Patients With Chronic Low Back Pain Have an Individual Movement Signature: A Comparison of Angular Amplitude, Angular Velocity and Muscle Activity Across Multiple Functional Tasks

Relationships Between Changes in Forward Bending, Pain Catastrophizing, and Pain Self-Efficacy During Cognitive Functional Therapy for People With Chronic Low Back Pain

OBJECTIVE: To investigate whether improvements in forward bending were related to reductions in pain catastrophizing (PC) and improvements in pain self-efficacy (PSE) in people with chronic low back pain (CLBP) who were undergoing cognitive functional therapy (CFT). DESIGN: Longitudinal observational study. METHODS: Two hundred sixty-one participants with CLBP received CFT. Forward bending was assessed at each treatment session over 13 weeks (average of 4.3 time points per participant [range, 1-8]). Inertial measurement units placed on T12 and S2 measured spinal range of movement (ROM) and velocity. Participants completed the Pain Catastrophizing Scale and the Pain Self-Efficacy Questionnaire online at 0, 3, 6, and 13 weeks. Multivariate, multilevel models evaluated the associations between individual rates of change over time for 3 spinal movement measures (trunk velocity, trunk ROM, and lumbar ROM) as well as PC/PSE. RESULTS: Strong correlations were observed for increased trunk velocity with reduced PC (r = -0.56; 95% confidence interval [CI]: -0.82, -0.01) and increased PSE (r = 0.63; 95% CI: 0.18, 0.87). There was no evidence of an association between changes in trunk ROM and PC (r = -0.06; 95% CI: 0.38, 0.28) or PSE (r = 0.36; 95% CI: -0.27, 0.65) as well as no evidence of an association between lumbar ROM and PC (r = -0.07; 95% CI: -0.63, 0.55) or PSE (r = 0.16; 95% CI: -0.49, 0.69). CONCLUSION: Improvements in PC and PSE were strongly correlated with increased trunk velocity-but not trunk or lumbar ROM-in people with CLBP who were undergoing CFT. These findings are consistent with CFT that explicitly trains "nonprotective" spinal movement in conjunction with positively reframing pain cognitions. J Orthop Sports Phys Ther 2025;55(4):1-11. Epub 12 March 2025. doi:10.2519/jospt.2025.13114.

Improvements in Forward Bending Are Related to Improvements in Pain and Disability During Cognitive Functional Therapy for People With Chronic Low Back Pain

OBJECTIVE: To investigate whether improvements in forward bending were related to improvements in pain and disability in people with chronic low back pain (CLBP) who were undergoing Cognitive Functional Therapy (CFT). DESIGN: Longitudinal observational study. METHODS: Two hundred and sixty-one participants with CLBP received CFT. Forward bending was assessed at each treatment session over 13 weeks (an average of 4.3 timepoints per participant [range, 1-8]). Spinal range of motion (ROM) and velocity were recorded using 2 inertial measurement units located at T12 and S2. Participants reported (1) average pain intensity (0-10 scale) (pain) and (2) pain-related activity limitation (Roland Morris Disability Questionnaire [disability]) via online questionnaires at 0, 3, 6, and 13 weeks. Multivariate multilevel models were used to evaluate associations between individual rates of change over time for 3 spinal movement measures (trunk velocity, trunk ROM, lumbar ROM) and pain/disability. RESULTS: Strong correlations were observed for increased trunk velocity with reduced pain (r = -0.81; 95% CI: -0.98, -0.05) and with reduced disability (r = -0.77; 95% CI: -0.95, -0.22). Moderate correlations were observed between increased trunk ROM with reduced pain (r = -0.37; 95% CI: -0.67, 0.04) and with reduced disability (r = -0.32; 95% CI: -0.6, 0.03). There was no evidence of association between changes in lumbar ROM and pain (r = -0.46; 95% CI: -0.90, 0.44) or disability (r = -0.01; 95% CI: -0.56, 0.55). CONCLUSION: Reductions in pain and disability were strongly correlated with increased trunk velocity in people with CLBP who were undergoing CFT. These findings are consistent with CFT that explicitly trains "nonprotective" spinal movement. J Orthop Sports Phys Ther 2024;54(11):721-731. Epub 7 October 2024. doi:10.2519/jospt.2024.12727.

Quantifying lumbar mobility using a single tri-axial accelerometer

Background

Lumbar mobility is regarded as important for assessing and managing low back pain (LBP). Inertial Measurement Units (IMUs) are currently the most feasible technology for quantifying lumbar mobility in clinical and research settings. However, their gyroscopes are susceptible to drift errors, limiting their use for long-term remote monitoring.

Research question

Can a single tri-axial accelerometer provide an accurate and feasible alternative to a multi-sensor IMU for quantifying lumbar flexion mobility and velocity?

Methods

In this cross-sectional study, 18 healthy adults performed nine repetitions of full spinal flexion movements. Lumbar flexion mobility and velocity were quantified using a multi-sensor IMU and just the tri-axial accelerometer within the IMU. Correlations between the two methods were assessed for each percentile of the lumbar flexion movement cycle, and differences in measurements were modelled using a Generalised Additive Model (GAM).

Results

Very high correlations (r > 0.90) in flexion angles and velocities were found between the two methods for most of the movement cycle. However, the accelerometer overestimated lumbar flexion angle at the start (-4.7° [95 % CI -7.6° to -1.8°]) and end (-4.8° [95 % CI -7.7° to -1.9°]) of movement cycles, but underestimated angles (maximal difference of 4.3° [95 % CI 1.4° to 7.2°]) between 7 % and 92 % of the movement cycle. For flexion velocity, the accelerometer underestimated at the start (16.6°/s [95%CI 16.0 to 17.2°/s]) and overestimated (-12.3°/s [95%CI -12.9 to -11.7°/s]) at the end of the movement, compared to the IMU.

Significance

Despite the observed differences, the study suggests that a single tri-axial accelerometer could be a feasible tool for continuous remote monitoring of lumbar mobility and velocity. This finding has potential implications for the management of LBP, enabling more accessible and cost-effective monitoring of lumbar mobility in both clinical and research settings.

BACK-to-MOVE: Machine learning and computer vision model automating clinical classification of non-specific low back pain for personalised management

BACKGROUND

Low back pain (LBP) is a major global disability contributor with profound health and socio-economic implications. The predominant form is non-specific LBP (NSLBP), lacking treatable pathology. Active physical interventions tailored to individual needs and capabilities are crucial for its management. However, the intricate nature of NSLBP and complexity of clinical classification systems necessitating extensive clinical training, hinder customised treatment access. Recent advancements in machine learning and computer vision demonstrate promise in characterising NSLBP altered movement patters through wearable sensors and optical motion capture. This study aimed to develop and evaluate a machine learning model (i.e., 'BACK-to-MOVE') for NSLBP classification trained with expert clinical classification, spinal motion data from a standard video alongside patient-reported outcome measures (PROMs).

METHODS

Synchronised video and three-dimensional (3D) motion data was collected during forward spinal flexion from 83 NSLBP patients. Two physiotherapists independently classified them as motor control impairment (MCI) or movement impairment (MI), with conflicts resolved by a third expert. The Convolutional Neural Networks (CNNs) architecture, HigherHRNet, was chosen for effective pose estimation from video data. The model was validated against 3D motion data (subset of 62) and trained on the freely available MS-COCO dataset for feature extraction. The Back-to-Move classifier underwent fine-tuning through feed-forward neural networks using labelled examples from the training dataset. Evaluation utilised 5-fold cross-validation to assess accuracy, specificity, sensitivity, and F1 measure.

RESULTS

Pose estimation's Mean Square Error of 0.35 degrees against 3D motion data demonstrated strong criterion validity. Back-to-Move proficiently differentiated MI and MCI classes, yielding 93.98% accuracy, 96.49% sensitivity (MI detection), 88.46% specificity (MCI detection), and an F1 measure of .957. Incorporating PROMs curtailed classifier performance (accuracy: 68.67%, sensitivity: 91.23%, specificity: 18.52%, F1: .800).

CONCLUSION

This study is the first to demonstrate automated clinical classification of NSLBP using computer vision and machine learning with standard video data, achieving accuracy comparable to expert consensus. Automated classification of NSLBP based on altered movement patters video-recorded during routine clinical examination could expedite personalised NSLBP rehabilitation management, circumventing existing healthcare constraints. This advancement holds significant promise for patients and healthcare services alike.

How Movement Is Assessed Matters. Changes in Forward Bending During Cognitive Functional Therapy Treatment for People With Chronic Low Back Pain

OBJECTIVE: To investigate forward bending range of motion (ROM) and velocity in patients with low back pain who were receiving Cognitive Functional Therapy and determine (1) the amount and timing of change occurring at the trunk and pelvis (global angles), and lumbar spine (intersensor angle), and (2a) differences in changes between participants with and without sensor biofeedback, and (2b) participants with and without baseline movement limitation. DESIGN: Observational study. METHODS: Two hundred sixty-one participants attended Cognitive Functional Therapy treatment and wore sensors at the T12 and S2 spine levels while performing forward bending. Measures included ROM and velocity from both sensors, and the intersensor angle. Regression models estimated changes over time. Time-group interactions tested participants who were subgrouped by treatment and baseline movement. RESULTS: During the 90-day evaluation period, most change occurred in the first 21 days. Changes in ROM observed at T12 (3.3°, 95% CI: 1.0°, 5.5°; P = .001) and S2 (3.3°, 95% CI: 1.2°, 5.4°; P = .002) were similar. Intersensor angle remained similar (0.2°, 95% CI: -2.0°, -1.6°; P = .81). Velocity measured at T12 and S2, and the intersensor angle increased 8.5°/s (95% CI: 6.7°/s, 10.3°/s; P<.0001), 5.3°/s (95% CI: 4.0°/s, 6.5°/s; P<.0001), and 3.4°/s (95% CI: 2.4°/s, 4.5°/s; P<.0001), respectively, for 0 to 21 days. There were minimal differences in participants who received biofeedback. Larger increases occurred in participants with restricted ROM and slower velocity at baseline. CONCLUSION: During 0 to 21 days, we observed changes at the trunk and pelvis (especially in people with reduced ROM), and velocity changes across all measures (especially in people with baseline movement limitations). Biofeedback did not augment the changes. When targeting forward bending in people with low back pain, clinicians should monitor changes in velocity and global ROM. J Orthop Sports Phys Ther 2024;54(3):1-13. Epub 19 December 2023. doi:10.2519/jospt.2023.12023.

Determinants of outcomes for patients with chronic low back pain and fear-avoidance beliefs following treatment with specific stabilisation exercises

BACKGROUND

Specific stabilisation exercises (SSE) can combat the debilitating effects of chronic non-specific low back pain (CLBP), improve disability, pain and fear-avoidance beliefs (FAB).

OBJECTIVE

To elicit the determinants of outcome in patients with CLBP with associated FABs after treatment with SSE.

METHOD

Twenty-nine patients (20 females) with CLBP were classified using FAB questionnaire into high or low Work and Physical Activity (PA) subscales. After 4-week treatment, evaluations were done for pain, disability and lumbar spine active range of motion (AROM). Data was analysed exploratory-descriptively with a significance level set at p< 0.05.

RESULTS

Participants were aged 55.24 ± 11.91 years. They scored 19 (65.5%) and 5 (17.2%) respectively on Work and PA subscales. The post-intervention evaluation showed significant differences in all outcomes, but no significant difference between patients with high or low FAB scores for both subscales. PA scores correlated significantly with pain while work scores correlated significantly with disability. Participants' gender predicted disability, pain and AROM with moderate to large effect sizes.

CONCLUSION

SSE can potentially improve disability, pain and range of motion for patients with chronic low back pain regardless of FABQ status. Gender and baseline patient status are potential determinants of outcome of treatment using SSE.

The relationships between spinal amplitude of movement, pain and disability in low back pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The role of spinal movement alterations in low back pain (LBP) remains unclear. This systematic review and meta-analyses examined the relationships between spinal amplitude of movement, disability and pain intensity in patients with LBP.

DATABASES AND DATA TREATMENT

We searched PubMed, CINAHL, Embase, Pedro and Web of Science for relevant articles until 14th March 2023. Risk of bias was assessed with the Quality in Prognostic Studies Tool. We analysed the relationships between amplitude of movement, disability and pain intensity with standard correlational meta-analyses and meta-analytic structural equation modelling (MASEM) in cross-sectional and longitudinal data.

RESULTS

A total of 106 studies (9001 participants) were included. In cross-sectional data, larger amplitude of movement was associated with lower disability (pooled coefficient: -0.25, 95% confidence interval: [-0.29 to -0.21]; 69/5899 studies/participants) and pain intensity (-0.13, [-0.17 to -0.09]; 74/5806). An increase in amplitude of movement was associated with a decrease in disability (-0.23, [-0.31 to -0.15]; 33/2437) and pain intensity (-0.25, [-0.33 to -0.17]; 38/2172) in longitudinal data. MASEM revealed similar results and, in addition, showed that amplitude of movement had a very small influence on the pain intensity-disability relationship.

CONCLUSIONS

These results showed a significant but small association between amplitude of movement and disability or pain intensity. Moreover, they demonstrated a direct association between an increase in amplitude of movement and a decrease in pain intensity or disability, supporting interventions aiming to reduce protective spinal movements in patients with LBP.

SIGNIFICANCE

The large meta-analyses performed in this work revealed an association between reductions in spinal amplitude of movement and increased levels of disability and pain intensity in people with LBP. Moreover, it highlighted that LBP recovery is associated with a reduction in protective motor behaviour (increased amplitude of movement), supporting the inclusion of spinal movement in the biopsychosocial understanding and management of LBP.

Validity of evaluating spinal kinetics without participant-specific kinematics

Musculoskeletal models are commonly used to estimate in vivo spinal loads under various loading conditions. Typically, participant-specific measured kinematics (PSMK) are coupled with participant-specific models, but obtaining PSMK data can be costly and infeasible in large studies or clinical practice. Thus, we evaluated two alternative methods to estimate spinal loads without PSMK: 1) ensemble average kinematics (EAK) based on kinematics from all participants; and 2) using separately measured individual kinematics (SMIK) from multiple other participants as inputs, then averaging the resulting loads. This study compares the dynamic spine loading patterns and peak loads in older adults performing five lifting tasks using PSMK, EAK and SMIK. Median root mean square errors of EAK and SMIK methods versus PSMK ranged from 18 to 72% body weight for compressive loads and from 2 to 25% body weight for shear loads, with median cross-correlations ranging from 0.931 to 0.991. The root mean square errors and cross-correlations between repeated PSMK trials fell within similar ranges. Compressive peak loads evaluated by EAK and SMIK were not different than PSMK in 12 of 15 cases, while by comparison repeated PSMK trials were not different in 13 of 15 cases. Overall, the resulting spine loading magnitudes and profiles using EAK or SMIK were not notably different than using a PSMK approach, and differences were not greater than between two PSMK trials. Thus, these findings indicate that these approaches may be used to make reasonable estimates of dynamic spinal loading without direct measurement of participant kinematics.

Reduction in pain-related fear is not associated with improvement in spinal biomechanics but with decrease in movement-evoked pain in patients with chronic low back pain

BACKGROUND AND AIMS

While a causal relationship between pain-related fear and spinal movement avoidance in patients with chronic low back pain (CLBP) has frequently been postulated, evidence supporting this relationship is limited. This study aimed to test if decreases in pain-related fear or catastrophizing were associated with improvements in spinal biomechanics, accounting for possible changes in movement-evoked pain.

METHODS

Sixty-two patients with CLBP were assessed before and after an interdisciplinary rehabilitation program (IRP). Pain-related fear was assessed with general and task-specific measures. Lower and upper lumbar angular amplitude and velocity as well as paraspinal muscle activity were recorded during five daily-life tasks to evaluate spinal biomechanics. Relationships were tested with multivariable linear regression analyses.

RESULTS

The large decreases in pain-related fear and catastrophizing following the IRP were scarcely and inconsistently associated with changes in spinal biomechanics (< 3% of the models reported a statistically significant association). Results remained comparable for activities inducing more or less fear, for specific or general measures of pain-related fear, and for analyses performed on the entire population or limited to subgroups of patients with higher levels of task-specific fear. In contrast, reductions in task-specific pain-related fear were significantly associated with decreases in movement-evoked pain in all tasks (r = 0.26-0.62, p ≤ 0.02).

CONCLUSION

This study does not support an association between pain-related fear and spinal movement avoidance. However, it provides evidence supporting a direct relationship between decreased pain-related fear and decreased movement-evoked pain, possibly explaining some mechanisms of the rehabilitation programs.

Concurrent validity of DorsaVi wireless motion sensor system Version 6 and the Vicon motion analysis system during lifting

Background

Wearable sensor technology may allow accurate monitoring of spine movement outside a clinical setting. The concurrent validity of wearable sensors during multiplane tasks, such as lifting, is unknown. This study assessed DorsaVi Version 6 sensors for their concurrent validity with the Vicon motion analysis system for measuring lumbar flexion during lifting.

Methods

Twelve participants (nine with, and three without back pain) wore sensors on T12 and S2 spinal levels with Vicon surface markers attached to those sensors. Participants performed 5 symmetrical (lifting from front) and 20 asymmetrical lifts (alternate lifting from left and right). The global-T12-angle, global-S2-angle and the angle between these two sensors (relative-lumbar-angle) were output in the sagittal plane. Agreement between systems was determined through-range and at peak flexion, using multilevel mixed-effects regression models to calculate root mean square errors and standard deviation. Mean differences and limits of agreement for peak flexion were calculated using the Bland Altman method.

Results

For through-range measures of symmetrical lifts, root mean squared errors (standard deviation) were 0.86° (0.78) at global-T12-angle, 0.90° (0.84) at global-S2-angle and 1.34° (1.25) at relative-lumbar-angle. For through-range measures of asymmetrical lifts, root mean squared errors (standard deviation) were 1.84° (1.58) at global-T12-angle, 1.90° (1.65) at global-S2-angle and 1.70° (1.54) at relative-lumbar-angle. The mean difference (95% limit of agreement) for peak flexion of symmetrical lifts, was − 0.90° (-6.80 to 5.00) for global-T12-angle, 0.60° (-2.16 to 3.36) for global-S2-angle and − 1.20° (-8.06 to 5.67) for relative-lumbar-angle. The mean difference (95% limit of agreement) for peak flexion of asymmetrical lifts was − 1.59° (-8.66 to 5.48) for global-T12-angle, -0.60° (-7.00 to 5.79) for global-S2-angle and − 0.84° (-8.55 to 6.88) for relative-lumbar-angle.

Conclusion

The root means squared errors were slightly better for symmetrical lifts than they were for asymmetrical lifts. Mean differences and 95% limits of agreement showed variability across lift types. However, the root mean squared errors for all lifts were better than previous research and below clinically acceptable thresholds. This research supports the use of lumbar flexion measurements from these inertial measurement units in populations with low back pain, where multi-plane lifting movements are assessed.