Active sitting with backrest support: Is it feasible?

Ergonomics science recommends office chairs that promote active sitting to reduce sitting related complaints. Since current office chairs do not fulfill this recommendation, a new chair was developed by inverting an existing dynamic chair principle. This study compares active sitting on the inverted chair during a simulated computer-based office task to two existing dynamic office chairs (n = 8). Upper body stability was analysed using Friedman ANOVA (p = .01). In addition, participants completed a questionnaire to rate their comfort and activity after half a working day. The inverted chair allowed the participants to perform a substantial range of lateral spine flexion (11.5°) with the most stable upper body posture (≤11 mm, ≤2°, p ≤ .01). The results of this study suggest that the inverted chair supports active sitting with backrest support during computer-based office work. However, according to comfort and activity ratings, results should be verified in a future field study with 24 participants. Practitioner Summary: This experimental laboratory study analyses the feasibility of active sitting with a backrest support during common office work on a new type of dynamic office chair. The results demonstrate that active sitting with a backrest support is feasible on the new but limited on existing chairs.

What is the effect of sensory discrimination training on chronic low back pain? A systematic review.

BACKGROUND: Sensory discrimination training (SDT) for people with chronic low back pain (CLBP) is a novel approach based on theories of the cortical reorganization of the neural system. SDT aims to reverse cortical reorganization, which is observed in chronic pain patients. SDT is still a developing therapeutic approach and its effects have not been systematically reviewed. The aim of this systematic review was to evaluate if SDT decreases pain and improves function in people with CLBP. METHODS: A systematic review was performed on the available literature to evaluate the effects of SDT. Randomised controlled trials compared the effectiveness of SDT on pain and function in people with CLBP with the effectiveness of other physiotherapy interventions, no treatment, or sham therapy. The methodological quality of the included studies and the clinical relevance of reported treatment effects were investigated. RESULTS: The original search revealed 42 records of which 6 fulfilled the inclusion criteria. The majority of studies showed that SDT caused statistically significant improvements in pain and function, but only two studies reported clinically relevant improvements. The applied SDT varied considerably with regard to dosage and content. The methodological quality of the included studies also varied, which hampered the comparability of results. CONCLUSIONS: Although SDT seems to improve pain and function in people with CLBP, study limitations render firm conclusions unsafe. Future studies should pay closer attention to power and sample selection as well as to the content and dosage of the SDT intervention. We recommend a large, well-powered, prospective randomized control study that uses a standardized SDT approach to address the hypothesis that SDT causes clinically relevant improvements in pain and function.

The effect of visual feedback on people suffering from chronic back and neck pain - a systematic review.

Objectives: Visual feedback as an intervention for people suffering from chronic back or chronic neck pain is a novel approach based on the person's perception of the painful body part. Visual feedback is an innovative therapeutic approach whose effects have not yet been systematically reviewed specifically for people with chronic back or chronic neck pain. Therefore, a systematic review was performed on the literature to evaluate the effects of visual feedback on pain intensity in people with chronic back or neck pain. Methods: This systematic review investigated the magnitude and clinical relevance of the reported effects, as well as the reporting quality of the included studies. Pain intensity was defined as the outcome of interest to judge the clinical relevance of the findings. The quality of reporting and the risk of bias were assessed. Results: The original search revealed 359 studies of which five were included following screening of the title and abstract, application of the inclusion/exclusion criteria and reading the full texts. All five studies had investigated chronic back pain. Most studies showed either a momentary decrease of pain intensity during the application of a visual feedback method or a habitual decrease after treatment for 2 weeks. Discussion: While visual feedback does appear to alter pain intensity in people with chronic back pain, there is limited evidence from these studies to support visual feedback as an adjunct to therapy. These issues point out that future studies may be indicated.

Is active sitting on a dynamic office chair controlled by the trunk muscles?

Today's office chairs are not known to promote active sitting or to activate the lumbar trunk muscles, both of which functions are ergonomically recommended. This study investigated a newly developed dynamic office chair with a moveable seat, specifically designed to promote trunk muscle controlled active sitting. The study aimed to determine the means by which the seat movement was controlled during active sitting. This was accomplished by quantifying trunk and thigh muscular activity and body kinematics. Additionally, the effect of increased spinal motion on muscular activity and body kinematics was analysed. Ten subjects were equipped with reflective body markers and surface electromyography on three lumbar back muscles (multifidus, iliocostalis, longissimus) and two thigh muscles (vastus lateralis and medialis). Subjects performed a reading task during static and active sitting in spontaneous and maximum ranges of motion in a simulated office laboratory setting. The temporal muscle activation pattern, average muscle activity and body segment kinematics were analysed and compared using Friedman and post-hoc Wilcoxon tests (p≤0.05). Active sitting on the new chair significantly affected the lumbar trunk muscles, with characteristic cyclic unloading/loading in response to the seat movement. Neither thigh muscle activity nor lateral body weight shift were substantially affected by active sitting. When participants increased their range of motion, the lumbar back muscles were activated for longer and relaxation times were shorter. The characteristic activity pattern of the lumbar trunk muscles was shown to be the most likely dominant factor in controlling seat movement during active sitting. Consequently, the new chair may have a potential positive impact on back health during prolonged sitting. Further studies are necessary to analyse the frequency and intensity of active sitting during daily office work.

Validity and variability of center of pressure measures to quantify trunk control in stroke patients during quiet sitting and reaching tasks.

BACKGROUND: In the immediate period following stroke, sitting balance is one of the most important predictors of functional recovery at discharge after rehabilitation. Thus, sitting balance determines the content of the early phase of stroke rehabilitation and an appropriate measurement tool is important. RESEARCH QUESTION: The aim of this study is to investigate the concurrent validity of center of pressure (CoP) excursions of patients seated on a force plate, as well as to examine the daily variability of trunk control after stroke. METHODS: Twenty stroke patients at an inpatient rehabilitation clinic underwent two assessment sessions, on average eight hours apart. Each session comprised two trials: quiet sitting for 30 s; extended reaching in forward, backward, left and right directions. The Trunk Impairment Scale (TIS) was measured during the first session. CoP excursions were measured to determine the outcomes of sway area and sway velocity during stable sitting and the maximal excursions in frontal and sagittal planes during the reaching tasks. RESULTS: High Spearman's correlations (0.72, 0.79) were found between the TIS and the frontal and sagittal excursions. However, only low correlations between the TIS and the sway area and sway velocity were observed. Within sessions, all CoP outcomes showed high ICCs (0.73-1.00). Between sessions, high ICCs (0.86-0.93) were found except for sway velocity (ICC 0.51). Sway velocity increased significantly between sessions. SIGNIFICANCE: Frontal and sagittal CoP excursions during reaching tasks appear to be valid measurement parameters to evaluate trunk control in patients after stroke. Only small variability was observed and no significant differences between consecutive days.

Effectiveness of movement control exercise on patients with non-specific low back pain and movement control impairment: A systematic review and meta-analysis.

BACKGROUND: Patients with low back pain (LBP) and movement control impairment (MVCI) show altered spinal movement patterns. Treatment that aims to change movement behaviour could benefit these patients. OBJECTIVE: To assess the effectiveness of movement control exercise (MVCE) in terms of clinically relevant measures (disability and pain) on patients with NSLBP. METHODS: A systematic review and meta-analysis were conducted. CINAHL, MEDLINE, PUBMED and PEDro databases were searched for RCT's evaluating MVCE treatment in patients with NSLBP from review inception to April 2017. Authors were contacted to obtain missing data and outcomes. PEDro was used to assess methodological quality of the studies and the GRADE approach was used to assess the overall quality of evidence Data were combined using a random effects meta-analysis and reported as standardized mean differences (SMD). RESULTS: Eleven eligible RCT's including a total of 781 patients were found. Results show 'very low to moderate quality' evidence of a positive effect of MVCE on disability, both at the end of treatment and after 12 months (SMD -0.38 95%CI -0.68, -0.09 respectively 0.37 95%CI -0.61,-0.04). Pain intensity was significantly reduced after MVCE at the end of treatment (SMD -0.39 95%CI -0.69, -0.04), but not after 12 months (SMD -0.27, 95%CI -0.62, 0.09). CONCLUSIONS: MVCE intervention for people with NSLBP and MVCI appears to be more effective in improving disability compared to other interventions, both over the short and long term. Pain was reduced only in the short term. An important factor is the initial identification of patients with MVCI. Registration of the study: The study protocol registration number is CRD42016036662 on PROSPERO.

Reproducibility of a new signal processing technique to assess joint sway during standing.

Postural control strategies can be investigated by kinematic analysis of joint movements. However, current research is focussing mainly on the analysis of centre of pressure excursion and lacks consensus on how to assess joint movement during postural control tasks. This study introduces a new signal processing technique to comprehensively quantify joint sway during standing and evaluates its reproducibility. Fifteen patients with non-specific low back pain and ten asymptomatic participants performed three repetitions of a 60-second standing task on foam surface. This procedure was repeated on a second day. Lumbar spine movement was recorded using an inertial measurement system. The signal was temporally divided into six sections. Two outcome variables (mean absolute sway and sways per second) were calculated for each section. The reproducibility of single and averaged measurements was quantified with linear mixed-effects models and the generalizability theory. A single measurement of ten seconds duration revealed reliability coefficients of .75 for mean absolute sway and .76 for sways per second. Averaging a measurement of 40 seconds duration on two different days revealed reliability coefficients higher than .90 for both outcome variables. The outcome variables' reliability compares favourably to previously published results using different signal processing techniques or centre of pressure excursion. The introduced signal processing technique with two outcome variables to quantify joint sway during standing proved to be a highly reliable method. Since different populations, tasks or measurement tools could influence reproducibility, further investigation in other settings is still necessary. Nevertheless, the presented method has been shown to be highly promising.

Reliability of lumbar movement dysfunction tests for chronic low back pain patients.

Assessment of lumbar movement dysfunction commonly comprises trunk range of motion (ROM), movement or control impairment (MCI), and reposition error (RE). Those assessments are typically based on visual observation. Consequently it is not possible to reliably quantify back movements for intersubject comparisons, or for monitoring changes before and after an intervention. Inertial measurement unit (IMU)-systems could be used to quantify these movement dysfunctions in clinical settings. The aim of this study was to evaluate the reliability of movement dysfunction tests when measured with a novel IMU-system. The reliability of eleven movement dysfunction tests (four ROM, six MCI and one RE tests) were analysed using generalizability-theory and minimal detectable change, measuring 21 chronic low back pain patients in seven trials on two days. Reliability varied across tests and variables. Four ROM and selected MCI tests and variables were identified as reliable. On average, ROM test were more reliable, compared to MCI and RE tests. An attempt should be made to improve the reliability of MCI and RE measures, for example through better standardizations. Subsequently these measures should be studied further for intersubject comparisons and monitoring changes after an intervention.

Between-day reliability of three-dimensional motion analysis of the trunk: A comparison of marker based protocols.

Motion capture of the trunk using three-dimensional optoelectronic systems and skin markers placed on anatomical landmarks is prone to error due to marker placement, thus decreasing between-day reliability. The influence of these errors on angular output might be reduced by using an overdetermined number of markers and optimization algorithms, or by defining the neutral position using a reference trial. The purpose of this study was to quantify and compare the between-day reliability of trunk kinematics, when using these methods. In each of two sessions, 20 subjects performed four movement tasks. Trunk kinematics were established through the plug-in-gait protocol, the point cloud optimization algorithm, and by defining upright standing as neutral position. Between-day reliability was analyzed using generalizability theory and quantified by indexes of dependability. Across all movement tasks, none of the methods was superior in terms of between-day reliability. The point cloud algorithm did not improve between-day reliability, but did result in 24.3% greater axial rotation angles. The definition of neutral position by means of a reference trial revealed 5.8% higher indexes of dependability for lateral bending and axial rotation angles, but 13.7% smaller indexes of dependability for flexion angles. Further, using a reference trial resulted in 8.3° greater trunk flexion angles. Therefore, the selection of appropriate marker placement and the corresponding calculation of angular output are dependent on the movement task and the underlying research question.

Low back pain and postural control, effects of task difficulty on centre of pressure and spinal kinematics.

Association of low back pain and standing postural control (PC) deficits are reported inconsistently. Demands on PC adaptation strategies are increased by restraining the input of visual or somatosensory senses. The objectives of the current study are, to investigate whether PC adaptations of the spine, hip and the centre of pressure (COP) differ between patients reporting non-specific low back pain (NSLBP) and asymptomatic controls. The PC adaption strategies of the thoracic and lumbar spine, the hip and the COP were measured in fifty-seven NSLBP patients and 22 asymptomatic controls. We tested three "feet together" conditions with increasing demands on PC strategies, using inertial measurement units (IMUs) on the spine and a Wii balance board for centre of pressure (COP) parameters. The differences between NSLBP patients and controls were most apparent when the participants were blindfolded, but remaining on a firm surface. While NSLBP patients had larger thoracic and lumbar spine mean absolute deviations of position (MADpos) in the frontal plane, the same parameters decreased in control subjects (relative change (RC): 0.23, 95% confidence interval: 0.03 to 0.45 and 0.03 to 0.48). The Mean absolute deviation of velocity (MADvel) of the thoracic spine in the frontal plane showed a similar and significant effect (RC: 0.12 95% CI: 0.01 to 0.25). Gender, age and pain during the measurements affected some parameters significantly. PC adaptions differ between NSLBP patients and asymptomatic controls. The differences are most apparent for the thoracic and lumbar parameters of MADpos, in the frontal plane and while the visual condition was removed.

Adherence to home exercises in non-specific low back pain. A randomised controlled pilot trial.

Specific exercises for the improvement of movement control of the lumbopelvic region are well-established for patients with non-specific low back pain (NSLBP) and movement control impairment (MCI). However, a lack of adherence to home exercise regimens is often observed. The aim of the study was to explore the differences in home exercise (HE) adherence between patients who perform conventional exercises and those who exercise with Augmented Feedback (AF). Twenty patients with NSLBP and MCI were randomly allocated into two groups. The physiotherapy group (PT group) completed conventional exercises, and the AF group exercised with an AF system that was designed for use in therapy settings. The main outcome measure was self-reported adherence to the home exercise regimen. There was no significant difference in HE duration between the groups (W = 64, p = 0.315). The AF group exercised for a median of 9 min and 4 s (IQR = 3'59"), and the PT group exercised for 4 min and 19 s (IQR = 8'30"). Exercising with AF led to HE times that were similar to those of conventional exercise, and AF might be used as an alternative therapy method for home exercise.