MRI Compatible Lumbopelvic Movement Measurement System to Validate and Capture Task Performance During Neuroimaging.

Research suggests that structural and functional changes within the brain are associated with chronic low back pain, and these cortical alterations might contribute to impaired sensorimotor control of the trunk and hips in this population. However, linking sensorimotor brain changes with altered movement of the trunk and hips during task-based neuroimaging presents significant challenges. An MRI-safe pressure measurement system was developed to ensure proper task completion during neuroimaging by capturing movement patterns of the trunk (sensors under the lower back) and hips (sensors embedded in the foam roll under the knees). Pressure changes were measured outside of the scanner by digital differential pressure sensors to capture time-series data and analog pressure gauges for real-time determination of task performance occurring within an MRI bore during brain imaging. This study examined the concurrent validity of air pressure changes between the digital and analog sensors. The digital and analog data were compared in 23 participants during the performance of modified bilateral and unilateral right and left hip bridges. Spearman's correlations were calculated for each sensor during the three bridging tasks and showed high positive correlations, indicating that over 87% of pressure change from the analog gauge can be explained by the pressure from the digital sensor. Bland-Altman plots showed no bias and mean differences were under three mmHg. This pressure system improves the rigor of future studies by validating the digital data from the system and increasing the capabilities of capturing lumbopelvic task performance occurring inside the scanner bore.

Trunk postural control during unstable sitting among individuals with and without low back pain: A systematic review with an individual participant data meta-analysis.

INTRODUCTION: Sitting on an unstable surface is a common paradigm to investigate trunk postural control among individuals with low back pain (LBP), by minimizing the influence lower extremities on balance control. Outcomes of many small studies are inconsistent (e.g., some find differences between groups while others do not), potentially due to confounding factors such as age, sex, body mass index [BMI], or clinical presentations. We conducted a systematic review with an individual participant data (IPD) meta-analysis to investigate whether trunk postural control differs between those with and without LBP, and whether the difference between groups is impacted by vision and potential confounding factors. METHODS: We completed this review according to PRISMA-IPD guidelines. The literature was screened (up to 7th September 2023) from five electronic databases: MEDLINE, CINAHL, Embase, Scopus, and Web of Science Core Collection. Outcome measures were extracted that describe unstable seat movements, specifically centre of pressure or seat angle. Our main analyses included: 1) a two-stage IPD meta-analysis to assess the difference between groups and their interaction with age, sex, BMI, and vision on trunk postural control; 2) and a two-stage IPD meta-regression to determine the effects of LBP clinical features (pain intensity, disability, pain catastrophizing, and fear-avoidance beliefs) on trunk postural control. RESULTS: Forty studies (1,821 participants) were included for the descriptive analysis and 24 studies (1,050 participants) were included for the IPD analysis. IPD meta-analyses revealed three main findings: (a) trunk postural control was worse (higher root mean square displacement [RMSdispl], range, and long-term diffusion; lower mean power frequency) among individuals with than without LBP; (b) trunk postural control deteriorated more (higher RMSdispl, short- and long-term diffusion) among individuals with than without LBP when vision was removed; and (c) older age and higher BMI had greater adverse impacts on trunk postural control (higher short-term diffusion; longer time and distance coordinates of the critical point) among individuals with than without LBP. IPD meta-regressions indicated no associations between the limited LBP clinical features that could be considered and trunk postural control. CONCLUSION: Trunk postural control appears to be inferior among individuals with LBP, which was indicated by increased seat movements and some evidence of trunk stiffening. These findings are likely explained by delayed or less accurate corrective responses. SYSTEMATIC REVIEW REGISTRATION: This review has been registered in PROSPERO (registration number: CRD42021124658).

The Seated Trunk Control Test: Investigation of Reliability and Known-Groups Validity Using Individuals Post-Anterior Cruciate Ligament Reconstruction.

CONTEXT: Decreased trunk neuromuscular control is a risk factor for both upper- and lower-extremity injuries, yet there are few reliable and valid clinical tests to identify deficits. OBJECTIVE: The purpose of this study was to determine the reliability and known-groups validity of a novel clinical test, the seated trunk control test (STCT). DESIGN: Cross-sectional reliability and known-groups validity study. SETTING: Laboratory. PARTICIPANTS: 89 unique participants: 34 were 3 months postoperative anterior cruciate ligament reconstruction (ACLR) and 55 healthy controls. METHODS: For the STCT, participants sat on a balance board with their eyes closed for three 30-second trials while investigators counted balance errors. Intraclass correlations (ICCs) were used to assess interrater reliability (N = 20) and test-retest reliability (N = 40). To assess known-groups validity, independent t tests were used to compare STCT errors at 3 months post-ACLR with healthy matched controls (N = 34/group). Area under a receiver operating characteristic curve identified an optimal cutoff for distinguishing between groups. RESULTS: The STCT had perfect interrater reliability (ICC2,3 = 1.00) and good test-retest reliability (ICC3,3 = .79; 95% confidence interval = .61-.89). The ACLR group made significantly more errors on the STCT (mean [SD] = 15.5 [5.4]) than controls (mean [SD] = 8.2 [4.1]; P < .001, Cohen d = 1.52). The STCT's ability to distinguish between groups was excellent (area under a ROC curve = 0.86). A cutoff of 12 errors maximized sensitivity (76%) and specificity (85%). CONCLUSIONS: The STCT is reliable between raters and across days. It also has excellent ability to distinguish between individuals with a recent ACLR and healthy matched controls, which provides initial evidence to suggest that the STCT may be clinically useful for identifying deficits in trunk neuromuscular control.

Test-retest reliability and construct validity of trunk extensor muscle force modulation accuracy.

Low back pain is associated with changes in trunk muscle structure and function and motor control impairments. Voluntary force modulation (FM) of trunk muscles is a unique and under-investigated motor control characteristic. One of the reasons for this paucity of evidence is the lack of exploration and publication on the reliability and validity of trunk FM protocols. The purpose of this study was to determine the within- and between-day test-retest reliability and construct validity for trunk extensor muscle FM. Twenty-nine healthy participants were tested under three FM conditions with different modulation rates. Testing was performed on a custom-built apparatus designed for trunk isometric force testing. FM accuracy relative to a fluctuating target force (20-50%MVF) was quantified using the root mean square error of the participant's generated force relative to the target force. Reliability and precision of measurement were assessed using the Intraclass Correlation Coefficient (ICC), standard error of measurement (SEM), minimal detectable difference (MDD95), and Bland-Altman plots. In a subset of participants, we collected surface electromyography of trunk and hip muscles. We used non-negative matrix factorization (NNMF) to identify the underlying motor control strategies. Within- and between-day test-retest reliability was excellent for FM accuracy across the three conditions (ICC range: 0.865 to 0.979). SEM values ranged 0.9-1.8 Newtons(N) and MDD95 ranged from 2.4-4.9N. Conditions with faster rates of FM had higher ICCs. NNMF analysis revealed two muscle synergies that were consistent across participants and conditions. These synergies demonstrate that the muscles primarily involved in this FM task were indeed the trunk extensor muscles. This protocol can consistently measure FM accuracy within and between testing sessions. Trunk extensor FM, as measured by this protocol, is not specific to any trunk muscle group but is the result of modulation by all the trunk extensor muscles.

Mind-Body Exercise Performed by Physical Therapists for Reducing Pain and Disability in Low Back Pain: A Systematic Review With Meta-analysis.

OBJECTIVE: To assess the effectiveness of mind-body (MB) exercise interventions provided by physical therapists for reducing pain and disability in people with low back pain (LBP). DATA SOURCES: MEDLINE, Embase, CINAHL, and the Cochrane Library were searched for articles published in English between December 2010 and June 2020. STUDY SELECTION: Randomized controlled trials evaluating the effects of Pilates, yoga, and tai chi interventions performed by physical therapists on pain or disability outcomes in adults with musculoskeletal LBP were included. DATA EXTRACTION: Data were extracted by 2 independent reviewers. Quality of evidence and risk of bias were assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework and Cochrane risk of bias tools, respectively. DATA SYNTHESIS: 21,230 exercise trials were identified; 161 progressed to full-text review. Eight trials, 7 reporting on Pilates and 1 reporting on yoga, were included. Short-term outcomes for pain (SMD: -0.93; 95% confidence interval [CI]: -1.65 to -0.021) and disability (SMD: -0.74 95% CI: -1.36 to -0.012) indicated MB exercise was more effective than control intervention. Tests for subgroup differences between studies with exercise vs non-exercise control groups revealed a moderating effect on short-term outcomes where larger effects were observed in studies with non-exercise comparators. Long-term outcomes for pain (SMD: -0.60; 95% CI:-1.43 to 0.23) and disability (SMD: -1.05; 95% CI:-3.51 to 1.41) suggested that MB exercise is not more effective than control interventions for pain or disability. Quality of the evidence ranged from very low to low. CONCLUSIONS: Physical therapist-delivered MB exercise interventions, which overwhelmingly consisted of Pilates, were more effective than control in the short and long-term for pain and in the short-term for disability, with differences in the short-term effects lessened when compared with an active intervention. Pilates interventions delivered by physical therapists represent a viable tool for the clinical management of chronic LBP.

Intrinsic Risk Factors for Noncontact Musculoskeletal Injury in Collegiate Swimmers: A Prospective Cohort Study.

CONTEXT: Shoulder pain is pervasive in swimmers of all ages. However, given the limited number of prospective studies, injury risk factors in swimmers remain uncertain. OBJECTIVE: To determine the extent to which the risk factors of previous injury, poor movement competency, erroneous freestyle swimming technique, and low perceived susceptibility to sport injury were associated with noncontact musculoskeletal injury in collegiate swimmers. DESIGN: Prospective cohort study. SETTING: College natatorium. PATIENTS OR OTHER PARTICIPANTS: Thirty-seven National College Athletic Association Division III swimmers (21 females, 16 males; median age = 19 years [interquartile range = 3 years], height = 175 ± 10 cm; mass = 70.0 ± 10.9 kg). MAIN OUTCOME MEASURE(S): Participants completed preseason questionnaires on their previous injuries and perceived susceptibility to sport injury. At the beginning of the season, they completed the Movement System Screening Tool and the Freestyle Swimming Technique Assessment. Logistic regression was used to calculate odds ratios (ORs) with 95% CIs for the association between each risk factor and injury. RESULTS: Eleven of the 37 participants (29.7%) sustained an injury. Univariate analyses identified 2 risk factors: previous injury (OR = 8.89 [95% CI = 1.78, 44.48]) and crossover hand positions during the freestyle entry phase (OR = 8.50 [95% CI = 1.50, 48.05]). After adjusting for previous injury, we found that a higher perceived percentage chance of injury (1 item from the Perceived Susceptibility to Sport Injury) decreased the injury odds (adjusted OR = 0.11 [95% CI = 0.02, 0.82]). Poor movement competency was not associated with injury (P > .05). CONCLUSIONS: Previous injury, a crossover hand-entry position in freestyle, and a low perceived percentage chance of injury were associated with increased injury odds. Ascertaining injury histories and assessing for crossover positions may help identify swimmers with an elevated injury risk and inform injury-prevention strategies.

Is Real-Time Poolside Assessment of Upper Limb Errors in Front Crawl Swimming Technique Reliable and Equivalent to Video Analysis?

CONTEXT: Swimming technique is widely believed to influence performance, but this relationship has rarely been tested objectively using a real-time poolside assessment. OBJECTIVE: To determine the (1) test-retest reliability, interrater reliability, and criterion validity (live vs video) of real-time poolside assessment of upper limb (UL) errors in front crawl (FC) swimming technique and (2) the relationship between UL errors and FC swimming performance. DESIGN: Cross-sectional reliability, validity, and correlational study. SETTING: Swim team practice at a college natatorium. PARTICIPANTS: Thirty-nine Division III college swimmers (21 women and 18 men, age = 19 [1] y, swimming experience = 11 [3] y). MAIN OUTCOME MEASURES: Seven UL errors in FC swimming technique, many of which involved unnecessary vertical and mediolateral motions, were assessed in real time from outside the pool during swim practice. Test-retest reliability, interrater reliability, and criterion validity were calculated using Cohen kappa (κ) and weighted kappa (κw). Swimming performance was determined by the participants' best FC events relative to the conference records. The correlation between total UL errors and FC swimming performance was assessed with Pearson r. RESULTS: Cohen κ and κw were moderate for the majority of errors, with the following ranges: 0.46 to 0.90 (test-retest), -0.01 to 1.00 (interrater), and 0.36 to 0.66 (criterion validity). There was a significant correlation between total UL errors and FC swimming performance: r(24) = -.59 (P = .001, R2 = .35). CONCLUSIONS: Reliability and validity were moderate for the majority of errors. The fewer UL errors swimmers made while practicing FC, the faster their best FC race times tended to be relative to the conference record. UL errors in FC swimming technique explained 35% of the variance in performance.

Workload and Noncontact Musculoskeletal Injury in Collegiate Swimmers: A Prospective Cohort Study.

CONTEXT: Swimmers are known for experiencing high training loads and a high incidence of overuse injuries, but few researchers have investigated the relationship between the two at the collegiate level. OBJECTIVE: To determine the association between workload and noncontact musculoskeletal injury in collegiate swimmers. DESIGN: Prospective cohort study. SETTING: College natatorium. PATIENTS OR OTHER PARTICIPANTS: A total of 37 National Collegiate Athletic Association Division III swimmers, 26 uninjured (age = 19 years [interquartile range = 3 years], height = 175 ± 11 cm, mass = 70.2 ± 10 kg) and 11 injured (age = 19 years [interquartile range = 3 years], height = 173 ± 9 cm, mass = 69.4 ± 13.5 kg) individuals. MAIN OUTCOME MEASURE(S): Logistic regression using generalized estimating equations was conducted to calculate odds ratios (ORs) with 95% CIs for injury relative to high workloads and high acute:chronic workload ratio (ACWRs). Injury rates for several ranges of workloads and ACWRs were also calculated. RESULTS: A total of 11 participants (29.7%) sustained 12 injuries, with 7 injuries occurring during the participants' winter training trip. Injury was associated with high acute workloads (OR = 27.1; 95% CI = 8.2, 89.8) and high ACWRs (OR = 25.1; 95% CI = 7.7, 81.4) but not high chronic (OR = 2.6; 95% CI = 0.3, 20.0) or overall (OR = 1.00; 95% CI = 0.99, 1.01) workloads. High acute workloads (>37.2 km/wk) and ACWRs (>1.56) increased the injury rate from ≤1% to 15% and 14%, respectively, compared with all lower acute workloads and ACWRs. CONCLUSIONS: Collegiate swimmers tolerated high workloads spread out during the season. However, caution should be used when prescribing high acute workloads and high ACWRs (eg, winter training trip) because of the increased odds of injury.

Task-Based Functional Connectivity and Blood-Oxygen-Level-Dependent Activation During Within-Scanner Performance of Lumbopelvic Motor Tasks: A Functional Magnetic Resonance Imaging Study.

There are a limited number of neuroimaging investigations into motor control of the lumbopelvic musculature. Most investigation examining motor control of the lumbopelvic musculature utilize transcranial magnetic stimulation (TMS) and focus primarily on the motor cortex. This has resulted in a dearth of knowledge as it relates to how other regions of the brain activate during lumbopelvic movement. Additionally, task-based functional connectivity during lumbopelvic movements has not been well elucidated. Therefore, we used functional magnetic resonance imaging (fMRI) to examine brain activation and ROI-to-ROI task-based functional connectivity in 19 healthy individuals (12 female, age 29.8 ± 4.5 years) during the performance of three lumbopelvic movements: modified bilateral bridge, left unilateral bridge, and right unilateral bridge. The whole brain analysis found robust, bilateral activation within the motor regions of the brain during the bilateral bridge task, and contralateral activation of the motor regions during unilateral bridging tasks. Furthermore, the ROI-to-ROI analysis demonstrated significant connectivity of a motor network that included the supplemental motor area, bilateral precentral gyrus, and bilateral cerebellum regardless of the motor task performed. These data suggest that while whole brain activation reveals unique patterns of activation across the three tasks, functional connectivity is very similar. As motor control of the lumbopelvic area is of high interest to those studying low back pain (LBP), this study can provide a comparison for future research into potential connectivity changes that occur in individuals with LBP.

A modified-delphi study establishing consensus in the therapeutic management of posttrauamtic elbow stiffness.

STUDY DESIGN: Web-based modified Delphi study. BACKGROUND: Therapy is widely considered the first choice of treatment for posttraumatic stiffness of the elbow since loss of motion is a common sequela following traumatic elbow injuries. There is high variability in practice patterns for the management of the posttraumtic elbow. PURPOSE: The aim of this study is to identify the current therapeutic management of posttraumatic elbow stiffness using expert consensus. METHODS: This study surveyed experts using a web-based 3 round modified Delphi method. Quantitative data and comments were collected during the first round. Questions with Likert scaling were used to identify consensus (defined as 75% agreement) with each statement and comment boxes enabled open-ended responses to gather expert opinion. Lack of consensus and data from comments guided the second-round of the survey. This process was repeated after Round 2 to develop the Round 3 survey. Consensus was achieved at Round 3 and no further rounds were needed. RESULTS: Round 1 included 34 experts (response rate 20%), not all experts were able to continue through all rounds. Round 2 included 18 experts and Round 3 included 15 experts. Survey items were categorized as follows: examination procedures, therapeutic interventions, orthotic intervention considerations, contributing patient factors, and clinical decisions and rehabilitation challenges. Twenty-five percent of items achieved consensus after Round 1, 30% after Round 2 and 52% after Round 3. Although most participants agreed that orthotic intervention is critical to patient outcomes, there were conflicting thoughts about the orthotic design and wearing schedule. CONCLUSIONS: The findings of this web-based modified Delphi study helped to establish a current body of knowledge using expert consensus to guide practice and identify specific questions that can be studied in future clinical studies on posttraumatic elbow stiffness.

Patients with low back pain use stiffening strategy to compensate for movement control during active prone hip rotation: A cross-sectional study.

BACKGROUND: New motor adaptation to pain theory suggests that patients with low back pain (LBP) use the lumbopelvic stiffening strategy by redistribution of within and between muscle activities to protect painful structure. This could result in an altered postural control of the lumbopelvic region during active prone hip rotation (PHR). OBJECTIVE: To investigate coordination and timing of lumbopelvic and hip movements, and smoothness of the lumbopelvic control during PHR between participants with and without LBP. METHODS: Eight participants with LBP and eight participants without LBP were recruited. The electromagnetic tracking system was used to record kinematic data during PHR. Cross-correlation between hip rotation and lumbopelvic movement in the transverse plane was calculated. Correlation at zero time-lag, time-lag, correlation at time-lag, and maximal lumbopelvic motion were derived. Frequency of movement disruption was identified. An independent t-test was used in conjunction with the effect size and 95% minimal detectable difference (MDD95) to determine the difference in kinematic parameters. RESULTS: Participants with LBP demonstrated a significant delay (exceeding MDD95) in lumbopelvic motion while nonsignificant frequency of disrupted motion on the painful side PHR demonstrated a trend with a large effect size that exceeded MDD95. There were trends with moderate to large effect sizes and differences exceeding MDD95 in delay of lumbopelvic motion with greater movement disruption on the nonpainful side in participants with LBP. CONCLUSION: Participants with LBP used a lumbopelvic stiffening strategy for postural control to protect painful structures; however, the stiffening might complicate efforts to smoothly control lumbopelvic movement.

Scaling of Joint Motion and Muscle Activation for 3-Dimensional Control of Reach Extent.

This study investigated the scaling of upper arm kinematics, joint motion, and muscle activation for three-dimensional (3D) reaches to targets of increasing distance. Fifteen participants completed 108 total reaches to targets placed 7, 14, and 21 cm across midline. Peak velocity, acceleration, and time to peak velocity scaled to both target and movement distance. Shoulder and elbow excursion scaled to target distance and were highly coordinated. Anterior deltoid activation scaled to both target and movement distance in the early and late phases of reach control. Biceps and triceps activation scaled to movement distance primarily in the late phase. Scaling of these outcome variables provides a model for understanding the control of reach distance in a 3D environment.

Interventions for the Management of Acute and Chronic Low Back Pain: Revision 2021.

Low back pain (LBP) remains a musculoskeletal condition with an adverse societal impact. Globally, LBP is highly prevalent and a leading cause of disability. This is an update to the 2012 Academy of Orthopaedic Physical Therapy (AOPT), formerly the Orthopaedic Section of the American Physical Therapy Association (APTA), clinical practice guideline (CPG) for LBP. The overall objective of this update was to provide recommendations on interventions delivered by physical therapists or studied in care settings that included physical therapy providers. It also focused on synthesizing new evidence, with the purpose of making recommendations for specific nonpharmacologic treatments. J Orthop Sports Phys Ther 2021;51(11):CPG1-CPG60. doi:10.2519/jospt.2021.0304.

Assessing sensorimotor control of the lumbopelvic-hip region using task-based functional MRI.

Recent brain imaging studies have suggested that cortical remodeling within sensorimotor regions are associated with persistent low back pain and may be a driving mechanism for the impaired neuromuscular control associated with this condition. This paper outlines a new approach for investigating cortical sensorimotor integration during the performance of small-amplitude lumbopelvic movements with functional MRI. Fourteen healthy right-handed participants were instructed in the lumbopelvic movement tasks performed during fMRI acquisition. Surface electromyography (EMG) collected on 8 lumbopelvic and thigh muscles captured organized patterns of muscle activation during the movement tasks. fMRI data were collected on 10 of 14 participants. Sensorimotor cortical activation across the tasks was identified using a whole brain analysis and further explored with regional analyses of key components of the cortical sensorimotor network. Head motion had low correlation to the tasks (r = -0.101 to 0.004) and head translation averaged 0.98 (0.59 mm) before motion correction. Patterns of activation of the key lumbopelvic and thigh musculature (average amplitude normalized 2-17%) were significantly different across tasks (P > 0.001). Neuroimaging demonstrated activation in key sensorimotor cortical regions that were consistent with motor planning and sensory feedback needed for performing the different tasks. This approach captures the specificity of lumbopelvic sensorimotor control using goal-based tasks (e.g., "lift your hip" vs. "contract your lumbar multifidus to 20% of maximum") performed within the confines of the scanner. Specific patterns of sensorimotor cortex activation appear to capture differences between bilateral and unilateral tasks during voluntary control of multisegmental movement in the lumbopelvic region.NEW & NOTEWORTHY We demonstrated the feasibility of using task-based functional magnetic resonance imaging (fMRI) protocols for acquiring the blood oxygen level-dependent (BOLD) response of key sensorimotor cortex regions during voluntary lumbopelvic movements. Our approach activated lumbopelvic muscles during small-amplitude movements while participants were lying supine in the scanner. Our data supports these tasks can be done with limited head motion and low correlation of head motion to the task. The approach provides opportunities for assessing the role of brain changes in persistent low back pain.

Comparison of core neuromuscular control and lower extremity postural stability in athletes with and without shoulder injuries.

BACKGROUND: The kinetic chain theory is widely used as a rationale for the inclusion of core stability training in athletes. Core stability (muscle capacity and neuromuscular control) impairments may result in less than optimal performance and abnormal force dissipation to the shoulder complex that could lead to shoulder injuries. However, a paucity of literature exists to support this relationship, and no previous studies have investigated the relationship between isolated core neuromuscular control and shoulder injuries. Additionally, lower extremity postural stability has been associated with athletic function and may also be associated with shoulder injuries. The purpose of this study was to compare biomechanical measures of isolated core neuromuscular control and lower extremity postural stability between athletes with and without non-traumatic shoulder injuries. METHODS: Eighty athletes (55 males, age: 21.2 ± 3.3 years, 40 with a current shoulder injury) completed biomechanical measures of isolated core neuromuscular control and lower extremity postural stability. Athletes were matched by age, gender, body mass index, and sport type. MANOVAs were used to assess differences between measures of core neuromuscular control and lower extremity postural stability between groups. FINDINGS: There were no statistically significant differences between athletes with and without shoulder injuries for the static core neuromuscular control measures, F(4,75) = 0.45, P = 0.78, η2 = 0.02; dynamic core neuromuscular control measures, F(4,75) = 0.81, P = 0.52, η2 = 0.04; or lower extremity postural stability measures, F(8,61) = 0.85, P = 0.56, η2 = 0.10. INTERPRETATION: Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, athletes with current non-traumatic shoulder injuries may not present with impairments in core neuromuscular control or lower extremity postural stability.

Comprehensive movement system screening tool (MSST) for athletes: Development and measurement properties.

OBJECTIVES: Non-traumatic extremity injuries are particularly common in sports, representing a significant economic, academic, and psychosocial burden on athletes. Proposed musculoskeletal risk factors for increased injury and decreased performance in athletes include movement pattern inefficiency, decreased regional stability, decreased mobility, and asymmetrical movement. The Movement System Screening Tool (MSST) is a comprehensive screening tool designed to assess these factors. Thus, the purpose of this study was to describe the development and determine the content and construct validity and inter-rater reliability of the MSST. METHODS: A modified Delphi panel of experts determined content validity. 80 athletes (40 with and 40 without a current non-traumatic shoulder injury) completed 21 clinical tests, with exploratory factor analysis and known group analysis performed to determine construct validity. Two independent raters were used to establish individual item and composite score inter-rater reliability. RESULTS: Exploratory factor analysis identified three of the four apriori constructs over 7 factors (14 tests), representing 63% of the variance. Known group analysis revealed a significantly lower composite score in athletes with vs. without a current non-traumatic shoulder injury (56.9±5.8 vs. 62.7±4.5, respectively). A preliminary cut score of 62 was chosen with sensitivity of 85% and specificity of 44%. Composite score inter-rater reliability was excellent ICC (2,1)=0.94, 95% CI (0.91, 0.96) and item reliability ranged from κ=.57 to 1.00. CONCLUSIONS: The MSST possesses constructs representative of injury risk and measurement properties acceptable for use in clinical settings. Comprehensive screens with construct validity and known measurement error are needed not only to identify athletes at risk of injury, but also provide an instrument that can be used in studies that seek to validate training approaches proposed to change movement impairment and injury risk in athletes.

Characterizing and Understanding the Low Back Pain Experience Among Persons with Lower Limb Loss.

OBJECTIVE: This study preliminarily characterizes and compares the impact of lower limb loss and development of chronic low back pain (cLBP) on psychosocial factors, as well as the relationship between these factors and low back pain-related functional disability. DESIGN: Cross-sectional study. METHODS: Participants were adults, active duty or retired military, with traumatic lower limb loss with and without chronic low back pain. Psychosocial factors and low back pain-related functional disability were measured using common clinical self-report questionnaires. The presence of psychosocial factors was compared between those with and without cLBP using multivariate analysis of covariance (P < 0.05), and correlations determined relationships between psychosocial factors and cLBP-related functional disability. RESULTS: There were no statistically significant differences among psychosocial factors between those with vs without cLBP (F(4, 13) = 0.81, P = 0.54, η2= 0.19). Employment status (ρ = 0.43, P = 0.02), anxiety (ρ = 0.45, P = 0.04), and kinesiophobia (ρ = 0.47, P = 0.04) were moderately associated with low back pain-related disability. CONCLUSIONS: Psychological (i.e., anxiety) and social (i.e., employment status) factors may influence how persons with traumatic lower limb loss respond to self-reported measures of low back pain-related disability. The findings suggest that the Modified Oswestry Disability Index identifies cLBP-related functional disability in the context of lower limb loss. These results support the interdependence among biological, psychological, and social factors, which should be collectively considered during the development of rehabilitative strategies to treat secondary musculoskeletal conditions within this population.

Chronic low back pain influences trunk neuromuscular control during unstable sitting among persons with lower-limb loss.

BACKGROUND: Persons with unilateral lower-limb loss are at increased risk for developing chronic low back pain. Aberrant trunk and pelvis motor behavior secondary to lower-limb loss potentially alters trunk postural control and increases demands on the trunk musculature for stability. However, it is unclear whether trunk postural control is associated with the presence or chronicity of low back pain within this population. RESEARCH QUESTION: Is there a potential role of impaired trunk postural control among persons with lower limb loss and chronic low back pain? METHODS: Two groups of males with unilateral lower-limb loss (n = 18 with chronic low back pain; n = 13 without pain) performed an unstable sitting task. Trunk postural control was characterized using traditional and non-linear measures derived from center-of-pressure time series, as well as trunk kinematics and the ratio of lumbar to thoracic erector spinae muscle activations. RESULTS: Traditional and non-linear center-of-pressure measures and trunk muscle activation ratios were similar between groups, while participants with chronic low back pain demonstrated greater trunk motion and reduced local dynamic stability. SIGNIFICANCE: Our results suggest that persons with both lower-limb loss and chronic low back pain exhibit impaired trunk postural control compared to those with limb loss but without pain. Aberrant trunk motor behavior may be a response to altered functional requirements of walking with a prosthesis. An inability to adequately control the trunk could lead to spinal instability and pain in the presence of repetitive exposure to aberrant motor behavior of these proximal structures during everyday activities.

Individuals With and Without Low Back Pain Use Different Motor Control Strategies to Achieve Spinal Stiffness During the Prone Instability Test.

BACKGROUND: The prone instability test is used to identify individuals with low back pain (LBP) who would benefit from trunk stabilization exercises. Although activity from muscles during the leg-raising portion of the prone instability test theoretically enhances spinal stiffness and reduces pain, evidence for this is lacking. OBJECTIVES: To compare and contrast (1) pain and stiffness changes between prone instability testing positions, and (2) muscle activation patterns during the prone instability test leg raise in individuals with and without LBP. METHODS: Participants with (n = 10) and without (n = 10) LBP participated in this laboratory case-control study. Spinal stiffness was measured using a beam-bending model and 3-D kinematic data. Stiffness changes were compared across the test positions and between groups. Surface electromyographic data were collected on trunk and limb musculature. Principal-component analysis was used to extract muscle synergies. RESULTS: Spinal stiffness increased across testing positions in all participants (P<.05). Participants with LBP experienced reduced pain during the test (P<.001). No between-group difference was found in spinal stiffness during leg raising during the test (P>.05). Participants without LBP used 3 muscle synergies during the leg raise and participants with LBP used 2 muscle synergies. CONCLUSION: Spinal stiffness increased in all participants; however, participants without LBP demonstrated a muscle synergy pattern where each synergy was associated with a distinct function of the prone instability test. Participants with LBP used a more global stabilization pattern, which may reflect a maladaptive method of enhancing spinal stability. J Orthop Sports Phys Ther 2019;49(12):899-907. Epub 3 Aug 2019. doi:10.2519/jospt.2019.8577.

Lumbar Multifidus and Erector Spinae Muscle Synergies in Patients with Nonspecific Low Back Pain During Prone Hip Extension: A Cross-sectional Study.

BACKGROUND: Prone hip extension is used to clinically assess movement control in patients with nonspecific low back pain (LBP). Excessive lumbopelvic movements and altered muscle activation patterns are common in patients with nonspecific LBP. However, no evidence exists regarding lumbar multifidus and lumbar erector spinae muscle synergy patterns in patients with nonspecific LBP during this clinical test. OBJECTIVE: To determine the difference in lumbopelvic motion and change in muscle synergy between patients with nonspecific LBP and healthy individuals. DESIGN: A cross-sectional study design. SETTING: University physical therapy clinic and laboratory. PARTICIPANTS: Seven patients with nonspecific LBP (age [mean ± SD] 29 ± 5 years, 43% female, body mass index [BMI] of 25 ± 2 kg/m2 , Numeric Pain Rating Scale 6 ± 2; Oswestry Disability Index 20% ± 8%) and seven age-, sex-, and BMI-matched healthy individuals (mean age 28 ± 5 years, 43% female, BMI of 22 ± 2 kg/m2 ) were recruited. METHODS: Each participant performed six repetitions of prone hip extension on each side; kinematic and electromyographic data were collected simultaneously. MAIN OUTCOME MEASUREMENTS: Kinematic data were used to represent lumbopelvic motion, whereas electromyography (EMG) data were used to represent muscle activity. A paired t-test was used to determine the difference in lumbopelvic motion. Principal component analysis and two-way repeated-measures analysis of variance were used to extract muscle synergies and identify differences in muscle synergy patterns between and within groups. RESULTS: Results demonstrated no significant group difference (P > .05) in amount of lumbopelvic motion. However, healthy individuals synergistically activate lumbar multifidus and lumbar erector spinae with 81.0% variance accounted for (VAF). Patients with nonspecific LBP had an altered synergy with independent activation of lumbar multifidus on the painful side with 32.0% VAF and the lumbar multifidus on the nonpainful side, and both lumbar erector spinae with 52.2% VAF synergistically activated. CONCLUSIONS: These findings suggest that clinicians should focus on muscle activation patterns rather than the amount of lumbopelvic motion during clinical observation of prone hip extension. LEVEL OF EVIDENCE: Level III.