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

Estimating Compressive and Shear Forces at L5-S1: Exploring the Effects of Load Weight, Asymmetry, and Height Using Optical and Inertial Motion Capture Systems

This study assesses the agreement of compressive and shear force estimates at the L5-S1 joint using inertial motion capture (IMC) within a musculoskeletal simulation model during manual lifting tasks, compared against a top-down optical motion capture (OMC)-based model. Thirty-six participants completed lifting and lowering tasks while wearing a modified Plug-in Gait marker set for the OMC and a full-body IMC set-up consisting of 17 sensors. The study focused on tasks with variable load weights, lifting heights, and trunk rotation angles. It was found that the IMC system consistently underestimated the compressive forces by an average of 34% (975.16 N) and the shear forces by 30% (291.77 N) compared with the OMC system. A critical observation was the discrepancy in joint angle measurements, particularly in trunk flexion, where the IMC-based model underestimated the angles by 10.92-11.19 degrees on average, with the extremes reaching up to 28 degrees. This underestimation was more pronounced in tasks involving greater flexion, notably impacting the force estimates. Additionally, this study highlights significant differences in the distance from the spine to the box during these tasks. On average, the IMC system showed an 8 cm shorter distance on the X axis and a 12-13 cm shorter distance on the Z axis during lifting and lowering, respectively, indicating a consistent underestimation of the segment length compared with the OMC system. These discrepancies in the joint angles and distances suggest potential limitations of the IMC system's sensor placement and model scaling. The load weight emerged as the most significant factor affecting force estimates, particularly at lower lifting heights, which involved more pronounced flexion movements. This study concludes that while the IMC system offers utility in ergonomic assessments, sensor placement and anthropometric modeling accuracy enhancements are imperative for more reliable force and kinematic estimations in occupational settings.

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.

Identifying Clinical Phenotypes in People Who Are Hispanic/Latino With Chronic Low Back Pain: Use of Sensor-Based Measures of Posture and Movement, Pain, and Psychological Factors

OBJECTIVE

The aim of this study was to identify clinical phenotypes using sensor-based measures of posture and movement, pain behavior, and psychological factors in Hispanic/Latino people with chronic low back pain (CLBP).

METHODS

Baseline measures from an ongoing clinical trial were analyzed for 81 Hispanic/Latino people with CLBP. Low back posture and movement were measured using commercial sensors during in-person testing and 8 hours of ecological monitoring. Magnitude, frequency, and duration of lumbar movements, sitting and standing postures were measured. Movement-evoked pain was assessed during in-person movement testing. Psychological measures included the Pain Catastrophizing Scale and the Fear Avoidance Beliefs Questionnaire. Random forest analysis was conducted to generate 2 groups and identify important variables that distinguish groups. Group differences in demographics, pain, psychological, and posture and movement variables were examined using t-tests and chi-square analyses.

RESULTS

Two subgroups of Hispanic/Latino people with CLBP were identified with minimal error (7.4% misclassification ["out-of-bag" error]). Ecological posture and movement measures best distinguished groups, although most movement-evoked pain and psychological measures did not. Group 1 had greater height and weight, lower movement frequency, more time in sitting, and less time in standing. Group 2 had a greater proportion of women than men, longer low back pain duration, higher movement frequency, more time in standing, and less time in sitting.

CONCLUSION

Two distinct clinical phenotypes of Hispanic/Latino people with CLBP were identified. One group was distinguished by greater height and weight and more sedentary posture and movement behavior; the second group had more women, longer duration of low back pain, higher lumbar spine movement frequency, and longer duration of standing postures.

IMPACT

Ecological measures of posture and movement are important for identifying 2 clinical phenotypes in Hispanic/Latino people with CLBP and may provide a basis for a more personalized plan of care.

LAY SUMMARY

Wearable sensors were used to measure low back posture and movement in Hispanic/Latino people with chronic low back pain. These posture and movement measures helped to identify 2 different clinical subgroups that will give physical therapists more information to better personalize treatment for chronic low back pain in Hispanic/Latino patients.