Adolescent standing postural response to backpack loads: a randomised controlled experimental study

BACKGROUND: Backpack loads produce changes in standing posture when compared with unloaded posture. Although 'poor' unloaded standing posture has been related to spinal pain, there is little evidence of whether, and how much, exposure to posterior load produces injurious effects on spinal tissue. The objective of this study was to describe the effect on adolescent sagittal plane standing posture of different loads and positions of a common design of school backpack. The underlying study aim was to test the appropriateness of two adult 'rules-of-thumb'-that for postural efficiency, backpacks should be worn high on the spine, and loads should be limited to 10% of body weight. METHOD: A randomised controlled experimental study was conducted on 250 adolescents (12–18 years), randomly selected from five South Australian metropolitan high schools. Sagittal view anatomical points were marked on head, neck, shoulder, hip, thigh, knee and ankle. There were nine experimental conditions: combinations of backpack loads (3, 5 or 10% of body weight) and positions (backpack centred at T7, T12 or L3). Sagittal plane photographs were taken of unloaded standing posture (baseline), and standing posture under the experimental conditions. Posture was quantified from the x (horizontal) coordinate of each anatomical point under each experimental condition. Differences in postural response were described, and differences between conditions were determined using Analysis of Variance models. RESULTS: Neither age nor gender was a significant factor when comparing postural response to backpack loads or conditions. Backpacks positioned at T7 produced the largest forward (horizontal) displacement at all the anatomical points. The horizontal position of all anatomical points increased linearly with load. CONCLUSION: There is evidence refuting the 'rule-of-thumb' to carry the backpack high on the back. Typical school backpacks should be positioned with the centre at waist or hip level. There is no evidence for the 10% body weight limit

The postural effects of load carriage on young people – a systematic review

BACKGROUND: Spinal pain in young people is a significant source of morbidity in industrialised countries. The carriage of posterior loads by young people has been linked with spinal pain, and the amount of postural change produced by load carriage has been used as a measure of the potential to cause tissue damage. The purpose of this review was to identify, appraise and collate the research evidence regarding load-carriage related postural changes in young people. METHODS: A systematic literature review sought published literature on the postural effects of load carriage in young people. Sixteen databases were searched, which covered the domains of allied health, childcare, engineering, health, health-research, health-science, medicine and medical sciences. Two independent reviewers graded the papers according to Lloyd-Smith's hierarchy of evidence scale. Papers graded between 1a (meta-analysis of randomised controlled trials) and 2b (well-designed quasi-experimental study) were eligible for inclusion in this review. These papers were quality appraised using a modified Crombie tool. The results informed the collation of research evidence from the papers sourced. RESULTS: Seven papers were identified for inclusion in this review. Methodological differences limited our ability to collate evidence. CONCLUSIONS: Evidence based recommendations for load carriage in young people could not be made based on the results of this systematic review, therefore constraining the use of published literature to inform good load carriage practice for young people

Responsiveness and minimal clinically important difference for pain and disability instruments in low back pain patients

BACKGROUND: The choice of an evaluative instrument has been hampered by the lack of head-to-head comparisons of responsiveness and the minimal clinically important difference (MCID) in subpopulations of low back pain (LBP). The objective of this study was to concurrently compare responsiveness and MCID for commonly used pain scales and functional instruments in four subpopulations of LBP patients. METHODS: The Danish versions of the Oswestry Disability Index (ODI), the 23-item Roland Morris Disability Questionnaire (RMQ), the physical function and bodily pain subscales of the SF36, the Low Back Pain Rating Scale (LBPRS) and a numerical rating scale for pain (0–10) were completed by 191 patients from the primary and secondary sectors of the Danish health care system. Clinical change was estimated using a 7-point transition question and a numeric rating scale for importance. Responsiveness was operationalised using standardardised response mean (SRM), area under the receiver operating characteristic curve (ROC), and cut-point analysis. Subpopulation analyses were carried out on primary and secondary sector patients with LBP only or leg pain +/- LBP. RESULTS: RMQ was the most responsive instrument in primary and secondary sector patients with LBP only (SRM = 0.5–1.4; ROC = 0.75–0.94) whereas ODI and RMQ showed almost similar responsiveness in primary and secondary sector patients with leg pain (ODI: SRM = 0.4–0.9; ROC = 0.76–0.89; RMQ: SRM = 0.3–0.9; ROC = 0.72–0.88). In improved patients, the RMQ was more responsive in primary and secondary sector patients and LBP only patients (SRM = 1.3–1.7) while the RMQ and ODI were equally responsive in leg pain patients (SRM = 1.3 and 1.2 respectively). All pain measures demonstrated almost equal responsiveness. The MCID increased with increasing baseline score in primary sector and LBP only patients but was only marginally affected by patient entry point and pain location. The MCID of the percentage change score remained constant for the ODI (51%) and RMQ (38%) specifically and differed in the subpopulations. CONCLUSION: RMQ is suitable for measuring change in LBP only patients and both ODI and RMQ are suitable for leg pain patients irrespectively of patient entry point. The MCID is baseline score dependent but only in certain subpopulations. Relative change measured using the ODI and RMQ was not affected by baseline score when patients quantified an important improvement

Prevalence of sleep disturbance in patients with low back pain

Low back pain (LBP) is a common health condition that is often associated with disability, psychological distress and work loss. Worldwide, billions of dollars are expended each year trying to manage LBP, often with limited success. Recently, some researchers have reported that LBP patients also report sleep disturbance as a result of their LBP. However, as most of this evidence was obtained from highly selected groups of patients or from studies with small samples, high quality data on prevalence of sleep disturbance for patients with LBP are lacking. It is also unclear whether sleep disturbance is more likely to be reported by patients with recent-onset LBP than by patients with persistent LBP. Finally, it is not known whether high pain intensity, the most relevant condition-specific variable, is associated with higher rates of reported sleep disturbance. The present study aimed to determine the prevalence of reported sleep disturbance in patients with LBP. In addition, we aimed to determine whether sleep disturbance was associated with the duration of back pain symptoms and whether pain intensity was associated with reported sleep disturbance. Data from 1,941 patients obtained from 13 studies conducted by the authors or their colleagues between 2001 and 2009 were used to determine the prevalence of sleep disturbance. Logistic regression analyses explored associations between sleep disturbance, the duration of low back symptoms and pain intensity. The estimated prevalence of sleep disturbance was 58.7% (95% CI 56.4–60.7%). Sleep disturbance was found to be dependent on pain intensity, where each increase by one point on a ten-point visual analogue scale (VAS) was associated with a 10% increase in the likelihood of reporting sleep disturbance. Our findings indicate that sleep disturbance is common in patients with LBP. In addition, we found that the intensity of back pain was only weakly associated with sleep disturbance, suggesting that other factors contribute to sleep problems for LBP patients