Comparison of the posture of school children carrying backpacks versus pulling them on trolleys.
Schmidt J., Docherty S.
Objective: To investigate whether there is a difference in the posture of school children walking with a backpack versus pulling a trolley.
Design: Comparative, controlled, pilot trial. Subjects: Thirty-four school children between 6 and 8 years of age. Methods: Initially, neutral posture was measured in a standing position. All children were then asked to walk a predetermined route without intervention for approximately 7 min. This was followed by walking the same route with either a backpack (n = 19) or trolley (n = 15). Deviations from neutral of the thoracic and lumbar spine (flexion, extension, lateral flexion and rotation) from the final 30 s of the imaging sequences were taken and analysed.
Results: Compared to unburdened walking, walking with a backpack led to a statistically significant (p ≤ 0.05) increase in thoracic extension (3.91°, 95% CI = 3.35–4.46) and right lumbar lateral flexion (2.29°, 95% CI = −3.41 to −1.18), and a statistically significant decrease of lumbar flexion (2.2°, 95% CI = 0.34–4.06). In contrast, walking with a trolley increased extension (1.4°, 95% CI = 0.72–2.08), right lateral flexion (1.24°, 95% CI = −1.91 to −0.57) and right rotation (3.09°, 95% CI = −3.85 to −2.32) of the thoracic spine, and led to a statistically significant increase in left rotation (3.57°, 95% CI = 2.58–4.55) of the lumbar spine. Comparing the backpack and trolley groups showed a statistically significant (p ≤ 0.05) increase in thoracic extension and right lumbar lateral flexion in the backpack group. Posture during trolley pulling was characterized by a statistically significant (p ≤ 0.05) increase in right thoracic and left lumbar rotation.
Conclusion: Participants adopted asymmetric postures during walking with a backpack and pulling a trolley. However, the trolley group was characterised by spinal rotation which possibly adds an extra source of stress. This suggests that school children should use backpacks rather than trolleys when the weight is within recommended limits.
Gait & Posture 2010, 32(4):436-445.
The test-retest reliability of centre of pressure measures in bipedal static task conditions- a systematic review of the literature.
Ruhe A, Fejer R, Walker B.
Summary of Background Data: The analysis of centre of pressure (COP) excursions is used as an index of postural stability in standing. Conflicting data have been reported over the past 20 years regarding the reliability of COP measures and no standard procedure for COP measure use in study design has been established.
Search Methods: Six online databases (January 1980 to February 2009) were systematically searched followed by a manual search of retrieved papers.
Results: Thirty-two papers met the inclusion criteria. The majority of the papers (26/32, 81.3%) demonstrated acceptable reliability. While COP mean velocity (mVel) demonstrated variable but generally good reliability throughout the different studies (r=0.32-0.94), no single measurement of COP appeared significantly more reliable than the others. Regarding data acquisition duration, a minimum of 90 sec is required to reach acceptable reliability for most COP parameters. This review further suggests that while eyes closed readings may show slightly higher reliability coefficients, both eyes open and closed setups allow acceptable readings under the described conditions (r≥0.75). Also averaging the results of three to five repetitions on firm surface is necessary to obtain acceptable reliability. A sampling frequency of 100 Hz with a cut-off frequency of 10 Hz is also recommended. No final conclusion regarding the feet position could be reached.
Conclusions: The studies reviewed show that bipedal static COP measures may be used as a reliable tool for investigating general postural stability and balance performance under specific conditions. Recommendations for maximizing the reliability of COP data are provided.
European Spine Journal 2010 Aug 19.
Center of pressure excursion as a measure of balance performance in patients with non-specific low back pain compared to healthy controls.
Ruhe A, Fejer R, Walker B.
Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While many studies investigated COP excursions in low back pain patients and healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists. Six online databases were systematically searched followed by a manual search of the retrieved papers. The selection criteria comprised papers comparing COP measures derived from bipedal static task conditions on a force-plate of non-specific low back pain (NSLBP) sufferers to those of healthy controls. Sixteen papers met the inclusion criteria. Heterogeneity in study designs prevented pooling of the data so only a qualitative data analysis was conducted. The majority of the papers (14/16, 88%) concluded that NSLBP patients have increased COP mean velocity and overall excursion as compared to healthy individuals. This was statistically significant in the majority of studies (11/14, 79%). An increased sway in antero-posterior direction was also observed in NSLBP patients. Patients with NSLBP exhibit greater postural instability than healthy controls, signified by greater COP excursions and a higher mean velocity. While the decreased postural stability in NSLBP sufferers further appears to be associated with the presence of pain, it seems unrelated to the exact location and pain duration. No correlation between the pain intensity and the magnitude of COP excursions could be identified.
BMC Musculoscelet Disord. 2011 Jul 15;12:162.
Is there a relationship between pain intensity and postural sway in patients with non-specific low back pain?
Ruhe A, Fejer R, Walker B.
Background: Increased center of pressure excursions are well documented in patients suffering from non-specific low back pain, whereby the altered postural sway includes both higher mean sway velocities and larger sway area. No investigation has been conducted to evaluate a relationship between pain intensity and postural sway in adults (aged 50 or less) with non-specific low back pain.
Methodes: Seventy-seven patients with non-specific low back pain and a matching number of healthy controls were enrolled. Center of pressure parameters were measured by three static bipedal standing tasks of 90 sec duration with eyes closed in narrow stance on a firm surface. The perceived pain intensity was assessed by a numeric rating scale (NRS-11), an equal number of patients (n = 11) was enrolled per pain score.
Results: Generally, our results confirmed increased postural instability in pain sufferers compared to healthy controls. In addition, regression analysis revealed a significant and linear increase in postural sway with higher pain ratings for all included COP parameters. Statistically significant changes in mean sway velocity in antero-posterior and medio-lateral direction and sway area were reached with an incremental change in NRS scores of two to three points.
Conclusion: COP mean velocity and sway area are closely related to self-reported pain scores. This relationship may be of clinical use as an objective monitoring tool for patients under treatment or rehabilitation.
Chiropr Man Therap. 2011 May 24;19(1):13.
Altered postural sway in patients suffering from non-specific neck pain and whiplash associated disorder - A systematic review of the literature.
Ruhe A, Fejer R, Walker B.
Study Design: Systematic literature review.
Objectives: To assess differences in center of pressure (COP) measures in patients suffering from non-specific neck pain (NSNP) or whiplash-associated disorder (WAD) compared to healthy controls and any relationship between changes in postural sway and the presence of pain, its intensity, previous pain duration and the perceived level of disability.
Summary of Background Data: Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While several studies investigated COP excursions in neck pain and WAD patients and compared these to healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists.
Search Methodes: Six online databases were systematically searched followed by a manual search of the retrieved papers.
Selection Criteria: Papers comparing COP measures derived from bipedal static task conditions on a force plate of people with NSNP and WAD to those of healthy controls.
Data Collection and Analysis: Two reviewers independently screened titles and abstracts for relevance. Screening for final inclusion, data extraction and quality assessment were carried out with a third reviewer to reconcile differences.
Results: Ten papers met the inclusion criteria. Heterogeneity in study designs prevented pooling of the data and no direct comparison of data across the studies was possible. Instead, a qualitative data analysis was conducted. There was broad consensus that patients with either type of neck pain have increased COP excursions compared to healthy individuals, a difference that was more pronounced in people with WAD. An increased sway in antero-posterior direction was observed in both groups.
Conclusion: Patients with neck pain (due to either NSNP or WAD) exhibit greater postural instability than healthy controls, signified by greater COP excursions irrespective of the COP parameter chosen. Further, the decreased postural stability in people with neck pain appears to be associated with the presence of pain and correlates with the extent of proprioceptive impairment, but appears unrelated to pain duration.