Sharon M.H. Tsang

Normal kinematics of the neck: The interplay between the cervical and thoracic spines

The movement coordination between the cervical and thoracic spine was examined in 34 asymptomatic participants (24 female and 10 male). Three-dimensional electromagnetic motion sensors were attached to the skin overlying the head, T1, T6, and T12 spinous processes to measure the angular displacement of the cervical, upper thoracic, and lower thoracic spine during active neck movements. These displacement measurements were found to have excellent reliability, with intraclass correlation coefficient ranging from 0.899 to 0.993. The angular displacement-time curves of the cervical and upper thoracic spine were also highly repeatable, with coefficient of multiple determinations ranging from 0.900 to 0.967. Both the cervical and thoracic spines were found to contribute to active neck motion, the greatest contribution being from the cervical region in all movement directions. The inter-regional movement coordination between the cervical spine and upper thoracic spine in all three planes of movement was found to be high, as determined by cross-correlation analysis of the movements of the regions. The current results suggest that the motion of the thoracic spine, in particular the upper thoracic spine, contributes to neck mobility, and that the upper thoracic spine should be included during clinical examination of neck dysfunction.

Altered spinal kinematics and muscle recruitment pattern of the cervical and thoracic spine in people with chronic neck pain during functional task

Knowledge on the spinal kinematics and muscle activation of the cervical and thoracic spine during functional task would add to our understanding of the performance and interplay of these spinal regions during dynamic condition. The purpose of this study was to examine the influence of chronic neck pain on the three-dimensional kinematics and muscle recruitment pattern of the cervical and thoracic spine during an overhead reaching task involving a light weight transfer by the upper limb. Synchronized measurements of the three-dimensional spinal kinematics and electromyographic activities of cervical and thoracic spine were acquired in thirty individuals with chronic neck pain and thirty age- and gender-matched asymptomatic controls. Neck pain group showed a significantly decreased cervical velocity and acceleration while performing the task. They also displayed with a predominantly prolonged coactivation of cervical and thoracic muscles throughout the task cycle. The current findings highlighted the importance to examine differential kinematic variables of the spine which are associated with changes in the muscle recruitment in people with chronic neck pain. The results also provide an insight to the appropriate clinical intervention to promote the recovery of the functional disability commonly reported in patients with neck pain disorders.

Movement coordination and differential kinematics of the cervical and thoracic spines in people with chronic neck pain.

BACKGROUND Research on the kinematics and inter-regional coordination of movements between the cervical and thoracic spines in motion adds to our understanding of the performance and interplay of these spinal regions. The purpose of this study was to examine the effects of chronic neck pain on the three-dimensional kinematics and coordination of the cervical and thoracic spines during active movements of the neck. METHODS Three-dimensional spinal kinematics and movement coordination between the cervical, upper thoracic, and lower thoracic spines were examined by electromagnetic motion sensors in thirty-four individuals with chronic neck pain and thirty-four age- and gender-matched asymptomatic subjects. All subjects performed a set of free active neck movements in three anatomical planes in sitting position and at their own pace. Spinal kinematic variables (angular displacement, velocity, and acceleration) of the three defined regions, and movement coordination between regions were determined and compared between the two groups. FINDINGS Subjects with chronic neck pain exhibited significantly decreased cervical angular velocity and acceleration of neck movement. Cross-correlation analysis revealed consistently lower degrees of coordination between the cervical and upper thoracic spines in the neck pain group. The loss of coordination was most apparent in angular velocity and acceleration of the spine. INTERPRETATION Assessment of the range of motion of the neck is not sufficient to reveal movement dysfunctions in chronic neck pain subjects. Evaluation of angular velocity and acceleration and movement coordination should be included to help develop clinical intervention strategies to promote restoration of differential kinematics and movement coordination.

Postural Drainage or Flutter® Device in Conjunction with Breathing and Coughing Compared to Breathing and Coughing Alone in Improving Secretion Removal and Lung Function in Patients with Acute Exacerbation of Bronchiectasis: A Pilot Study

Abstract Maximizing normal coughing, the single best means for clearing pulmonary secretions and protecting the lung, is a primary focus of physiotherapy in patients with impaired mucociliary clearance. In busy Hong Kong hospitals, patients are often encouraged to use breathing and coughing (BC) manoeuvres, in conjunction with other techniques such as postural drainage (PD) and the use of the Flutter(r) device (FL), as self-treatment to mobilize secretions. This pilot study examined whether the effects of PD and FL on secretion clearance and lung function indices in patients with acute exacerbations of bronchiectasis were greater than that of BC alone. Fifteen patients admitted with bronchiectasis were randomly allocated to three groups: PD+BC, FL+BC and BC alone. Treatment was applied for 15 minutes daily in all groups, until the day of discharge. Variables measured included wet weight sputum production (during the 15-minute treatment time, during the subsequent 15-minute post-treatment period, and over 24 hours), forced vital capacity, forced expiratory volume in 1 second, and peak expiratory flow rate. Variables were recorded on Days 2 and 4 after admission and on the day of discharge. Patients were asked to allocate subjective ease and effectiveness scores for their treatment method. There was no difference in sputum production or lung function parameters among the three groups at any of the measurement points. Patients reported that all techniques were equally easy to use, but FL was perceived as being the most effective in clearing secretions. PD and FL do not appear to facilitate secretion removal beyond that achieved by BC alone.

The effects of bending speed on the lumbo-pelvic kinematics and movement pattern during forward bending in people with and without low back pain

BackgroundImpaired lumbo-pelvic movement in people with low back pain during bending task has been reported previously. However, the regional mobility and the pattern of the lumbo-pelvic movement were found to vary across studies. The inconsistency of the findings may partly be related to variations in the speed at which the task was executed. This study examined the effects of bending speeds on the kinematics and the coordination lumbo-pelvic movement during forward bending, and to compare the performance of individuals with and without low back pain.MethodsThe angular displacement, velocity and acceleration of the lumbo-pelvic movement during the repeated forward bending executed at five selected speeds were acquired using the three dimensional motion tracking system in seventeen males with low back pain and eighteen males who were asymptomatic. The regional kinematics and the degree of coordination of the lumbo-pelvic movement during bending was compared and analysed between two groups.ResultsSignificantly compromised performance in velocity and acceleration of the lumbar spine and hip joint during bending task at various speed levels was shown in back pain group (p < 0.01). Both groups displayed a high degree of coordination of the lumbo-pelvic displacement during forward bending executed across the five levels of speed examined. Significant between-group difference was revealed in the coordination of the lumbo-pelvic velocity and acceleration (p < 0.01). Asymptomatic group moved with a progressively higher degree of lumbo-pelvic coordination for velocity and acceleration while the back pain group adopted a uniform lumbo-pelvic pattern across all the speed levels examined.ConclusionsThe present findings show that bending speed imposes different levels of demand on the kinematics and pattern of the lumbo-pelvic movement. The ability to regulate the lumbo-pelvic movement pattern during the bending task that executed at various speed levels was shown only in pain-free individuals but not in those with low back pain. Individuals with low back pain moved with a stereotyped strategy at their lumbar spine and hip joints. This specific aberrant lumbo-pelvic movement pattern may have a crucial role in the maintenance of the chronicity in back pain.

Relationship between neck acceleration and muscle activation in people with chronic neck pain: Implications for functional disability

BACKGROUND Previous study has found that people with chronic neck pain moved with a consistently compromised acceleration/deceleration at their cervical and thoracic spines. This study examined the strength of the association between the electromyographic activities and the acceleration/deceleration of the cervical and thoracic spine, and its correlation with the functional disabilities in individuals with neck pain. METHODS Time history of the cervical and thoracic acceleration/deceleration and EMG activity was acquired in thirty-four subjects with chronic neck pain and thirty-four age- and gender-matched asymptomatic subjects during active neck movements. The strength of the association between the electromyographic activity of spinal muscles and the cervical and thoracic acceleration/deceleration was determined using cross-correlation method. Relationship between the strength of this association and the severity of the functional disabilities in neck pain group was examined using correlation analysis. FINDINGS The strength of the association between cervical and thoracic acceleration/deceleration and electromyographic activities was significantly lower in neck pain group. Significant negative correlations were found between the functional disability level and the strength of this defined association in the symptomatic group. INTERPRETATION The compromised capability of the spinal muscles to produce acceleration/deceleration in the neck pain group may imply an impaired electromechanical coupling of these spinal muscles when performing neck movements. Significant negative correlation of the degree of functional disabilities suggests that the present approach can be used as an objective and specific evaluation of the dynamic performance of the spinal muscles and its relationship with the functional disabilities in neck pain subjects.

Abdominal muscle recruitment and its effect on the activity level of the hip and posterior thigh muscles during therapeutic exercises of the hip joint

Abdominal exercise has been advocated to improve the protection of the spine and neuromuscular efficiency of the limb movements. The purpose of this study was to examine the effect of enhanced contraction of internal oblique and transversus abdominis (IO/TrA) on the activity level of the hip and posterior thigh muscles during therapeutic hip exercises. Twenty healthy females were required to perform eight hip exercises under two conditions, natural versus enhanced IO/TrA contraction conditions. Muscle activity of gluteus maximus, gluteus medius, tensor fasciae latae and biceps femoris of the exercising leg was measured by surface electromyography during hip exercises, and expressed in percentage normalized to the maximal voluntary isometric contraction (%MVIC). The activity levels of the gluteal and posterior thigh muscles recorded under natural and enhanced IO/TrA conditions were compared. IO/TrA was found to have activated at the range of 2.7%-16.1% and 6.3%-24.1% of MVIC when hip exercises were executed under natural and enhanced conditions respectively. Enhanced IO/TrA contraction resulted in significantly greater activity in gluteus maximus, gluteus medius and bicep femoris at various phases of hip extension and clam exercises, single leg sit-to-stand and pelvic drop exercise (increased by 1.7-7.2% of MVIC). These findings indicate the presence of coactivation of the abdominal and hip muscles when performing the free active hip exercises. Further studies are recommended to investigate the efficacy of this muscle coactivation in improving the clinical outcome of therapeutic hip exercises.

Changes in Lumbopelvic Movement and Muscle Recruitment Associated with Prolonged Deep Squatting: A Pilot Study

This study examined the changes in spinal kinematics and muscle recruitment of the lumbopelvic region associated with prolonged squatting. Eight subjects with chronic nonspecific low back pain (LBP) and eight asymptomatic subjects (AS) performed squat-to-stand and reverse movements, before and immediately after 15 min deep-squatting. Within-group and between-group differences in lumbopelvic kinematics and electromyographic activity acquired in lumbar erector spinae (ES), gluteus maximus (GM), and vastus lateralis (VL) were analyzed. During squat-to-stand after squatting, the LBP group showed slower then faster lumbar movement in the second and third quartiles, respectively. In the second quartile, the AS group moved with a significantly greater lumbar angle. However, significantly greater bilateral GM activity (+4–4.5%) was found in the LBP group only. A more profound decrease in bilateral ES activity (−10%) was also shown in the LBP group, yet this was nonsignificant compared to the AS group (−4%). In the third quartile, only the LBP group moved with a significantly greater lumbar angle, together with a significant increase in bilateral ES (+6–8%) and GM muscle (+2–3%) activity. The findings of the altered pattern of joint kinematics and recruitment of the key lumbopelvic muscles displayed in the LBP group inform on the possible mechanisms that may contribute to the increased risk of developing lumbar dysfunctions for people who work in prolonged squatting postures.

Association of electromyographic activation patterns with pain and functional disability in people with chronic neck pain

PurposeThis study examined the activation patterns of the cervical and thoracic muscles in people with and without chronic neck pain during functional activities and their associations with pain intensity and functional disability.MethodsThirty-four adults with chronic neck pain and 34 asymptomatic adults were recruited. They were requested to perform active cervical movements and an upper limb lifting task. Electromyographic activation patterns (EMG) of bilateral upper trapezius, cervical erector spinae, sternocleidomastoid, and thoracic erector spinae were recorded during these tasks. Correlation and multiple regression analysis were used to examine the associations between EMG variables and severity of pain and functional disability.ResultsWhen performing the cervical movements, the neck pain group displayed lower EMG activity levels, especially in the cervical and thoracic extensors. In addition, significantly prolonged activation was observed in seven of the ten muscles during the upper limb lifting task. The changes in EMG amplitude and activation duration were found to be significantly correlated with severity of pain (R2 = 0.716) and functional disability (R2 = 0.623).ConclusionsSignificant differences in the activation patterns of multiple cervical and thoracic muscles were found in individuals with neck pain compared with those without neck pain. These were significantly associated with their degree of pain and functional limitation. The findings of this study highlight the importance of assessing and optimising the neuromuscular activation of these muscles in the rehabilitation of those suffering from chronic neck pain.

Biomechanics of the Cervical Region During Use of a Tablet Computer

This study aimed to investigate the spinal muscle activity and postural variations across time in healthy young adults during a prolonged reading comprehension task using a tablet computer. Twenty healthy college students (10 males and 10 females; mean age = 21.5 ± 1.7 years) participated in this study. Subjects were seated on a standard office chair with adjustable height and allowed to move freely in their body postures during the 30-minute reading comprehension task. The subject was instructed to hold a Samsung Galaxy Tab S2 9.7 (SM-T810) with both hands. Surface electromyography and spinal kinematics were recorded simultaneously. The amplitude probability distribution function (APDF) was computed for each 10 min trial of the muscle activity data and postural angle data respectively. Amplitude measures of muscle activity using 50th%APDF and APDF range (difference between 90th% and 10th% APDF) were examined in 3 time phases (T1, T2, T3) of 10 min each. Postural variation (using zero crossing algorithm) was also analyzed. There was a significant increase in median muscle activity (50th%APDF) of bilateral cervical erector spinae (CES) (left: p = .002; right: p = .002) and a decreasing trend in bilateral thoracic erector spinae (TES) (left: p = .053; right: p = .068) over time. Significant increase of cervical postural variation was also revealed across time (p = 0.001). Finally, sex differences regardless of time effect were shown, with females showing significantly higher left CES median muscle activity (p = 0.044) and muscle activity range (p = 0.047) when compared with males. Other muscles did not reveal such significant differences.