate direction or force. Lumbar ROM was measured by a three dimensional electronic goniometer (Zebris CMS20), before and after each technique. For the reliability, five measurements in two different days (one week apart) were performed in 20 healthy subjects.

Results

When both interventions were compared, independent t tests yielded no statistically significant results in ROM between groups (p = 0.673). Furthermore no significant within group differences were observed: SNAG (p = 0.842), sham (p = 0.169). Intra- and inter-day reliability of flexion measurements was high (ICC_1,1 > 0.82, SEM < 4.0°, SDD<16.3%) indicating acceptable clinical applicability.

Conclusion

While the Zebris proved to be a reliable device for measuring lumbar flexion ROM, SNAG mobilisation did not demonstrate significant differences in flexion ROM when compared to sham mobilisation.

Trial registration

Current Controlled Trials NCT00678093.

Clinimetric evaluation of active range of motion measures in patients with non-specific neck pain: a systematic review

The study is to provide a critical analysis of the research literature on clinimetric properties of instruments that can be used in daily practice to measure active cervical range of motion (ACROM) in patients with non-specific neck pain. A computerized literature search was performed in Medline, Cinahl and Embase from 1982 to January 2007. Two reviewers independently assessed the clinimetric properties of identified instruments using a criteria list. The search identified a total of 33 studies, investigating three different types of measurement instruments to determine ACROM. These instruments were: (1) different types of goniometers/inclinometers, (2) visual estimation, and (3) tape measurements. Intra- and inter-observer reliability was demonstrated for the cervical range of motion instrument (CROM), Cybex electronic digital instrument (EDI-320) and a single inclinometer. The presence of agreement was assessed for the EDI-320 and a single inclinometer. The CROM received a positive rating for construct validity. When clinical acceptability is taken into account both the CROM and the single inclinometer can be considered appropriate instruments for measuring the active range of motion in patients with non-specific neck pain in daily practice. Reliability is the aspect most frequently evaluated. Agreement, validity and responsiveness are documented less frequently.

Quantification of the coupled motion that occurs with axial rotation and lateral bending of the head-neck complex: an experimental examination

The vertebrae of the cervical spine exhibit out-of-plane or coupled motion during axial rotation and lateral bending. Quantifying the range of motion (ROM) of this occurrence can aid the understanding of cervical spine injury mechanisms and disorders, as well as the development of new treatment methods. Previous studies have formulated ratios to describe coupled motion obtained from in-vitro examinations. The aim of the present study was to use in-vivo test data to develop mathematical relationships to quantify the coupled motion that occurs with axial rotation and lateral bending of the head-neck complex. Using a three-dimensional motion analyser it was possible to trace the coupling effect throughout the full range of unrestricted head-neck motion. Values for primary and coupled ROMs were obtained, showing no significant difference between male and female primary ROMs but a small disparity between male and female coupled ROMs. Regression equations were found to quantify coupled motion throughout the range of axial rotation and lateral bending. The present experimental study also examines the range of horizontally fixed axial rotation of the head to determine the minimum amount of coupled lateral bending that takes place, which has not been measured previously.

Acute neck pain: Cervical spine range of motion and position sense prior to and after joint mobilization

Despite the relatively high prevalence of cervical spine pain, the efficacy of treatment procedures is limited. In the current study, range of motion and proprioception was assessed prior to and after specific cervical spine mobilisation techniques. A 44-year-old male office worker presented with a history of cervical pain of 1 day duration. He had woken with pain, stiffness and a loss of range of motion. Examination findings indicated pain to be at C5-6 on the left side. Measurement of maximal three-dimensional cervical motion was undertaken using a Zebris system. A position matching task tested the individual's ability to actively reposition their head and neck. The treatment undertaken involved grade III down-slope mobilisations on the left side at C5-6 and C6-7 in supine lying. This technique was then progressed by placing the subject in an upright sitting position, and sustained natural apophyseal glides were performed at C6. Immediately following the treatment, the patient reported a considerable decrease in pain, less difficulty in movement and reduced stiffness. Motion analyses showed the most marked percentage improvements in range of motion after treatment were in flexion (55%), extension (35%), left rotation (56%), and left lateral flexion (22%). Ipsilateral lateral flexion with axial rotation was also notably improved following treatment. No change in proprioceptive ability was found following the treatment. The findings showed that the application of standardised specific mobilisation techniques led to substantial improvements in the range of motion and the restitution of normal coupled motion.

Comparison of cervical spine kinematics using a fluoroscopic model for adjacent segment degeneration

Object

In this cervical spine kinematics study the authors evaluate the motions and forces in the normal, degenerative, and fused states to assess how alteration in the cervical motion segment affects adjacent segment degeneration and spondylosis.

Methods

Fluoroscopic images obtained in 30 individuals (10 in each group with disease at C5–6) undergoing flexion/extension motions were collected. Kinematic data were obtained from the fluoroscopic images and analyzed with an inverse dynamic mathematical model of the cervical spine that was developed for this analysis.

Results

During 20° flexion to 15° extension, average relative angles at the adjacent levels of C6–7 and C4–5 in the fused patients were 13.4° and 8.8° versus 3.7° and 4.8° in the healthy individuals. Differences at C3–4 averaged only about 1°. Maximum transverse forces in the fused spines were two times the skull weight at C6–7 and one times the skull weight at C4–5, compared with 0.2 times the skull weight and 0.3 times the skull weight in the healthy individuals. Vertical forces ranged from 1.6 to 2.6 times the skull weight at C6–7 and from 1.2 to 2.5 times the skull weight at C4–5 in the patients who had undergone fusion, and from 1.4 to 3.1 times the skull weight and from 0.9 to 3.3 times the skull weight, respectively, in the volunteers.

Conclusions

Adjacent-segment degeneration may occur in patients with fusion due to increased motions and forces at both adjacent levels when compared with healthy individuals in a comparable flexion and extension range.

Reliability and Normative Database of the Zebris Cervical Range-of-Motion System in Healthy Controls with Preliminary Validation in a Group of Patients with Neck Pain

OBJECTIVE

The first aim of this study was to determine the reliability of the Zebris (Achen, Germany) ultrasound-based testing of cervical range of motion (ROM). The second aim was to develop a normative database in a healthy sample of 96 volunteers. The third aim was to evaluate, with the Zebris system, the ROM in a sample of patients with chronic neck pain compared to healthy controls to determine if cervical ROM could discriminate between these groups and between subgroups of pain patients (with or without whiplash injury).

METHODS

The study participants were 96 healthy volunteers, 14 patients with idiopathic neck pain, and 16 patients with chronic whiplash. Cervical ROM was measured in the 3 planes with the Zebris CMS 70P ultrasound-based motion analysis system. The intra- and interrater reliability of the protocol was tested in 12 volunteers.

RESULTS

Full-cycle measurements showed high reliability (intraclass correlation coefficient, 0.80-0.94) with the SE of measurement ranging from 4.25 degrees to 7.88 degrees. The distribution of ROM measures showed a great individual variation, with a significant age-related decrease in ROM in all directions. Range of motion was reduced in patients with chronic whiplash in all primary movements, compared to healthy subjects, whereas in patients with idiopathic neck pain, only rotation showed reduced ROM.

CONCLUSION

Results demonstrate a high degree of test-retest reliability in measuring cervical ROM. The use of normative data for ROM when evaluating patients with neck disorders needs to take age into account. The current study has demonstrated that patients with chronic neck pain demonstrate reduced ROM, which differs between patients with idiopathic neck pain and those with chronic whiplash.

Association between cervicocephalic kinesthetic sensibility and frequency of subclinical neck pain

Although impaired neck proprioception has been demonstrated in patients with chronic neck pain, previous studies have not consistently shown any association between pain intensity and proprioceptive performance. We therefore investigated whether temporal aspects of pain are associated with cervicocephalic kinesthetic sensibility. One hundred and twenty-seven adults with or without subclinical neck pain undertook two tasks, repositioning their heads to the neutral head position (head-to-NHP) and target position (head-to-target) in sagittal and transverse plane. Absolute error was calculated from position data recorded by an ultrasound-based motion analysis system. Pain frequency, duration, and intensity were evaluated using a questionnaire. A mixed effects model was constructed to test the effect on reposition error by different pain factors, with age, gender and maximal cervical range of motion as covariates. A higher pain frequency was associated with greater reposition errors for all movement directions in the head-to-NHP task. No consistent effect was observed for pain intensity or duration. In the case of the head-to-target task, no consistent effect was observed for any of the three pain factors. The findings reveal that pain frequency, not the intensity or duration of pain, is associated with neck proprioception in individuals with subclinical neck pain.

Three-dimensional motion analysis of the lumbar spine during "free squat" weight lift training

BACKGROUND

Heavy weight lifting using a squat bar is a commonly used athletic training exercise. Previous in vivo motion studies have concentrated on lifting of everyday objects and not on the vastly increased loads that athletes subject themselves to when performing this exercise.

HYPOTHESIS

Athletes significantly alter their lumbar spinal motion when performing squat lifting at heavy weights.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-eight athletes (28 men, 20 women) performed 6 lifts at 40% maximum, 4 lifts at 60% maximum, and 2 lifts at 80% maximum. The Zebris 3D motion analysis system was used to measure lumbar spine motion. Exercise was performed as a "free" squat and repeated with a weight lifting support belt. Data obtained were analyzed using SAS.

RESULTS

A significant decrease (P < .05) was seen in flexion in all groups studied when lifting at 40% maximum compared with lifting at 60% and 80% of maximum lift. Flexion from calibrated 0 point ranged from 24.7 degrees (40% group) to 6.8 degrees (80% group). A significant increase (P < .05) was seen in extension when lifting at 40% maximum was compared with lifting at 60% and 80% maximum lift. Extension from calibrated 0 point ranged from -1.5 degrees (40% group) to -20.3 degrees (80% group). No statistically significant difference was found between motion seen when exercise was performed as a free squat or when lifting using a support belt in any of the groups studied.

CONCLUSION

Weight lifting using a squat bar causes athletes to significantly hyperextend their lumbar spines at heavier weights. The use of a weight lifting support belt does not significantly alter spinal motion during lifting.

Cervical range of motion and cephalic kinesthesis: ultrasonographic analysis by age and sex

STUDY DESIGN

Exploratory experimental design.

OBJECTIVE

To assess cervical range of motion (ROM) and ability to return the head to a neutral position in healthy subjects according to age and sex.

SUMMARY OF BACKGROUND DATA

Cervical ROM and ability to return the head to a neutral position have been studied, but no data on the influence of age and sex in this movement is available.

METHODS

We divided 232 healthy volunteers able to sit for 20 minutes into 6 age groups: 15-24, 25-34, 35-44, 45-54, 55-65, and older than 65 years. Zebris 3-dimensional ultrasonography measured the active cervical ROM and ability to return the head to the neutral position. Bone landmarks and vertical position were defined for each subject. Recorded data were neutral position, lateral bending (right and left), flexion-extension, and axial rotation (right and left). We evaluated patients' ability, without external intervention, to return the head to a self-defined neutral position.

RESULTS

ROM was affected by age as assessed by analysis of variance (F = 27.8 in the sagittal plane, F = 12.1 in the frontal plane, and F = 19.7 in the axial plane; all P < 0.0001), but neither sex nor age affected ability to return the head to a neutral position (F = 0.615, P = 0.688 on the left; F = 0.808, P = 0.545 on the right). Maximal ROM was observed for right axial rotation.

CONCLUSIONS

We provide a database by age and sex for patient ability to return the head to the neutral position and for cervical ROM. This database could be used as a reference in clinical applications.

Movement behaviour in patients with chronic neck pain

BACKGROUND AND PURPOSE

The present study evaluated whether patients with chronic neck pain demonstrate characteristic angular movement deviations during repeated cervical spine movements.

METHOD

Sixteen patients with chronic neck pain and a group of 18 aged-matched healthy control subjects performed 10 repetitive maximal cervical movement cycles (flexion/extension, rotation, lateral flexion) at a self-determined velocity. To collect the kinematic data of the cervical spine, a three-dimensional ultrasonic movement analysis system (Zebris CMS70, Germany) was used. To describe the movement variability in the maximum oscillation amplitudies the intra-subject coefficients of variation (CV %) was calculated. The maximum difference was characterized by the absolute differences between the minimum and maximum oscillation amplitudes of iterated movement cycles. Pain intensity was obtained by visual analogue scales (VAS).

RESULTS

The average pain rating of the patients with chronic neck pain indicated moderate neck pain intensity (3.7 (+/-0.8)). Independent Student's t-tests revealed a significantly decreased range of movement (ROM) in the chronic neck pain group for all anatomic values (p < 0.05), except for the lateral flexion to the right. The maximum differences and variability parameters showed significantly increased values in the chronic neck pain group in all directions (p < 0.001).

CONCLUSION

Maximal cervical ROM was significantly lower, and movement variability was significantly higher, in patients compared with healthy control subjects. The differences of cervical motion variability point towards increased movement irregularities in patients with chronic neck pain. The present study shows evidence to support the hypothesis that additional information may be gained from the analysis of movement variability.

Reliability of the spin-T cervical goniometer in measuring cervical range of motion in an asymptomatic Indian population

OBJECTIVE

To examine the intratester reliability of the Spin-T goniometer, a cervical range of motion device, in a normal Indian population.

METHODS

Subjects comprised 30 healthy adults with mean age of 34 years (range, 18-65 years). The subjects were stabilized in the sitting position and the Spin-T goniometer mounted on the head of the subject. The study design was a within-subject repeated intratester reliability trial conducted for cervical range of motion in 6 directions of movement. Three measurements were taken in each direction (flexion, extension lateral flexion, and lateral rotation) per participant. Reliability coefficients, intraclass correlation coefficients, and 95% confidence interval were derived from repeated-measures analysis of variance (ANOVA). Where differences in ANOVA were detected, a paired t test was conducted and the typical error values and coefficient of variance were calculated.

RESULTS

All repeated measures showed high intraclass correlation coefficients (all >0.96, P < .01). The ANOVA detected no differences between trials for all movements except rotation. The typical error values for the rotation trials did not exceed 2.5 degrees and the coefficient of variance did not exceed 4%, which is clinically acceptable considering the normally variable cervical range of movement.

CONCLUSION

In this study, the Spin-T goniometer proved to be a reliable measuring instrument for cervical range of movement in an Indian population. The use of a laser pointer fixed to the instrument ensured a consistent neutral start position.

Validation of the spin-T goniometer, a cervical range of motion device

OBJECTIVE

To test the validity of the Spin-T goniometer for the assessment of cervical range of movement.

METHODS

A linear regression analysis for paired neck movements using first a foam head model and then human subjects was performed to quantify the differences between the measurements obtained from the MotionStar, a movement-tracking device, and the Spin-T. A within-subject repeated measures design using simultaneous data acquisition was completed.

RESULTS

The coefficient of determination (R2) for all planes of cervical range of motion for both model and human data sets was higher than 0.99. The regression equations for the model data showed no significant (P > .05) intercept for flexion-extension and lateral rotation. Human data showed statistically significant intercept for flexion-extension (mean, -0.52 degrees) and lateral flexion (mean, 0.81 degrees) at P < .05.

CONCLUSION

This study quantifies the difference between the MotionStar and the Spin-T goniometer and documents the systematic error between the measures. Where the error reached statistical significance, the magnitude of the error was very small (< 1.5 degrees). The results of this study suggest that the Spin-T goniometer may be used as a valid measuring instrument for cervical range of movement.