Development of a cost effective three-dimensional posture analysis tool: validity and reliability

Repeatability of Motion Health Screening Scores Acquired from a Three-Dimensional Markerless Motion Capture System

The purpose of the present study was to examine the repeatability of five algorithm-derived motion health screening scores (i.e., readiness, explosiveness, functionality, quality, and dysfunction) obtained from an innovative three-dimensional markerless motion capture system, composed of eight high-definition cameras recording at 60 fps. Thirteen females and six males performed two sets of three motion capture screenings, separated one week apart (six in total). The screenings consisted of 20 body movements performed in sequential order. Each screening within a testing session was separated by a 30 min rest interval to avoid the possible influence of fatigue. A trained research team member, facing the participant and standing outside of the camera capture range, was present to demonstrate each individual movement. The order in which motions were performed was identical across all participants. Repeated measures analysis of variance and intraclass correlation coefficients were used to examine statistically significant differences and measurement agreement across six testing sessions. The findings of the present study revealed no significant differences in algorithm-based motion health screening scores across multiple testing sessions. Moreover, excellent measurement reliability was found for readiness scores (ICC, 95% CI; 0.957, 0.914-0.980), good-to-excellent for functionality (0.905, 0.821-0.959) and explosiveness scores (0.906, 0.822-0.959), and moderate-to-excellent for dysfunction (0.829, 0.675-0.925) and quality scores (0.808, 0.635-0.915).

Quality and usability of clinical assessments of static standing and sitting posture: A systematic review

BACKGROUND

A validated method to assess sitting and standing posture in a clinical setting is needed to guide diagnosis, treatment and evaluation of these postures. At present, no systematic overview of assessment methods, their clinimetric properties, and usability is available.

OBJECTIVE

The objective of this study was to provide such an overview and to interpret the results for clinical practice.

METHODS

A systematic literature review was performed according to international guidelines. Two independent reviewers assessed risk of bias, clinimetric values of the assessment methods, and their usability. Quality of evidence and strength of recommendations were determined according to the Grading of Recommendations Assessment, Development and Evaluation working group (GRADE).

RESULTS

Out of 27,680 records, 41 eligible studies were included. Thirty-two assessment instruments were identified, clustered into five categories. The methodological quality of 27 (66%) of the articles was moderate to good. Reliability was most frequently studied. Little information was found about validity and none about responsiveness.

CONCLUSIONS

Based on a moderate level of evidence, a tentative recommendation can be made to use a direct visual observation method with global posture recorded by a trained observer applying a rating scale.

Sitting Posture during Prolonged Computer Typing with and without a Wearable Biofeedback Sensor

Prolonged sitting combined with an awkward posture might contribute to the increased risks of developing spinal pain. Maintaining an upright sitting posture is thus often suggested, especially nowadays when people spend longer periods in the sitting posture for occupational or leisure activities. Many types of assistive devices are commercially available to help computer users maintain an upright sitting posture. As the technology advances, wearable sensors that use microelectromechanical technology are designed to provide real-time biofeedback and promote adjusting posture actively. However, whether such wearable biofeedback sensors could assist adjusting sitting posture in computer users during prolonged typing remains unknown. This study aimed to investigate the effects of a wearable biofeedback sensor on maintaining an upright sitting posture. Twenty-one healthy young adults were recruited and performed a 1-h computer typing task twice, with and without using the active biofeedback device. The sagittal spinal posture during computer typing was measured using a three-dimensional motion analysis system. Using the wearable biofeedback sensor significantly decreased the neck flexion (p < 0.001), thoracic kyphotic (p = 0.033), and pelvic plane (p = 0.021) angles compared with not using the sensor. Computer users and sedentary workers may benefit from using wearable biofeedback sensors to actively maintain an upright sitting posture during prolonged deskwork.

Craniocervical flexion performance in computer users: An observational study

Study aim: To compare the performance of deep cervical flexors (DCF) among computer users (CU) and non-users using the craniocervical flexion test (CCFT).

Material and methods: Eighty nine computer users and 100 non-users were recruited for evaluation of their craniocervical muscle performance. The activation score and performance index were assessed using the CCFT. Comparison of craniocervical flexor performance between the two groups was evaluated using the Mann Whitney test. A Chi-Square test was used to test the association between age, years of work and craniocervical flexion. Significance was set at p ≤ 0.05.

Results: The median activation score was lower among computer users (median pressure-24 mmHg as compared to non-users (median pressure-28 mmHg) (p < 0.01). The performance index among computer users was lower when compared to non-users. Also, age (p < 0.001) and the years of work experience (p = 0.006) were associated with the DCF performance.

Conclusion: CU have lower activation and endurance of the DCF compared to non-users. The endurance of the DCF was associated with the age and years of computer usage.

Joint position sense in individuals with anterior knee pain

BACKGROUND

Anterior knee pain (AKP) commonly affects both physically active and sedentary individuals and the aetiology is unknown. Altered joint position sense (JPS) impacts accurate motor action and knee joint stability. It is unclear whether people with AKP have altered JPS.

OBJECTIVE

The aim of our study was to investigate JPS in the knees of individuals with AKP.

METHOD

A descriptive cross-sectional study measured JPS in 25 participants with unilateral or bilateral AKP. JPS was measured using active JPS testing during single leg squat (SLS) and active knee extension (AKE) in sitting. Target angles (TA) were self-determined based on each participant's capabilities. The absolute error (AE) was the main outcome measure. Impaired JPS was classified as an AE equal to or greater than five degrees.

RESULTS

There were no significant differences in JPS when comparing the affected and unaffected knees in participants with AKP (p > 0.05). However, a subgroup of participants with altered knee JPS was identified. There was a tendency towards greater knee flexion in the TAs of knees without AKP.

CONCLUSION

Our results showed that JPS is not significantly more impaired in knees with AKP compared with knees without AKP in a group of individuals with AKP. A subgroup with altered JPS in knees with and without AKP was identified. This finding could be because of compensatory gait patterns and the precision of the Vicon 3D motion analysis system.

CLINICAL IMPLICATIONS

Joint position sense should be assessed bilaterally in individuals with AKP.

Do changes in psychosocial factors, lifestyle factors and sitting posture influence the likelihood of musculoskeletal pain in high school computer users?

OBJECTIVES

Adolescents regularly engage in screen-based activities. Complex factors influence adolescents' growth, and habitual sitting posture. The association between over-time changes in their sitting posture, and upper quadrant musculoskeletal pain (UQMP) is poorly understood. This study tested the association between change over 12 months in seated posture angles (neck flexion [NF]; craniocervical angle [CCA] into flexion and extension; and thoracic flexion [TF]), UQMP, and predictor variables (anxiety and depression; sport activity, music participation; computer use).

METHODS

A one-year prospective longitudinal study enrolled 211 asymptomatic 15-18-year students. 3D motion analysis captured postural angles while students worked on desktop computers, at baseline and 12 months later. Height, weight, computing time, sport and music participation, and depression and anxiety were measured at both time periods. UQMP in the previous month was captured at 12 months. The association between over-time change in sitting posture angles and predictor variables was determined using linear regression analysis (r² ; p-values). The association between predictor variables with UQMP, and predictor variables on the association between postural angles and UQMP was assessed using logistic regression models (Odds Ratios [95%CI]). Significant confounding effects were determined when the addition of a predictor variable to the posture-UQMP model significantly changed the Likelihood Ratio chi square value.

RESULTS

N = 153 students (72%) completed the study (48 with UQMP). Significant associations occurred between head flexion (HF) and body mass index (BMI) (r²⁼ 4.20, p = .01); NF and computer use (r²⁼ 2.87, p = .036) and CCA and music participation (r²⁼ 9.99, p = .047). Music participants and non-participants in sport or music had increased risk of UQMP with CCA changes into flexion (OR 12.0) and TF changes into extension (OR 7.6) respectively.

CONCLUSION

The association between over-time-change in sitting posture angles and UQMP is not influenced by anthropometrics, psychosocial factors or time spent computing. Music students, and students not participating in sport, require further postural analysis.

Current Low-Cost Video-Based Motion Analysis Options for Clinical Rehabilitation: A Systematic Review

BACKGROUND

Physical therapists, as clinical human movement experts, must qualitatively evaluate patients' functional and biomechanical impairments. There are now low-cost 2- and 3-dimensional video measurement systems that can be used to increase the precision and reliability of these qualitative clinical assessments.

PURPOSE

The purpose of this study was to systematically review current low-cost video-based methods for motion analysis compared with gold-standard 3-dimensional biomechanical methods.

DATA SOURCES

Electronic searches were conducted until January 2018 within the following databases: MEDLINE via PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane, Scopus, and the Institute of Electrical and Electronics Engineers.

STUDY SELECTION

Studies designed to evaluate criterion-referenced validity and/or reliability of video-based motion analysis technologies within the last 20 years were included. English-language articles dealing with human rehabilitation were considered.

DATA EXTRACTION

Data extraction was independently completed by 3 reviewers, and methodological quality was assessed using the 2018 Consensus-Based Standards for the Selection of Health Measurement Instruments checklist. Articles were organized for analysis on the basis of type of motion analyzed and category of each low-cost technology used.

DATA SYNTHESIS

With 20 articles meeting selection criteria, 10 low-cost motion analysis platforms were presented, each examining different functional movement-dependent variables. Overall article quality was "low" or "very low" on the basis of Consensus-Based Standards for the Selection of Health Measurement Instruments scoring. Correlations between low-cost and 3-dimensional gold standard systems ranged widely from "poor" agreement (r = 0.025) to "strong" agreement (r = 0.992). Spatiotemporal gait parameters consistently outperformed planar joint angle data. Reliability was better measured than concurrent validity. A summary table was developed to assist clinicians in choosing which motions could potentially be measured accurately by each low-cost platform on the basis of current findings.

LIMITATIONS

Databases available to researchers were more clinical/medical in nature, and this review was written from that clinically based perspective. Lack of standardized protocols and methodology within included studies was common, making generalizability difficult.

CONCLUSIONS

Research attempting to validate newer low-cost movement analysis systems is limited in quality. Measurement of only certain variables should be considered when these tools are used. Further research is warranted, because these devices still have potential clinical utility for supplementing qualitative movement assessment with objective outcome measures.

Validity and Reliability of Standing Posture Measurements Using a Mobile Application

OBJECTIVE

The purpose of this study was to evaluate the validity and reliability of standing posture assessments in asymptomatic men using the PostureScreen Mobile (PSM) iOS application.

METHODS

The standing posture of 50 asymptomatic male participants (24.04 ± 1.81 years) was measured during 3 trials on the same day. The following 10 measurements using the PSM app were compared to the criterion VICON 3-dimensional analysis: from the frontal plane, shift and tilt of the head, shoulders, and hips; and from the sagittal plane, shift of the head, shoulders, hips, and knees. We used Bayesian methods to analyze the data.

RESULTS

Compared with the VICON measurements, PSM assessments of head tilt, shoulder tilt and shift, and hip tilt and shift in the frontal plane were biased. In the sagittal plane, PSM measurements of shoulder, hip, and knee shift were biased. Only head shift in the frontal and sagittal planes were comparable between the VICON and the PSM. The VICON and PSM had similar intraclass correlations in 6 of 10 measurements. The PSM assessments of head shift and tilt and shoulder tilt in the sagittal plane were significantly less reliable than with VICON.

CONCLUSION

The use of the PSM app introduced significant bias in postural measurements in the frontal and sagittal plane. Until further research reports additional validity and reliability data of the PSM app, we suggest caution in the use of PSM app when highly accurate postural assessments are necessary.

The amount of postural change experienced by adolescent computer users developing seated -related upper quadrant musculoskeletal pain

BACKGROUND

Improved techniques of measuring sitting posture have not led to a more comprehensive understanding of poor posture, nor its association with pain. There is also an evidence gap regarding critical thresholds of sitting postural change over time related to pain production. This paper describes postural angle changes over a 12-month period, and describes the process of placing defensible cut-points in the angle change data, to better understand associations between posture change over time, and onset of upper quadrant musculoskeletal pain (UQMP).

METHODS

This paper reports on data captured at baseline and 12-month follow-up, in adolescents in school using computers. Four sitting postural angles, head flexion (HF), neck flexion (NF), craniocervical angle (CCA) and trunk flexion (TF), and self-reported seated UQMP in the previous month were captured at each time-point. Research questions were: 1) What is the magnitude and direction of change in each postural angle over 12 months? 2) What are best cut-points in the continuous posture change distribution to most sensitively test the association between posture change and UQMP? 3) Is gender-specific cut-points required? The 12-month posture angle change data was divided into quintiles (0-20th%; 21-40^th%, 41-60^th%, 61-80^th%, >80^th%), and the odds of UQMP occurring in each posture change quintile were calculated using logistic regression models.

RESULTS

Two hundred and eleven students participated at baseline, of which 153 were followed-up at one year. Both males and females with postural change into extension (which represents lesser flexion range) were more at risk for the development of UQMP, than any other group. The best cut-point for HF was 40^th% (≤-3.9°), NF was 20th% (≤-2.9°) and TF was 40^th% (≤-1.1°). For CCA however, change at or beyond 40^th % for extension or beyond 60% for flexion was associated with UQMP.

CONCLUSIONS

Identification of critical postural angle change cut-points assists in considering the pain-producing mechanisms for adolescents using desk top computers.

Concordance and Reliability of Photogrammetric Protocols for Measuring the Cervical Lordosis Angle: A Systematic Review of the Literature

OBJECTIVE

The aim of this study was to examine and interpret the concordance, accuracy, and reliability of photogrammetric protocols available in the literature for evaluating cervical lordosis in an adult population aged 18 to 59 years.

METHODS

A systematic search of 6 electronic databases (MEDLINE via PubMed, LILACS, CINAHL, Scopus, ScienceDirect, and Web of Science) located studies that assessed the reliability and/or concordance and/or accuracy of photogrammetric protocols for evaluating cervical lordosis, compared with radiography. Articles published through April 2016 were selected. Two independent reviewers used a critical appraisal tool (QUADAS and QAREL) to assess the quality of the selected studies.

RESULTS

Two studies were included in the review and had high levels of reliability (intraclass correlation coefficient: 0.974-0.98). Only 1 study assessed the concordance between the methods, which was calculated using Pearson's correlation coefficient. To date, the accuracy of photogrammetry has not been investigated thoroughly.

CONCLUSION

We encountered no study in the literature that investigated the accuracy of photogrammetry in diagnosing hyperlordosis of cervical spine. However, both current studies report high levels of intra- and interrater reliability. To increase the level of evidence of photogrammetry in the evaluation of cervical lordosis, it is necessary to conduct further studies using a larger sample to increase the external validity of the findings.

Intrarater and Inter-rater Reliability of Active Cervical Range of Motion in Patients With Nonspecific Neck Pain Measured With Technological and Common Use Devices: A Systematic Review With Meta-regression

OBJECTIVES

The purpose of this systematic review was to compare intrarater and inter-rater reliability of active cervical range of motion (ACROM) measures obtained with technological devices to those assessed with low-cost devices in patients with nonspecific neck pain. As a secondary outcome, we investigated if ACROM reliability is influenced by the plane of the assessed movement.

METHODS

Medline, Scopus, Embase, the Cochrane Library, CINHAL, PEDro, and gray literature were searched until August 2016. Inclusion criteria were reliability design, population of adults with nonspecific neck pain, examiners of any level of experience, measures repeated at least twice, and statistical indexes on reliability. A device was considered inexpensive if it cost less than €500. The risk of bias of included studies was assessed by Quality Appraisal of Reliability Studies.

RESULTS

The search yielded 35 151 records. Nine studies met all eligibility criteria. Their Quality Appraisal of Reliability Studies mean score was 3.7 of 11. No significant effect of the type of device (inexpensive vs expensive) on intraclass correlation coefficient (ICC) was identified for intrarater (ICC = 0.93 vs 0.91; P > .99) and inter-rater reliability (ICC = 0.80 vs 0.87; P > .99). The plane of movement did not affect inter-rater reliability (P = .11). Significant influences were identified with intrarater reliability (P = .0001) of inexpensive devices, where intrarater reliability decreased (P = .01) in side bending, compared with flexion-extension.

CONCLUSIONS

The use of expensive devices to measure ACROM in adults with nonspecific neck pain does not seem to improve the reliability of the assessment. Side bending had a lower level of intrarater reliability.

Body surface posture evaluation: construction, validation and protocol of the SPGAP system (Posture evaluation rotating platform system)

Background

Several posture evaluation devices have been used to detect deviations of the vertebral column. However it has been observed that the instruments present measurement errors related to the equipment, environment or measurement protocol. This study aimed to build, validate, analyze the reliability and describe a measurement protocol for the use of the Posture Evaluation Rotating Platform System (SPGAP, Brazilian abbreviation).

Methods

The posture evaluation system comprises a Posture Evaluation Rotating Platform, video camera, calibration support and measurement software. Two pilot studies were carried out with 102 elderly individuals (average age 69 years old, SD = ±7.3) to establish a protocol for SPGAP, controlling the measurement errors related to the environment, equipment and the person under evaluation. Content validation was completed with input from judges with expertise in posture measurement. The variation coefficient method was used to validate the measurement by the instrument of an object with known dimensions. Finally, reliability was established using repeated measurements of the known object.

Results

Expert content judges gave the system excellent ratings for content validity (mean 9.4 out of 10; SD 1.13). The measurement of an object with known dimensions indicated excellent validity (all measurement errors <1 %) and test-retest reliability. A total of 26 images were needed to stabilize the system. Participants in the pilot studies indicated that they felt comfortable throughout the assessment. The use of only one image can offer measurements that underestimate or overestimate the reality. To verify the images of objects with known dimensions the values for the width and height were, respectively, CV 0.88 (width) and 2.33 (height), SD 0.22 (width) and 0.35 (height), minimum and maximum values 24.83–25.2 (width) and 14.56 – 15.75 (height). In the analysis of different images (similar) of an individual, greater discrepancies were observed in the values found. The cervical index, for example, presented minimum and maximum values of 15.38 and 37.5, a coefficient of variation of 0.29 and a standard deviation of 6.78.

Conclusions

The SPGAP was shown to be a valid and reliable instrument for the quantitative analysis of body posture with applicability and clinical use, since it managed to reduce several measurement errors, amongst which parallax distortion.

Photographic measurement of head and cervical posture when viewing mobile phone: a pilot study

PURPOSE

With the dramatic growth of mobile phone usage, concerns have been raised with regard to the adverse health effects of mobile phone on spinal posture. The aim of this study was to determine the head and cervical postures by photogrammetry when viewing the mobile phone screen, compared with those in neutral standing posture.

METHODS

A total of 186 subjects (81 females and 105 males) aged from 17 to 31 years old participated in this study. Subjects were instructed to stand neutrally and using mobile phone as in daily life. Using a photographic method, the sagittal head and cervical postures were assessed by head tilt angle, neck tilt angle, forward head shift and gaze angle.

RESULTS

The photographic method showed a high intra-rater and inter-rater reliability in measuring the sagittal posture of cervical spine and gaze angle (ICCs ranged from 0.80 to 0.99). When looking at mobile phone, the head tilt angle significantly increased (from 74.55° to 95.22°, p = 0.000) and the neck angle decreased (from 54.68° to 38.77°, p = 0.000). The forward head posture was also confirmed by the significantly increased head shift (from 10.90 to 13.85 cm, p = 0.000). The posture assumed in mobile phone use was significantly correlated with neutral posture (p < 0.05). Males displayed a more forward head posture than females (p < 0.05). The head tilt angle was positively correlated with the gaze angle (r = 0.616, p = 0.000), while the neck tilt angle was negatively correlated with the gaze angle (r = -0.628, p = 0.000).

CONCLUSIONS

Photogrammetry is a reliable, quantitative method to evaluate the head and cervical posture during mobile phone use. Compared to neutral standing, subjects display a more forward head posture when viewing the mobile phone screen, which is correlated with neutral posture, gaze angle and gender. Future studies will be needed to investigate a dose-response relationship between mobile phone use and assumed posture.

The relationship between sitting posture and seated-related upper quadrant musculoskeletal pain in computing South African adolescents: A prospective study

BACKGROUND

There is evidence that consistent sitting for prolonged periods is associated with upper quadrant musculoskeletal pain (UQMP). It is unclear whether postural alignment is a significant risk factor.

OBJECTIVE AND DESIGN

The aim of the prospective study (2010-2011) was to ascertain if three-dimensional sitting postural angles, measured in a real-life school computer classroom setting, predict seated-related UQMP.

METHOD

Asymptomatic Grade 10 high-school students, aged 15-17 years, undertaking Computer Application Technology, were eligible to participate. Using the 3D Posture Analysis Tool, sitting posture was measured while students used desk-top computers. Posture was reported as five upper quadrant angles (Head flexion, Neck flexion; Craniocervical angle, Trunk flexion and Head lateral bending). The Computer Usage Questionnaire measured seated-related UQMP and hours of computer use. The Beck Depression Inventory and the Multidimensional Anxiety Scale for Children assessed psychosocial factors. Sitting posture, computer use and psychosocial factors were measured at baseline. UQMP was measured at six months and one-year follow-up.

RESULTS

211, 190 and 153 students participated at baseline, six months and one-year follow-up respectively. 34.2% students complained of seated-related UQMP during the follow-up period. Increased head flexion (HF) predicted seated-related UQMP developing over time for a small group of students with pain scores greater than the 90th pain percentile, adjusted for age, gender, BMI, computer use and psychosocial factors (p = 0.003). The pain score increased 0.22 points per 1° increase in HF.

CONCLUSIONS

Classroom ergonomics and postural hygiene should therefore focus on reducing large HF angles among computing adolescents.

The spinal posture of computing adolescents in a real-life setting

Background

It is assumed that good postural alignment is associated with the less likelihood of musculoskeletal pain symptoms. Encouraging good sitting postures have not reported consequent musculoskeletal pain reduction in school-based populations, possibly due to a lack of clear understanding of good posture. Therefore this paper describes the variability of postural angles in a cohort of asymptomatic high-school students whilst working on desk-top computers in a school computer classroom and to report on the relationship between the postural angles and age, gender, height, weight and computer use.

Methods

The baseline data from a 12 month longitudinal study is reported. The study was conducted in South African school computer classrooms. 194 Grade 10 high-school students, from randomly selected high-schools, aged 15–17 years, enrolled in Computer Application Technology for the first time, asymptomatic during the preceding month, and from whom written informed consent were obtained, participated in the study. The 3D Posture Analysis Tool captured five postural angles (head flexion, neck flexion, cranio-cervical angle, trunk flexion and head lateral bend) while the students were working on desk-top computers. Height, weight and computer use were also measured. Individual and combinations of postural angles were analysed.

Results

944 Students were screened for eligibility of which the data of 194 students are reported. Trunk flexion was the most variable angle. Increased neck flexion and the combination of increased head flexion, neck flexion and trunk flexion were significantly associated with increased weight and BMI (p = 0.0001).

Conclusions

High-school students sit with greater ranges of trunk flexion (leaning forward or reclining) when using the classroom computer. Increased weight is significantly associated with increased sagittal plane postural angles.