Regional spinal kinematics and muscle activity in non-specific chronic low back pain during functional tasks: evaluation of a sub-classification approach

Background: Differences in regional lumbar angles in sitting have been observed between subclassified groups of NSCLBP patients. However, differences during standing posture, range of movement and functional tasks, as well as differences in thoracic kinematics, have not been explored to date, despite classification-based cognitive functional therapy (CB-CFT) approaches being proposed to be effective for these subgroups. Methods: Spinal kinematics and trunk muscle activity of 27 Flexion Pattern (FP), 23 Active Extension Pattern (AEP) and 28 healthy controls were recorded (using 3D motion analysis (Vicon®) and surface electromyography) during: usual sitting, usual standing, flexion, extension, sit-to-stand -to-sit, reach up, stepping up and down, lifting and replacing a box and bending (and return) to pick up a pen tasks. Midpoint regional sagittal spinal angles and normalised amplitude sEMG for trunk muscles bilaterally were compared between groups. Statistical analysis was conducted using one-way ANOVAs (kinematics) and Kruskal-Wallis (muscle activity) tests. Results: Significant differences were observed between the AEP and FP groups in the upper lumber and lower thoracic spine during most postures and tasks. Some significant differences were also observed between the FP and control groups in these regions. Additionally, significant differences in the total lumbar spine between AEP and FP groups were occasionally evident. No differences in any other spinal region (or between AEP and control groups) were observed. Some significant differences (p<0.05) in unilateral muscle activity were also observed between the NSCLBP and healthy control groups. Conclusion: The study findings further validate the classification approach (O’Sullivan, 2005). It highlighted that kinematic differences were observed to consistently occur in the thoraco-lumbar region during both static postures and functional tasks. Sub-division of regional spinal angles is key to identifying sub-group differences. These findings can inform novel CB-CFT interventions and highlights the need for targeted thoraco-lumbar spinal movement re-education strategies in NSCLBP subgroups

Regional spinal kinematics and muscle activity in non-specific chronic low back pain during functional tasks: evaluation of a sub-classification approach

Background: Differences in regional lumbar angles in sitting have been observed between subclassified groups of NSCLBP patients. However, differences during standing posture, range of movement and functional tasks, as well as differences in thoracic kinematics, have not been explored to date, despite classification-based cognitive functional therapy (CB-CFT) approaches being proposed to be effective for these subgroups. Methods: Spinal kinematics and trunk muscle activity of 27 Flexion Pattern (FP), 23 Active Extension Pattern (AEP) and 28 healthy controls were recorded (using 3D motion analysis (Vicon®) and surface electromyography) during: usual sitting, usual standing, flexion, extension, sit-to-stand -to-sit, reach up, stepping up and down, lifting and replacing a box and bending (and return) to pick up a pen tasks. Midpoint regional sagittal spinal angles and normalised amplitude sEMG for trunk muscles bilaterally were compared between groups. Statistical analysis was conducted using one-way ANOVAs (kinematics) and Kruskal-Wallis (muscle activity) tests. Results: Significant differences were observed between the AEP and FP groups in the upper lumber and lower thoracic spine during most postures and tasks. Some significant differences were also observed between the FP and control groups in these regions. Additionally, significant differences in the total lumbar spine between AEP and FP groups were occasionally evident. No differences in any other spinal region (or between AEP and control groups) were observed. Some significant differences (p<0.05) in unilateral muscle activity were also observed between the NSCLBP and healthy control groups. Conclusion: The study findings further validate the classification approach (O’Sullivan, 2005). It highlighted that kinematic differences were observed to consistently occur in the thoraco-lumbar region during both static postures and functional tasks. Sub-division of regional spinal angles is key to identifying sub-group differences. These findings can inform novel CB-CFT interventions and highlights the need for targeted thoraco-lumbar spinal movement re-education strategies in NSCLBP subgroups

Can different seating aids influence a sitting posture in healthy individuals and does gender matter?

This study determined differences in spinal-pelvic kinematics sitting on (i) mat (ii) block and (iii) novel 10º forward inclined wedge (ButtaflyTM) in a same-subject repeated measures cross-over design in 60 healthy individuals (34 females). Repeated measures ANOVA revealed statistically significant differences between sitting conditions and lumbar and pelvic sagittal angles. Both, the inclined wedge and the block seating aids reduced overall flexion, but the inclined wedge had a greater influence in the lumbar region whilst the block induced the greatest change in the pelvis. This may be relevant for seating aid design personalised to posture type. Statistically significant gender differences were identified in all 3 seating conditions with males adopting more flexed lumbar spine and posteriorly tilted pelvis. Females flexed less in thoracic spine when sitting on an inclined wedge and a block. These statistically significant differences between males and females may provide first explorative direction for bespoke seating aids design

Non-specific chronic low back pain: differences in spinal kinematics in subgroups during functional tasks

Purpose: A multidimensional classification approach suggests that motor control impairment subgroups exist in non-specific chronic low back pain (NSCLBP). Differences in sitting lumbar posture have been identified between two such subgroups [flexion pattern (FP) and active extension pattern (AEP)] and healthy individuals; however, functional spinal movement has not been explored. This study will evaluate whether NSCLBP subgroups exhibit regional spinal kinematic differences, compared to healthy individuals, during functional tasks. Methods: Observational, cross-sectional study design. Spinal kinematics of 50 NSCLBP subjects (27 FP, 23 AEP) and 28 healthy individuals were investigated using 3D motion analysis (Vicon™) during functional tasks [reaching upwards, step down, step up, lifting, and replacing a box, stand-to-sit, sit-to-stand, bending to retrieve (and returning from retrieving) a pen from the floor]. Mean sagittal angle for the total thoracic, total lumbar, upper thoracic, lower thoracic, upper lumbar, and lower lumbar regions between groups was compared. Results: Significant differences were observed in lower thoracic and upper lumbar regions between NSCLBP subgroups during most tasks. Significant differences were observed between the FP and healthy group in the lower thoracic region during stand-to-sit-to-stand tasks and bending (and returning from) to retrieve a pen from the floor. All significant results demonstrated the FP group to operate in comparatively greater flexion. Conclusions: The thoraco-lumbar spine discriminated between FP and AEP, and FP and healthy groups during functional tasks. FP individuals demonstrated more kyphotic thoraco-lumbar postures, which may be pain provocative. No significant differences were observed between AEP and healthy groups, suggesting that alternative mechanisms may occur in AEP

Investigating differences in trunk muscle activity in non-specific chronic low back pain subgroups and no-low back pain controls during functional tasks: a case-control study

Background Trunk muscle dysfunction is often regarded as a key feature of non-specific chronic low back pain (NSCLBP) despite being poorly understood and variable with increases, decreases and no change in muscle activity reported. Differences in thoraco-lumbar kinematics have been observed in motor control impairment NSCLBP subgroups (Flexion Pattern, Active Extension Pattern) during static postures and dynamic activities. However, potential differences in muscle activity during functional tasks has not been established in these subgroups to date. Methods A case-control study design recruited 50 NSCLBP subjects (27 Flexion Pattern, 23 Active Extension Pattern) and 28 healthy individuals. Surface electromyography determined muscle activity during functional tasks: reaching upwards, step-down, step-up, lifting and replacing a box, stand-to-sit, sit-to-stand, bending to retrieve (and returning from retrieving) a pen from the floor. Normalised (% sub-maximal voluntary contraction) mean amplitude electromyography of bilateral musculature (transversus abdominis/internal oblique, external oblique, superficial lumbar multifidus and longissimus thoracis) was analysed using Kruskal-Wallis and post-hoc Mann-Whitney U tests. Results Transversus abdominis/internal oblique activity was significantly increased in the Flexion Pattern group compared to controls during stand-to-sit (p=0.009) on the left side only. External oblique activity was significantly greater in the Active Extension Pattern group compared to controls during box lift (p=0.016) on the right side only. Significantly greater activity was identified in the right Superficial lumbar multifidus during step up (p=0.029), reach up (p=0.013) and box replace (p=0.007) in the Active Extension Pattern group compared to controls. However left-sided superficial lumbar multifidus activity was significantly greater in the Flexion Pattern group (compared to controls) only during stand-to-sit (p=0.009). No significant differences were observed in longissimus thoracis activity bilaterally during any task. No significant differences between NSCLBP subgroups were observed. Conclusions Muscle activity in these NSCLBP subgroups appears to be highly variable during functional tasks with no clear pattern of activity identified. The findings reflect inconsistencies and variability in trunk muscle activity previously observed in these NSCLBP subgroups. Further work evaluating ratios of muscle activity and changes in muscle activity throughout task duration is warranted. Keywords: Non-specific chronic low back pain, NSCLBP, muscle activity, trunk, functional movemen

Relationships between trunk muscle activation and thoraco-lumbar kinematics in non-specific chronic low back pain subgroups during a forward bending task

Background Trunk muscle activity and thoraco-lumbar kinematics can discriminate between non-specific chronic low back pain (NSCLBP) subgroups and healthy controls. However, research commonly focuses on lumbar kinematics, with limited understanding of relationships between kinematics and muscle activity across clinical subgroups. Similarly, the thoracic spine, whilst intuitively associated with NSCLBP, has received less attention and potential relationships between spinal regions and muscle activity requires exploration. Research question Is there a relationship between trunk muscle activation and regional thoracic and lumbar kinematics in NSCLBP subgroups during a forward bending task? Methods Observational, case-control study. Fifty subgrouped NSCLBP motor control impairment participants (27 Flexion Pattern (FP-MCI), 23 Active Extension Pattern (AEP-MCI)) and 28 pain-free controls were evaluated using 3D motion analysis (Vicon™) and surface electromyography during a forward bending and return to upright task. Mean sagittal angles for the upper-thoracic (UTx), lower-thoracic (LTx), upper-lumbar (ULx) and lower-lumbar (LLx) regions were compared with normalised (% sub-maximal voluntary contraction) mean amplitude electromyography of bilateral transversus abdominis/internal oblique, external oblique, superficial lumbar multifidus and erector spinae (longissimus thoracis) muscles between groups. Pearson correlations were computed to assess relationships (significance p < 0.01). Results AEP-MCI individuals demonstrated statistically significant relationships between superficial lumbar multifidus and ULx and LLx kinematics (−.812 to.659). FP-MCI individuals exhibited statistically significant relationships between erector spinae and superficial lumbar multifidus and LLx and LTx kinematics (−.686 to.664) in both task phases, and between external oblique and LTx during forward bending) (−.459 to.572). Correlations were moderate to strong for all significant relationships (−.812 to .664). Significance Relationships between muscle activity and regional spinal kinematics varied between NSCLBP subgroups, suggesting that those with flexion- or extension-related LBP adopt different motor control strategies when performing a bending task. As effectively mechanical biomarkers, these findings may inform treatment by improving understanding of varied motor strategies in subgroups

Global decadal variability of plant carbon isotope discrimination and its link to gross primary production

Carbon isotope discrimination (Δ13C) in C3 woody plants is a key variable for the study of photosynthesis. Yet how Δ13C varies at decadal scales, and across regions, and how it is related to gross primary production (GPP), are still incompletely understood. Here we address these questions by implementing a new Δ13C modelling capability in the land-surface model JULES incorporating both photorespiratory and mesophyll-conductance fractionations. We test the ability of four leaf-internal CO2 concentration models embedded in JULES to reproduce leaf and tree-ring (TR) carbon isotopic data. We show that all the tested models tend to overestimate average Δ13C values, and to underestimate interannual variability in Δ13C. This is likely because they ignore the effects of soil water stress on stomatal behavior. Variations in post-photosynthetic isotopic fractionations across species, sites and years, may also partly explain the discrepancies between predicted and TR-derived Δ13C values. Nonetheless, the “least-cost” (Prentice) model shows the lowest biases with the isotopic measurements, and lead to improved predictions of canopy-level carbon and water fluxes. Overall, modelled Δ13C trends vary strongly between regions during the recent (1979–2016) historical period but stay nearly constant when averaged over the globe. Photorespiratory and mesophyll effects modulate the simulated global Δ13C trend by 0.0015 ± 0.005‰ and –0.0006 ± 0.001‰ ppm−1, respectively. These predictions contrast with previous findings based on atmospheric carbon isotope measurements. Predicted Δ13C and GPP tend to be negatively correlated in wet-humid and cold regions, and in tropical African forests, but positively related elsewhere. The negative correlation between Δ13C and GPP is partly due to the strong dominant influences of temperature on GPP and vapor pressure deficit on Δ13C in those forests. Our results demonstrate that the combined analysis of Δ13C and GPP can help understand the drivers of photosynthesis changes in different climatic regions

Comparison of gait, functional activities and patient-reported outcome measures in patients with knee osteoarthritis and healthy adults using 3D motion analysis and activity monitoring: An exploratory case-control analysis

Objective: To examine functional performance differences using kinematic and kinetic analysis between participants with and without knee osteoarthritis (OA) to determine which outcomes best characterize persons with and without knee OA. Methods: Participants with unilateral moderate knee OA (Kellgren–Lawrence grades 2 or 3) and controls without knee pain were matched for age, gender, and body mass index. Primary outcomes included temporal parameters, joint rotations and moments, and ground reaction forces assessed via 3D motion capture during walking and ascending/descending stairs. Secondary outcomes included timed functional activities (sit to stand; tying shoelaces), 48 hrs lower limb activity monitoring, and patient-reported outcome measures (Knee Injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, European Quality of Life–5 Dimensions). Results: Eight matched pairs were analyzed. Compared with controls, OA participants exhibited significant reductions in peak frontal hip and sagittal knee moments, and decreased peak anterior ground reaction force with the affected limb while walking. Ascending stairs, OA participants had slower speed, fewer strides per minute, longer cycle and stance times, and increased trunk range of motion (ROM) in assessments of both limbs; longer swing time and reduced ankle ROM in the affected limb; and increased knee frontal ROM in the unaffected limb. Descending stairs, OA participants had fewer strides per minute and decreased trunk transverse ROM in assessments of both limbs; increased knee frontal ROM in the affected limb; and longer strides, shorter stance and cycle times, increased trunk sagittal and decreased knee transverse ROMs in the unaffected limbs vs controls. Compared with controls, OA participants had slower walking cadence (120–130 vs 100–110 steps/min, respectively), took significantly longer on timed functional measures, and had significantly worse scores in patient-reported outcomes. Conclusion: Several objectives and patient-reported measures examined in this study could potentially be considered as outcomes in pharmacologic or physical therapy OA trials. Keywords: osteoarthritis, knee, 3D motion analysis, biomechanics, kinetics, gai