Test-retest reliability of sit-to-stand and stand-to-sit analysis in people with and without chronic non-specific low back pain

3D motion capture data into a kinematic composite score for assessing musculoskeletal impairments

Biomechanical analysis is essential for understanding and monitoring musculoskeletal impairments, with implications for clinical diagnostics and research. Current clinical methods provide isolated joint measures or qualitative observations, failing to capture motion complexity. While 3D biomechanical testing is comprehensive, its application is hindered by data volume, making it challenging to derive clinically relevant conclusions. Approaches to distill motion often neglect time-series data or are dependent on population size. To address these gaps, this study introduces the Kinematic Composite Score (K-Score), a metric that distills high-dimensional motion while preserving individual variability. The objective of this research is to outline the methodology of the K-Score algorithm, highlight its strengths, limitations, and applications. We conducted a comparative study of the K-Score Algorithm against (1) the conventional isolated kinematic measures, and (2) traditional Principal Component Analysis. The analysis was conducted with a cohort of chronic low back pain (LBP) patients, who exhibit tremendous movement heterogeneity. The K-Score outperformed traditional isolated metrics in differentiating overall motion of LBP patients from healthy controls (K-Score: controls = 94.16 ± 2.64, LBP = 85.82 ± 7.73, p < 0.001). The K-Score also demonstrated significant differences in overall motion between male and female participants, where females with LBP demonstrated higher scores than males (p < 0.001). Importantly, the K-Score was not sensitive to BMI (p = 0.49), age (p = 0.14), height (p = 0.11), or sample size. In conclusion, the K-Score addresses key limitations of traditional approaches by encapsulating full-body, time-series data within a single score that is adaptable across motion capture systems and activities, making it a powerful tool for clinical biomechanics research.

Reliability and validity of surface EMG assessments combined with isometric muscle strength testing in patients with abdominal rectus diastasis and asymptomatic controls

PURPOSE

Patients with abdominal rectus diastasis (ARD) may have muscular functional impairments, but clinics lack appropriate objective assessment tools. The aim was to establish the relative and absolute reliability, and convergent validity, of muscular activity using Surface Electromyography (SEMG) during isometric abdominal muscle strength testing in patients with ARD and controls without ARD.

METHODS

Twenty-six patients with ARD were matched for age, sex and BMI with controls without ARD. Participants were tested twice during isometric muscular contractions using SEMG located on six abdominal sites. Mean amplitude, fatigue, and recruitment order were analyzed. Relative reliability was evaluated with Intraclass Correlation Coefficients (ICC), while absolute reliability was estimated by calculating the Standard Error of Measurement and Minimal Detectable Change. Convergent validity was addressed in relation to participant characteristics, functional ability, and symptoms.

RESULTS

Mean SEMG amplitude for all abdominal wall muscle contractions showed moderate to excellent relative test-retest reliability, with ICC values ranging from 0.46 to 0.97. In contrast, fatigue and recruitment order displayed poor to moderate relative reliability in both groups. Absolute reliability measures were generally high. A moderate to high convergent validity (ARD: rho-value 0.41-0.70; Controls: rho-value 0.41-0.75) was observed for mean amplitude in relation to a functional sit-to-stand test, abdominal circumference, BMI, back pain, and quality-of-life.

CONCLUSIONS

The results of applying SEMG during isometric abdominal muscle support practicing the method in clinics, although additional development is needed with further standardization and more functional testing. Furthermore, the method demonstrates construct validity in patients with ARD and in age- and sex-matched controls.

Pelvic and Lower Limb Kinematics in Individuals With Chronic Low Back Pain During Sit-to-Stand Function: A Cross-Sectional Study

OBJECTIVES

The aim of this study was to investigate the 3-dimensional movement kinematics of pelvic and lower limb joints in CLBP subjects, compared to healthy individuals, utilizing a functional data analysis (FDA) approach.

METHODS

In this study, a 7-camera Qualisys motion capture system was employed to record the kinematics of the pelvic, hip, knee, and ankle joints in 20 patients with low back pain (LBP) and 20 control subjects on both sides during the sit-to-stand motion. An FDA statistical approach was utilized to compare the data collected over time between the 2 groups. The STS task was divided into two distinct phases: the prelift off phase (pre-Lo) and the postlift off phase (post-Lo).

RESULTS

During the "pre-Lo phase" of the STS motion, our statistical analysis revealed that the only significant difference between the two groups was a decreased medial rotation (P = .00) in the hip joint position of LBP patients on their dominant side, in comparison to healthy subjects. As for the "post-Lo phase," the LBP group exhibited a more anterior pelvic tilt position (P = .00) and increased pelvic counterclockwise rotation (P = .03) in the sagittal and transverse planes when compared to the control group. Regarding hip joints, the LBP group demonstrated a more flexed position (indicative of reduced extension) on both the dominant (P = .00) and nondominant (P = .00) sides, coupled with diminished abduction (P = .04) and internal rotation (P = .03) of the hip on the dominant side. In relation to the knee and ankle joints, the results indicated a more adducted knee position (P = .00) and decreased ankle joint flexion (P = .02) on the dominant side in CLBP subjects when compared to the healthy group during the STS motion.

CONCLUSION

Our findings indicate that patients with CLBP exhibited distinct kinematic patterns in the pelvic and lower limb joints during the STS motion. These kinematic alterations primarily manifest in the joints of the dominant limb, with most of the differences observed during the second phase (postlift off phase) of the motion. It appears that these changes in pelvic and lower limb joint kinematics should be taken into account when planning future rehabilitation programs for CLBP patients engaged in this task.

The effect of low back pain on spine kinematics: A systematic review and meta-analysis

BACKGROUND

Although impairments in dorso-lumbar spine mobility have been previously reported in patients with low back pain, its exact mechanism is not yet clear. Therefore, the purpose of this systematic review and meta-analysis is to investigate and compare spinal kinematics between subjects with and without low back pain and identify appropriate tools to evaluate it.

METHODS

The PubMed, Scopus and Web of Science databases were searched for relevant literature. The search strategy was mainly focused on studies investigating lumbar kinematics in subjects with and without low back pain during clinical functional tests, gait, sports and daily functional activities. Papers were selected if at least one of these outputs was reported: lumbar range of motion, lumbar velocity, lumbar acceleration and deceleration, lordosis angle or lumbar excursion.

FINDINGS

Among 804 papers, 48 met the review eligibility criteria and 29 were eligible to perform a meta-analysis. Lumbar range of motion was the primary outcome measured. A statistically significant limitation of the lumbar mobility was found in low back pain group in all planes, and in the frontal and transverse planes for thoracic range of motion, but there is no significant limitation for pelvic mobility. The amount of limitation was found to be more important in the lumbar sagittal plane and during challenging functional activities in comparison with simple activities.

INTERPRETATION

The findings of this review provide insight into the impact of low back pain on spinal kinematics during specific movements, contributing to our understanding of this relationship and suggesting potential clinical implications.

Measurement properties of 72 movement biomarkers aiming to discriminate non‑specific chronic low back pain patients from an asymptomatic population

The identification of relevant and valid biomarkers to distinguish patients with non-specific chronic low back pain (NSCLBP) from an asymptomatic population in terms of musculoskeletal factors could contribute to patient follow-up and to evaluate therapeutic strategies. Several parameters related to movement impairments have been proposed in the literature in that respect. However, most of them were assessed in only one study, and only 8% were evaluated in terms of reliability, validity and interpretability. The aim of this study was to consolidate the current knowledge about movement biomarkers to discriminate NSCLBP patients from an asymptomatic population. For that, an experimental protocol was established to assess the reliability, validity and interpretability of a set of 72 movement biomarkers on 30 asymptomatic participants and 30 NSCLBP patients. Correlations between the biomarkers and common patient reported outcome measures were also analysed. Four biomarkers reached at least a good level in reliability (ICC ≥ 0.75) and validity (significant difference between asymptomatic participants and NSCLBP patients, p ≤ 0.01) domains and could thus be possibly considered as valuable biomarkers: maximal lumbar sagittal angle, lumbar sagittal angle range of motion, mean lumbar sagittal angular velocity, and maximal upper lumbar sagittal angle during trunk sagittal bending. These four biomarkers demonstrated typically larger values in asymptomatic participants than in NSCLBP patients. They are in general weakly correlated with patient reported outcome measures, arguing for a potential interest in including related musculoskeletal factors in the establishment of a valuable diagnosis and in guiding treatment response.

Between-day reliability of trunk orientation measured with smartphone sensors during sit-to-stand in asymptomatic individuals

BACKGROUND

Trunk kinematics during sit-to-stand is often impaired in individuals with musculoskeletal disorders. Trunk kinematics is commonly assessed in laboratories using motion capture; however, this equipment is often not available outside research centers. Smartphones are widely available and may be a suitable alternative to assess trunk orientation during sit-to-stand remotely.

OBJECTIVES

We investigated whether trunk orientation in the sagittal plane during sit-to-stand can be measured reliably between days when collected remotely using smartphones.

DESIGN

Cross-sectional study.

METHOD

Forty-three asymptomatic participants performed 15 sit-to-stand movements in two separate sessions remotely over videoconferencing. Trunk orientation was measured using each participant's smartphone. Absolute peak trunk orientation in the sagittal plane was extracted during standing, sitting, stand up and sit down. Relative trunk orientation was calculated as the difference between sitting and stand up, or sitting and sit down. Reliability was assessed using Intraclass Correlation Coefficient (ICC_2,k), Standard Error of Measurement (SEM) and Minimal Detectable change (MDC). Between day bias and between-gender differences were assessed using T tests.

RESULTS

All measures showed good reliability (ICC_2,k > 0.80; SEM < 5.6°; MDC < 13.6°) and no between-day bias (p > 0.31). Relative measures were more consistent (ICC_2,k > 0.88; SEM < 3.6°; MDC < 9.9°). No between-gender differences were observed for relative orientation (p > 0.75).

CONCLUSIONS

Sagittal trunk orientation during sitting, standing, and sit-to-stand can be measured reliably when asymptomatic individuals use their own smartphones supervised over videoconferencing. These findings support the use of smartphone sensors for assessing how trunk orientation changes over time, which may assist physiotherapists assess movement patterns of individuals with musculoskeletal disorders remotely.

Biomechanical factors associated with non-specific low back pain in adults: A systematic review

Low back pain (LBP) can result in increased direct medical and non-medical costs to patients, employers, and health care providers. This systematic review aimed to provide a better understanding of the biomechanical factors associated with chronic non-specific LBP in adults. SCOPUS, ScienceDirect, MEDLINE, and Web of Science databases were searched. In total, 26 studies were included and significant differences were noted between healthy controls and LBP patients in various motion. Biomechanical factors among adults with non-specific LBP were altered and differed as compared to healthy controls in various motion might be to compensate the pain during those motions. This review highlighted the biomechanical differences across those with non-specific LBP and healthy adults. Both groups showed a similar level of pain during functional tasks but LBP patients suffered from a moderate level of disability. Future studies should not rely on questionnaire-based pain scale only. The biomechanical factors summarized in this review can be used to diagnose non-specific LBP accurately, and as modifiable targets for exercise-based intervention.

Comparison of Kinematic Movement Patterns Between 2 Subgroups of Females With Low Back Pain and Healthy Women During Sit-to-Stand and Stand-to-Sit

The purpose of study was to compare the kinematic patterns of the thoracic, lumbar, and pelvis segments and hip joints between 2 low back pain subgroups and healthy women during sit-to-stand and stand-to-sit. Kinematic data of 44 healthy women and 2 subgroups of females with low back pain in 2 subgroups of movement system impairment model (rotation-extension [Rot.Ext] and rotation-flexion [Rot.Flex]) were recorded. Participants performed sit-to-stand and stand-to-sit at a preferred speed. Each task was divided into a pre buttock lifted off/on (pre-BOff/n) phase and a post-BOff/n phase. The Rot.Ext subgroup showed greater range of motion in the thoracic during pre-BOff phase of sit-to-stand (P < .001) and pre-BOn phase of stand-to-sit (P = .01) compared to the other 2 groups. The Rot.Flex subgroup displayed limited left hip joint excursion during sit-to-stand pre-BOff (P = .04) and stand-to-sit post-BOn phases (P = .02). The Rot.Flex subgroup showed greater pelvis tilt excursion during sit-to-stand post-BOff (P = .04) and stand-to-sit pre-BOn (P = .01) and post-BOn phases (P = .01). In subgroups of women with chronic low back pain, there were kinematic changes in adjacent body segments/joints of lumbar spine during sit-to-stand and stand-to-sit tasks.

Machine Learning Identifies Chronic Low Back Pain Patients from an Instrumented Trunk Bending and Return Test

Nowadays, the better assessment of low back pain (LBP) is an important challenge, as it is the leading musculoskeletal condition worldwide in terms of years of disability. The objective of this study was to evaluate the relevance of various machine learning (ML) algorithms and Sample Entropy (SampEn), which assesses the complexity of motion variability in identifying the condition of low back pain. Twenty chronic low-back pain (CLBP) patients and 20 healthy non-LBP participants performed 1-min repetitive bending (flexion) and return (extension) trunk movements. Analysis was performed using the time series recorded by three inertial sensors attached to the participants. It was found that SampEn was significantly lower in CLBP patients, indicating a loss of movement complexity due to LBP. Gaussian Naive Bayes ML proved to be the best of the various tested algorithms, achieving 79% accuracy in identifying CLBP patients. Angular velocity of flexion movement was the most discriminative feature in the ML analysis. This study demonstrated that: supervised ML and a complexity assessment of trunk movement variability are useful in the identification of CLBP condition, and that simple kinematic indicators are sensitive to this condition. Therefore, ML could be progressively adopted by clinicians in the assessment of CLBP patients.

Symptomatic individuals with Lumbar Disc Degeneration use different anticipatory and compensatory kinematic strategies to asymptomatic controls in response to postural perturbation

BACKGROUND

Lumbar Disc Degeneration (LDD) is associated with recurrent low back pain (LBP) (symptomatic). However, in some instances of LDD, people do not experience LBP (asymptomatic).

RESEARCH QUESTION

As a step towards understanding why some people with LDD experience LBP and others do not, the primary aim of this study was to examine differences in anticipatory (APA) and compensatory postural adjustments (CPA), between symptomatic LDD patients (LDD pain) and asymptomatic LDD controls (LDD no pain) during postural perturbation. The secondary aim was to determine simultaneous differences in mental health, disability and quality of life status.

METHODS

3 T MRI was used to acquire T2 weighted images (L1-S1) from LDD no pain (n = 34) and LDD pain groups (n = 34). In this observational study, responses to predicted and unpredicted forward perturbations were examined using three dimensional motion capture. A Mann Whitney U test was conducted to examine group differences in sagittal spine and lower limb kinematics (integrated angular displacements during four established APA and CPA time intervals), anxiety, depression, disability and quality of life.

RESULTS

The LDD pain group exhibited lower hip and knee displacements (p = 0.049-0.040) than the LDD no pain group during predicted and unpredicted perturbation. The LDD pain group also exhibited higher compensatory lumbar displacement than the LDD no pain group (p = 0.040-0.005) in the predicted condition but there was no difference observed in the unpredicted condition. The LDD pain group experienced higher levels of depression, anxiety and disability (p < 0.0001) and lower quality of life (p = 0.0001) than LDD controls.

SIGNIFICANCE

Symptomatic LDD patients are different from LDD controls; they exhibit different kinematic strategies, levels of disability, anxiety, depression and quality of life. Effective care may benefit from evaluating and targeting these differences.

Kinematic analysis of the human body during sit-to-stand in healthy young adults

Sit-to-stand (STS) motion is one of the most important and energy-consuming basic motions in everyday life. Kinematic analysis provides information regarding what strategy or motion pattern is used by the healthy people, and through which, we can understand and obtain the law of the STS motion. The objective of this article is to study the law of STS motion through the experiment to determine a suitable description of STS motion in healthy adults, so as to provide a starting point and bases for future design and control of STS assistive devices.Thirty healthy adult subjects participated in this study and carried out STS motion experiment of standing up naturally. The STS motions were recorded using a high-definition camera. The experimentally collected kinematic data and a link segment model of the human body were used to obtain the coordinates of joints and to calculate the coordinates, velocity, and momentum of center of gravity; the postures of human body during STS are also obtained. The relationship between human body parameters and motion parameters is analyzed by using Pearson correlation method.The STS motion is divided into 4 phases; the phases are differentiated in terms of STS motion characteristics and postures, and momentum of center of gravity of human body. The main factors determining the differences in STS motion among individuals are horizontal distance between hip joint and ankle joint, lower leg length, thigh length, and the length of the transition period. The horizontal distance between hip joint and ankle joint is positively correlated with the duration from motion begin to trunk stops flexing forward (P = .021 < .05), but not so with the duration from motion begin to the end of phase 2 (P = .15 > .05).The results suggest that when designing the sit-to-stand assistive devices, one should pay attention to the whole-body posture control in STS motion, such as the posture guidance of trunk and lower leg, and should carry out specific training according to different STS phases. Sit-to-stand assistive devices should provide the same horizontal distance between hip joint and ankle joint for different individuals during the STS motion. Transition period should be properly controlled, and the degree of freedom of the lower leg should not be limited.

Trunk kinematics and muscle activation patterns during stand-to-sit movement and the relationship with postural stability in aging

BACKGROUND

Stand-to-sit (StandTS) movement is an important functional activity that can be challenging for older adults due to age-related changes in neuromotor control. Although trunk flexion, eccentric contraction of the rectus femoris (RF), and coordination of RF and biceps femoris (BF) muscles are important to the StandTS task, the effects of aging on these and related outcomes are not well studied.

RESEARCH QUESTION

What are the age-related differences in trunk flexion, lower extremity muscle activation patterns, and postural stability during a StandTS task and what is the relationship between these variables?

METHODS

Ten younger and ten older healthy adults performed three StandTS trials at self-selected speeds. Outcomes included peak amplitude, peak timing, burst duration, and onset latency of electromyography (EMG) activity of the RF and BF muscles, trunk flexion angle and angular velocity, whole body center of mass (CoM) displacement, center of pressure (CoP) velocity, and ground reaction force (GRF).

RESULTS

There were no age-related differences in weight-bearing symmetry, StandTS and trunk flexion angular velocity, or BF activity. In both groups, EMG peak timing of RF was preceded by BF. Compared to younger adults, older adults demonstrated shorter RF EMG burst duration, reduced trunk flexion, and reduced stability as indicated by the longer duration in which CoM was maintained beyond the posterior limit of base of support (BoS), greater mean anterior-posterior CoP velocity and larger standard deviation of CoM vertical acceleration during StandTS with smaller vertical GRF immediately prior to StandTS termination. Trunk flexion angle and RF EMG burst duration correlated with stability as measured by the duration in which the CoM stayed within the BoS.

SIGNIFICANCE

Decreased trunk flexion and impaired eccentric control of the RF are associated with StandTS instability in aging and suggest the importance of including StandTS training as a part of a comprehensive balance intervention.

A systematic review of movement and muscular activity biomarkers to discriminate non-specific chronic low back pain patients from an asymptomatic population

The identification of relevant and valid biomarkers to distinguish patients with non-specific chronic low back pain (NSCLBP) from an asymptomatic population in terms of musculoskeletal factors could contribute to patient follow-up and to evaluate therapeutic strategies. Several parameters related to movement and/or muscular activity impairments have been proposed in the literature in that respect. In this article, we propose a systematic and comprehensive review of these parameters (i.e. potential biomarkers) and related measurement properties. This systematic review (PROSPERO registration number: CRD42020144877) was conducted in Medline, Embase, and Web of Knowledge databases until July 2019. In the included studies, all movements or muscular activity parameters having demonstrated at least a moderate level of construct validity were defined as biomarkers, and their measurement properties were assessed. In total, 92 studies were included. This allowed to identify 121 movement and 150 muscular activity biomarkers. An extensive measurement properties assessment was found in 31 movement and 14 muscular activity biomarkers. On the whole, these biomarkers support the primary biomechanical concepts proposed for low back pain. However, a consensus concerning a robust and standardised biomechanical approach to assess low back pain is needed.

Lumbar Spine Kinematics in Asymptomatic People When Changing Body Position From Sitting to Standing

OBJECTIVE

The purpose of this study was to assess the lumbar spine kinematics in 3 movement axes in asymptomatic individuals in the sit-to-stand (STS) movement performed in a habitual, flexion, or extension manner.

METHODS

There were 30 participants (16 women, 14 men), aged 23 to 37 years. Each participant performed an STS test. We registered the total time of the STS movement and the maximum acceleration of the lumbar spine in the vertical, anteroposterior, and mediolateral axes. The examination of the movement pattern was performed with the use of a BTS G-sensor device.

RESULTS

The highest movement dynamics in the lumbar spine were observed during the STS performed in a habitual manner in the 3 axes (P < .01). The lowest movement dynamics ere associated with the extension STS pattern. The flexion pattern differed from the habitual one in total performance time in both groups (P < .01). There were no significant differences in kinematic lumbar spine between sexes.

CONCLUSION

The kinematics of the STS movement for asymptomatic individuals were characterized by significant variability in the maximum acceleration in the 3 axes. The highest movement dynamics were observed during the STS performed in a habitual manner, and the lowest dynamics with the extension pattern of STS.

The test-retest reliability and concurrent validity of the five times sit to stand test and step test in older adults with total hip arthroplasty

PURPOSE

The aim of the study was to determine the test-retest reliability and concurrent validity of the five times sit to stand test (FTST) and step test (ST) in older adults with total hip arthroplasty (THA).

METHODS

A cross-sectional and prospective study was carried out with 32 unilateral total hip arthroplasty patients. FTST, ST, and Timed Up & Go Test were evaluated at the first evaluation session. The test-retest reliability was evaluated by performing two repetitions of the FTST and ST. Besides, the functional status of the patients was evaluated with the Harris Hip Score (HHS). The test-retest reliability of the FTST and ST were assessed by the intraclass correlation coefficient (ICC). In the concurrent validity analysis, the Pearson correlation coefficient was analyzed. In addition, the standard error of measurement (SEM₉₅) and minimal detectable change (MDC₉₅) values of the FTST and ST were also calculated.

RESULTS

The mean age of the participants was 75.4 ± 10.3 years. The ICC score of FTST, ST (right) and ST (left) were 0.987, 0.908 and 0.846, respectively. SEM₉₅ and MDC₉₅ values of the FTST were 1.05 and 2.91, respectively. FTST was correlated with both the HHS and TUG (r₁ = -0.522, r₂ = 0.730, p < 0.01). SEM₉₅ and MDC₉₅ values of the ST (right) were 0.37 and 1.02, respectively. SEM₉₅ and MDC₉₅ values of the ST (left) were 0.55 and 1.52, respectively. Also, ST (right) was only correlated with TUG (r = -0.654, p < 0.01). ST (right) were correlated with both the HHS and TUG (r₁ = 0.503, r₂ = -0.806, p < 0.01). The degree of correlations was strong.

CONCLUSION

The FTST and ST are valid and reliable performance tests in older adults with primary unilateral THA.

The Effectiveness of Trunk Stabilization Exercise Combined with Vibration for Adolescent Patients with Nonspecific Low Back Pain

There are many adolescent patients complaining of low back pain, but research on it is lacking. The purpose of this study was to investigate the effects of trunk stabilization exercise combined with vibration on the pain, proprioception, and kinematics of the lumbar spine (LS) during sit to stand (STS) in adolescent patients with nonspecific low back pain (LBP). Fifty LBP patients were recruited and were randomly divided into two groups: Vibration group (n = 25) and placebo group (n = 25). All participants underwent 36-sessions of training consisting of six exercises. The Vibration group provided vibration stimulation during exercise, but the placebo group did not. The Numeric Pain Rating Scale (NPRS) and digital dual inclinometer were used to measure pain intensity and proprioception. The kinematics of the lumbar spine during STS were measured by motion capture system. After training, the pain and proprioception in the vibration group improved significantly greater than the placebo group (p < 0.05). The mobility of LS (maximum range of motion, angular velocity, lumbar to hip movement ratios) and lumbar-hip coordination during STS in the vibration group were significantly improved compared to the placebo group (p < 0.05). Thus, trunk stabilization exercise combined with vibration may be used to improve the pain, proprioception, and kinematic of the lumbar spine during sit to stand in adolescent patients with LBP.

Sit-To-Stand Movement Evaluated Using an Inertial Measurement Unit Embedded in Smart Glasses-A Validation Study

Wearable sensors have recently been used to evaluate biomechanical parameters of everyday movements, but few have been located at the head level. This study investigated the relative and absolute reliability (intra- and inter-session) and concurrent validity of an inertial measurement unit (IMU) embedded in smart eyeglasses during sit-to-stand (STS) movements for the measurement of maximal acceleration of the head. Reliability and concurrent validity were investigated in nineteen young and healthy participants by comparing the acceleration values of the glasses’ IMU to an optoelectronic system. Sit-to-stand movements were performed in laboratory conditions using standardized tests. Participants wore the smart glasses and completed two testing sessions with STS movements performed at two speeds (slow and comfortable) under two different conditions (with and without a cervical collar). Both the vertical and anteroposterior acceleration values were collected and analyzed. The use of the cervical collar did not significantly influence the results obtained. The relative reliability intra- and inter-session was good to excellent (i.e., intraclass correlation coefficients were between 0.78 and 0.91) and excellent absolute reliability (i.e., standard error of the measurement lower than 10% of the average test or retest value) was observed for the glasses, especially for the vertical axis. Whatever the testing sessions in all conditions, significant correlations (p < 0.001) were found for the acceleration values recorded either in the vertical axis and in the anteroposterior axis between the glasses and the optoelectronic system. Concurrent validity between the glasses and the optoelectronic system was observed. Our observations indicate that the IMU embedded in smart glasses is accurate to measure vertical acceleration during STS movements. Further studies should investigate the use of these smart glasses to assess the STS movement in unstandardized settings (i.e., clinical and/or home) and to report vertical acceleration values in an elderly population of fallers and non-fallers.

Effect of Chronic Low Back Pain on Lumbar Spine Lordosis During Sit-to-Stand and Stand-to-Sit

OBJECTIVE

This study aimed to evaluate lumbar lordosis during sit-to-stand (STS) and stand-to-sit (SIT) in individuals with and without chronic nonspecific low back pain (CNLBP). The second objective was to investigate sex-related differences in lumbar lordosis.

METHODS

Twenty-six patients with CNLBP and 26 controls were recruited. Controls were matched with cases using a frequency matching method. Reflective markers were placed over the spinous process of T₁₂, L₃, S₂, and the anterior and posterior superior iliac spines. The participants were instructed to stand up at a self-selected pace and maintain their normal upright standing posture for 3 seconds, and then sit down. Kinematic data were recorded at a sampling frequency of 100 Hz using a motion capture system. Lumbar lordosis angle was calculated from the intersection between the line joining T₁₂ and L₃, and the line joining L₃ to S₂.

RESULTS

Lumbar lordosis was decreased in patients with CNLBP during STS and SIT compared with the asymptomatic group (mean difference = 2.68°-9.32°; P ≤ .005). Furthermore, no differences were seen in lumbar lordosis at starting position between CNLBP and asymptomatic groups during STS and SIT (mean difference = 2.68°-3.75°; P ≥ .099). Interestingly, the magnitude of the effect size suggested that the difference in lumbar lordosis values between female and male participants was relatively large (Cohen's d = -1.81 to 0.20).

CONCLUSION

Decreased lumbar lordosis in patients with CNLBP during STS and SIT could be considered as an important point during rehabilitation. Moreover, the present study showed that there is a sex-related difference among women and men in lumbar lordosis during STS and SIT tasks.

Psychometric Properties of the iHandy Level Smartphone Application for Measuring Lumbar Spine Range of Motion and Lordosis: A Systematic Review of the Literature

CONTEXT

Advent of smartphones has brought a wide range of clinical measurement applications (apps) within the reach of most clinicians. The vast majority of smartphones have numerous built-in sensors such as magnetometers, accelerometers, and gyroscopes that make the phone capable of measuring joint range of motion (ROM) and detecting joint positions. The iHandy Level app is a free app which has a visual display alike with the digital inclinometer in regard to numeric size.

OBJECTIVE

The purpose of this systematic review was to evaluate available evidence in the literature to assess the psychometric properties (ie, reliability and validity) of the iHandy Level app in measuring lumbar spine ROM and lordosis.

METHODS

PubMed/MEDLINE, Scopus, Ovid, Google Scholar, and ScienceDirect were searched from inception to September 2018 for single-group repeated-measures studies reporting outcomes of lumbar spine ROM or lordosis in adult individuals without symptoms of low back pain (LBP) or patients with LBP. The quality of each included study was assessed using the Quality Appraisal of Reliability Studies checklist.

RESULTS

A total of 4 studies with 273 participants were included. Two studies focused on measuring active lumbar spine ROM, and 2 studies evaluated lumbar spine lordosis. Three studies included asymptomatic subjects, and one study recruited patients with LBP. The results showed that the iHandy Level app has sufficient psychometric properties for measuring standing thoraco-lumbo-sacral flexion, extension, lateral flexion, isolated lumbar spine flexion ROM, and lumbar spine lordosis in asymptomatic subjects. One study reported poor concurrent validity with a bubble inclinometer (r = .19-.53), poor intrarater reliability (intraclass correlation coefficient = .19-.39), and poor to good interrater reliability (intraclass correlation coefficient = .24-.72) for the measurement of active lumbar spine ROM using the iHandy Level app in patients with LBP.

CONCLUSIONS

This review provided a valuable summary of the research to date examining the psychometric properties of the iHandy Level app for measuring lumbar spine ROM and lordosis.

Does manual therapy affect functional and biomechanical outcomes of a sit-to-stand task in a population with low back pain? A preliminary analysis

Introduction

Manual therapy (MT) hypothetically affects discrepant neuromuscular control and movement observed in populations with low back pain (LBP). Previous studies have demonstrated the limited influence of MT on movement, predominately during range of motion (ROM) testing. It remains unclear if MT affects neuromuscular control in mobility-based activities of daily living (ADLs). The sit-to-stand (STS) task represents a commonly-performed ADL that is used in a variety of clinical settings to assess functional and biomechanical performance.

Objective

To determine whether MT affects functional performance and biomechanical performance during a STS task in a population with LBP.

Methods

Kinematic data were recorded from the pelvis and thorax of participants with LBP, using an optoelectronic motion capture system as they performed a STS task before and after MT from November 2011 to August 2014. MT for each participant consisted of two high-velocity low-amplitude spinal manipulations, as well as two grade IV mobilizations of the lumbar spine and pelvis targeted toward the third lumbar vertebra and sacroiliac joint in a side-lying position; the order of these treatments was randomized. Pelvis and thorax kinematic data were used to derive the time-varying lumbar angle in the sagittal plane for each STS trial. The difference between the maximum and minimum lumbar angles during the STS trial determined the sagittal ROM that was used as the biomechanical outcome. Time to complete each STS trial was used as a functional measure of performance. Pre-MT and post-MT values for the lumbar sagittal ROM and time to completion were statistically analysed using paired samples t-tests.

Results

Data were obtained from 40 participants with 35 useful datasets (NRS = 3.3 ± 1.2; 32.4 ± 9.8 years; 16 females, 19 males). After MT, lumbar sagittal ROM increased by 2.7 ± 5.5 degrees (p = 0.007). Time to complete the STS test decreased by 0.4 ± 0.4 s (p < 0.001).

Discussion

These findings provide preliminary evidence that MT might influence the biomechanical and functional performance of an STS task in populations with LBP. The MT intervention in this study involved a combination of spinal manipulations and mobilizations. Future work will expand upon these data as a basis for targeted investigations on the effects of either spinal manipulation and mobilization on neuromuscular control and movement in populations with LBP.

Changes in the macroscopic morphology of hip muscles in low back pain

Low back pain is a major health issue affecting the lumbopelvic muscles. Morphological changes in hip muscles, such as alterations in the muscle cross-sectional area and muscle volume, may occur in patients with low back pain. This systematic review was conducted to investigate whether patients with low back pain have macroscopic changes in their hip muscle morphology compared with asymptomatic, healthy individuals, based on current evidence. The electronic databases of PubMed/Medline, Ovid, Scopus, Embase^® , and Google Scholar were searched from the inception to August 31, 2018. We only included full texts of original studies regarding macroscopic morphological alterations, including atrophy and fat infiltration, in hip muscles of patients with low back pain compared with asymptomatic controls. The quality of the included studies was determined using an assessment tool based on the Newcastle-Ottawa Scale. The scale was modified for the purposes of this study. Sixteen comparative observational studies were found eligible to be included in this review. Eleven were classified as high quality and four as moderate quality. The morphological changes in the psoas major, gluteus maximus, gluteus medius, gluteus minimus, and piriformis muscles were assessed in the primary studies. All selected studies were considered B level of evidence studies. The strength of conclusions for the psoas major, gluteal, and piriformis muscles was moderate. The results revealed that there is substantial controversy about the morphological changes in hip muscles in patients with low back pain; however, the majority of high-quality studies concluded that atrophy of hip muscles is evident in patients with low back pain. The psoas major muscle was the most commonly investigated hip muscle for morphological changes. Major methodological limitations of the included studies were identified and discussed. The present systematic review does not include a formal meta-analysis because of very significant differences in the primary studies in terms of study populations and methodologies. Finally, in clinical practice, it is recommended that physical therapists develop exercise programs to improve hip muscle function in patients with low back pain.

Stand-to-sit kinematic changes during pregnancy correspond with reduced sagittal plane hip motion

BACKGROUND

The stand-to-sit motion has been linked to falls during pregnancy. It is also used in the clinical evaluation of functional performance. The physical and physiological changes during pregnancy may necessitate a change in stand-to-sit kinematic performance. Therefore, this study was conducted to evaluate the longitudinal changes to stand-to-sit kinematics during pregnancy.

METHODS

Fifteen pregnant women were tested in 4-week intervals from 16 weeks to 36 weeks gestational age. They performed a 60-second trial of semi-continuous stand-to-sit motion. Sagittal plane motions at the ankle, knee, spine, and shoulders were measured. Additionally, three-dimensional hip motion was measured. Discrete variables (e.g. range of motion) and joint coordinations (through vector coding) were analyzed over time through a linear mixed model analysis.

FINDINGS

The results indicate a shift away from sagittal hip motion throughout pregnancy. Hip range of motion and standing angle changed in favor of spine motion. Joint coordination shifted from hip dominant to spine- and shoulder-dominate coordination just before the start of sitting motion. Hip-knee joint coordination just before seat contact shifted from hip to a knee-dominant motion during pregnancy.

INTERPRETATION

Discrete variable changes in the entire stand-to-sit motion seem to be driven by initial standing posture related to an increase in gestational lordosis. Likewise, standing joint coordination shift to upper body motion can be attributed to gestational lordosis limiting functional ability around the hip. The shift in motion away from the hip may provide insight into why both fall rates and low back pain rates increase during stand-to-sit during pregnancy.

The reliability and concurrent validity of a new iPhone® application for measuring active lumbar spine flexion and extension range of motion in patients with low back pain

Objective: To investigate the reliability and validity of an iPhone® application (iHandy® Level) for measuring active lumbar flexion-extension range of motion (ROM) in chronic nonspecific low back pain (CNLBP) patients. Methods: Fifteen CNLBP patients were recruited. The participants stood in a relaxed position and the T12-L1 and S1-S2 spinal levels were identified through palpation and were marked on the skin. Two blinded examiners used a gravity-based inclinometer and the application in order to measure ROM. The instruments were lined up appropriately and the participants were asked to perform maximum lumbar flexion following by maximum extension. First, each examiner placed the instruments over the T12-L1 level and then over the S1-S2 level during the movements. In order to calculate flexion-extension ROM, the measurement which was obtained from T12-L1 was subtracted from S1-S2. Intraclass correlation coefficient (ICC) models (3, k) and (2, k) were used in order to determine the intrarater and inter-rater reliability, respectively. The Spearman's correlation coefficients (r_s ) and Bland-Altman plots were used in order to examine the validity. Results: Fair-to-excellent intrarater (ICC = 0.39-0.89) and moderate-to-good inter-rater reliability (ICC = 0.55-0.77) were observed using the inclinometer. Moreover, poor-to-good intrarater (ICC = 0.30-70) and inter-rater (ICC = 0.13-0.70) reliability were found with the application. The Spearman's correlation coefficients demonstrated low-to-moderate associations between the measures of the two instruments (r_s ≥ 0.22). The Bland-Altman plots indicated that there was a significant difference between the instruments for measuring flexion ROM. The difference was not significant for measuring extension ROM. Conclusion: The iHandy® Level application does not have sufficient validity for measuring active lumbar flexion ROM in CNLBP patients.

Movement variability in adults with low back pain during sit-to-stand-to-sit

BACKGROUND

Differences in movement variability may be related to a guarded response to pain or a less robust movement pattern, indicating a potential dysfunction in motor control. The study objective was to compare patterns of lumbo-pelvic coordinative variability, during repeated sit-to-stand-to-sit, in individuals with low back pain and healthy adults.

METHODS

Participants were adults with low back pain (n = 16) and healthy controls (n = 21). Kinematics for the T12-L3, L3-S1, and hip segments were measured using electromagnetic motion capture during 10 sit-to-stand-to-sit trials. Continuous relative phase analysis using the Hilbert transform method determined coordination and variability of the Hip-L3S1, and L3S1-T12L3 segments, deconstructed into 4 periods (start/up/down/end). T-tests compared coordination and variability of the full task between groups, and a mixed ANOVA compared the effects of group and period for the two segments.

FINDINGS

Across the full task, the low back pain group demonstrated more variable (mean difference = -6.95, 95% CI = -12.3 to -1.59) and greater out-of-phase behavior (mean difference = -22.6, 95% CI = -39.1 to -6.03) in the LHip-L3S1 segment. Group-period interaction effects revealed greater variability in the start period (mean difference = -0.325, 95% CI = -0.493 to -0.156) and more out-of-phase behavior in the start (mean difference = -0.350, 95% CI = -0.549 to -0.150) and end (mean difference = -0.354, 95% CI = -0.602 to -0.105) periods for the LHip-L3S1 segment.

INTERPRETATION

Excessive variability may relate to reports of poor spinal proprioception in low back pain; however, based on our sample characteristics (low pain and disability) and lack of symptoms during the task, classifying our findings as dysfunctional may not be fully warranted.