Investigating force-time characteristics of prone thoracic SMT and self-reported patient outcome measures: a feasibility study.

BACKGROUND: Spinal manipulative therapy (SMT) is commonly used to treat musculoskeletal conditions, including thoracic spine pain. Applying patient-specific force-time characteristics are believed to be important to improve SMT's effectiveness. Investigating SMT as part of a multimodal approach is fundamental to account for the complexity of chiropractic clinical practice. Therefore, pragmatic investigations balancing minimal disruptions to the clinical encounter at the same time as ensuring a robust data quality with rigorous protocols are needed. Consequently, preliminary studies are required to assess the study protocol, quality of data recorded and the sustainability of such investigation. Therefore, this study examined the feasibility of investigating SMT force-time characteristics and clinical outcome measures in a clinical setting. METHODS: In this mixed-methods study, providers recorded thoracic SMT force-time characteristics delivered to patients with thoracic spinal pain during regular clinical encounters. Self-reported clinical outcomes of pain, stiffness, comfort during the SMT (using an electronic visual analogue scale), and global rating of change scale were measured before and after each SMT application. Feasibility was quantitatively assessed for participant recruitment, data collection and data quality. Qualitative data assessed participants' perceptions on the impact of data collection on patient management and clinical flow. RESULTS: Twelve providers (58% female, 27.3 ± 5.0 years old) and twelve patients (58% female, 37.2 ± 14.0 years old) participated in the study. Enrolment rate was greater than 40%, data collection rate was 49% and erroneous data was less than 5%. Participant acceptance was good with both providers and patients reporting positive experience with the study. CONCLUSIONS: Recording SMT force-time characteristics and self-reported clinical outcome measures during a clinical encounter may be feasible with specific modification to the current protocol. The study protocol did not negatively impact patient management. Specific strategies to optimize the data collection protocol for the development of a large clinical database are being developed.

A Kinematic Comparison Between Sit-to-Stand Movements and Individual Cycles of the 5-Cycle Sit-to-Stand Test.

OBJECTIVE: The 5-cycle sit-to-stand (5XSTS) test is frequently used to test physical function for different clinical populations, with time to complete as the measured outcome. This study evaluated the similarity of kinematics between a single cycle of the STS movement and individual cycles of the 5XSTS test. METHODS: Lower extremity, pelvis, and thorax kinematic data were monitored as 20 participants (aged 18-40) completed 5 trials of the STS movement and 1 trial of the 5XSTS test. Correlations and root mean squared differences assessed the temporal and spatial similarities in kinematic patterns of sagittal plane joint angles at the ankles, knees, hips, and spine between single cycles of the STS movement and individual cycles of the 5XSTS test. Peak joint angles were obtained along with discrete angles at the start, seat off, and end of the movement. RESULTS: Temporal and spatial similarity of kinematics for the ankles and hips were reduced over cycles 2 to 5 of the 5XSTS. Increased hip flexion was observed at the start of cycles 2 to 5 of the 5XSTS test. Increased knee and hip flexion were observed at the end of cycles 1 to 4 of the 5XSTS test. CONCLUSIONS: Temporal patterns of sagittal plane joint angles captured in the first cycle of the 5XSTS represented those adopted for an isolated STS movement. Different initial conditions for cycles 2 to 5 of the 5XSTS 58 may have reduced temporal and spatial similarity of sagittal plane joint angles of the ankles and hips.

Characterization of thoracic spinal manipulation and mobilization forces in older adults.

BACKGROUND: Spinal mobilization and spinal manipulation are common interventions used by manual therapists to treat musculoskeletal conditions in older adults. Their force-time characteristics applied to older adults' thoracic spine are important considerations for effectiveness and safety but remain unknown. This study aimed to describe the force-time characteristics of posterior-to-anterior spinal mobilization and manipulation delivered to older adults' thoracic spine. METHODS: Twenty-one older adults (≥65 years) with no thoracic pain received posterior-to-anterior thoracic spinal mobilization and/or manipulation with the force characteristics a chiropractor deemed appropriate. Six-degree-of-freedom load cells and an instrumented treatment table recorded the force characteristics of both interventions at the clinician-participant and participant-table interfaces, respectively. Preload force, total peak force, time to peak and loading rate were analyzed descriptively. FINDINGS: Based on data from 18 adults (56% female; average: 70 years old), mean resultant spinal mobilization forces at the clinician-participant interface were: 220 ± 51 N during preload, 323 ± 67 N total peak force, and 312 ± 38 ms time to peak. At the participant-table interface, mobilization forces were 201 ± 50 N during preload, 296 ± 63 N total peak force, and 308 ± 44 ms time to peak. Mean resultant spinal manipulation forces at the clinician-participant interface were: 260 ± 41 N during preload, 470 ± 46 N total peak force, and 165 ± 28 ms time to peak. At the participant table interface, spinal manipulation forces were 236 ± 47 N during preload, 463 ± 57 N total peak force, and 169 ± 28 ms time to peak. INTERPRETATION: Results suggest older adults experience unique, but comparable force-time characteristics during spinal mobilization and manipulation delivered to their thoracic spine compared to the ones delivered to younger adults described in the literature.

Effect of Drop-Piece High-Velocity, Low-Amplitude Manipulation to the Midfoot of Asymptomatic Adult Sprinters on Performance During a Unilateral Horizontal Drop-Jump Test: A Feasibility Investigation.

OBJECTIVE: The purpose of this study was to investigate the feasibility of measuring the immediate effects of drop-piece high-velocity, low-amplitude (DP-HVLA) manipulation to the midfoot region on jump distance in competitive adult sprinters during a standardized unilateral horizontal drop-jump (U-HDJ) test. METHODS: Seven asymptomatic competitive adult sprinters (4 women) were recruited for this study. Testing was conducted on the dominant leg. Participants completed a 10-minute self-selected warm-up, followed by a 6-jump familiarization period with the U-HDJ test. All participants completed 3 U-HDJ trials before and after receiving DP-HVLA chiropractic manipulation to the joints of the midfoot assessed as being hypomobile by a licensed sports chiropractor. The primary outcome of the U-HDJ test was horizontal displacement, measured using an optoelectronic motion-capture system. Mean, SD, and 95% confidence intervals were determined for the posttreatment change in jump distance. A single-sample t test with α = 0.05 assessed the posttreatment change in jumping distance. RESULTS: We were able to measure immediate effects. The preliminary findings showed an increase in jump distance after DP-HVLA manipulation to the midfoot region (mean = 0.06 m, SD = 0.05 m; P = .014; 95% confidence interval, 0.02-0.11; effect size = 1.30). CONCLUSION: This study demonstrates that it was feasible to measure immediate improvement in performance after DP-HVLA chiropractic manipulation in a clinical assessment with correlation to sprinting performance in a population of elite sprinters. As this was a feasibility study, the small sample size, overlapping confidence intervals, and specific niche population limit the extrapolation of these findings.

Reported 1-year prevalence of occupational musculoskeletal disorders in Ontario chiropractors.

BACKGROUND: Chiropractors are a particular subset of health care professionals that reportedly suffer occupational musculoskeletal disorders (MSDs), yet they have received minimal attention to date regarding mitigating risks of occupational injury. Our study determined the prevalence of occupationally-related MSDs in the preceding year, their bodily distribution, severity, and practice-related changes in practicing chiropractors in the province of Ontario. METHODS: We conducted a cross-sectional survey of chiropractors who were members of the Ontario Chiropractic Association (OCA) from January to March 2019. A three-part online survey was developed to ask chiropractors about specific details of MSDs they experienced in the past year and any practice-related changes they made as a result. Responses from participants provided both quantitative and qualitative data. Prevalence estimates were derived for quantitative data. Qualitative data were stratified by themes that were further divided into categories and subcategories. Demographic variables of the respondents and OCA membership were compared to determine representativeness. RESULTS: From the 432 responses (11.8% response rate), 59.1% reported experiencing an occupationally-related MSD in the past year. Survey respondents were demographically representative of the OCA membership. MSDs were most commonly reported for the lower back (38.3%), wrists/hands (38.1%) and neck (37.4%). Positioning/performing manipulation was the most common occupational activity for MSD of the upper extremity (53.1%) and lower back (34.8%). Chiropractors largely reported their MSDs did not prevent them from doing their normal work (77.4%), despite the fact that 43.2% reported experiencing their MSDs for more than 30 days in the previous year. Common reported work modifications were grouped under themes of practice and physical changes. Practice changes included reducing patient volume, hiring personnel and scheduling. Physical changes included using different office equipment, selecting different techniques requiring lower force and altering their hand contacts or body position when treating patients. CONCLUSIONS: One-year prevalence of occupational MSDs from this study are comparable to previously reported estimates in chiropractors. These data suggest that chiropractors continue with their regular workload despite their MSDs, thereby increasing their chances of presenteeism. Chiropractors changing technique or technique parameters due to their MSDs provides direction for future research to reduce exposure to occupational MSD risk factors.

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.

Force transmission between thoracic and cervical segments of the spine during prone-lying high-velocity low-amplitude spinal manipulation: A proof of principle for the concept of regional interdependence.

BACKGROUND: Regional interdependence is conceptually based on observations that applying manual therapy to a remote anatomical region has an effect in the area of the patient's primary complaint. The current model for regional interdependence depends on force transmissibility within the body. This investigation sought to determine transmissibility between forces applied to the thoracic spine during prone-lying high-velocity low-amplitude spinal manipulative therapy and the cervical spine. METHODS: A chiropractic treatment table was modified to allow (or disallow) translation of the headrest in the caudal-cephalad direction when unlocked (or locked). Prone-lying high-velocity low-amplitude spinal manipulative therapy was applied to the thoracic region of 9 healthy participants with the headrest in both configurations. Head and thorax kinematics and kinetics were measured at interfaces between participant and the external environment, which included the clinician's hands. Compressive forces at the cervicothoracic junction and angular kinematics of the cervical spine were derived. Ratios between the clinician-applied forces (input) and the cervical compressive force (output) were also determined. FINDINGS: The cervical spine extended during all high-velocity low-amplitude spinal manipulative therapy trials. Force input-to-output ratios exceeded 1 for high-velocity low-amplitude spinal manipulative therapy trials performed with the headrest in the locked configuration, which was greater than ratios for the unlocked configuration. INTERPRETATION: Forces imparted to thoracic spine during high-velocity low-amplitude spinal manipulative therapy were transmitted to the cervical spine, which provided a precursor for the regional interdependence model for manual therapy. Friction between the participant's face and the treatment table's head rest likely amplified cervical compressive forces.

A descriptive analysis of shoulder muscle activities during individual stages of the Turkish Get-Up exercise.

The Turkish Get-Up (TGU) is a complex and multi-planar exercise; the performer begins in a supine lying position, progresses toward upright standing through a series of 7 stages while holding a mass overhead in one hand, and returns to the original supine lying position through a reversal of the same 7 stages. A descriptive analysis of shoulder muscle activity during the TGU may provide insight toward its use in training and rehabilitation contexts. Our objectives were to: (1) describe the activity patterns from a subset of muscles that span the glenohumeral joint during individual stages of the TGU, and (2) interpret these patterns through comparisons between left- and right-side muscles, and between the up and down phases of the TGU. Twelve individuals with at least one-year experience performing the TGU were included in this study. Surface electromyographic (EMG) recordings were bilaterally obtained from 8 glenohumeral muscle groups while participants performed ten trials of the TGU with a kettlebell in their right hand. Instants representing the start and end of each TGU stage were identified from a synchronized video for each trial, and EMG activities for each muscle were integrated over the duration of each stage. Average integrated EMG and within-participant coefficients of variation were calculated. Overall, the greatest muscular demand occurred during the second (press to elbow support) and fifth (leg sweep) stages. Activities from muscles on the ipsilateral side to the kettlebell (right-side) were greater during stages when the contralateral upper limb did not contribute to supporting the body; however, contralateral (left-side) muscles were invoked during stages when the non-kettlebell-bearing forearm or hand contributed to supporting the body. The results suggest the importance of training both phases of the TGU to gain the most benefit from the exercise and highlights the asymmetric nature of the exercise, which may be particularly relevant for athletes engaged in activities with rotational demands.

Procedure Selection and Patient Positioning Influence Spine Kinematics During High-Velocity, Low-Amplitude Spinal Manipulation Applied to the Low Back.

OBJECTIVES: This investigation compared indirect 3-dimensional angular kinematics (position, velocity, and acceleration) of the lumbar spine for 2 different high-velocity, low-amplitude (HVLA) spinal manipulation procedures (lumbar spinous pull or push), and altered initial patient lower limb posture. METHODS: Twenty-four participants underwent 6 HVLA procedures directed toward the presumed L4 vertebra, reflecting each combination of 2 variants of a spinal manipulation application technique (spinous pull and push) and 3 initial hip flexion angles (0°, 45°, and 90°) applied using a right lateral recumbent patient position. All contact forces and moments between the patient and the external environment, as well as 3-dimensional kinematics of the patient's pelvis and thorax, were recorded. Lumbar spine angular positions, velocities, and accelerations were analyzed within the preload and impulse stages of each HVLA trial. RESULTS: Lumbar spine left axial rotation was greater for the pull HVLA. The pull HVLA also generated a greater maximum (leftward) and lower minimum (rightward) axial rotation velocity and deceleration and greater leftward and rightward lateral bend velocities, acceleration, and deceleration components. Not flexing the hip produced the greatest amount of extension, as well as the lowest axial rotation and maximum axial rotation acceleration during the impulse. CONCLUSIONS: This investigation provides basic kinematic information for clinicians to understand the similarities and differences between 2 HVLA side-lying manipulations in the lumbar spine. Use of these findings and novel technology can drive future research initiatives that can both affect clinical decision making and influence teaching environments surrounding spinal manipulative therapy skill acquisition.

Development of a Linked Segment Model to Derive Patient Low Back Reaction Forces and Moments During High-Velocity Low-Amplitude Spinal Manipulation.

OBJECTIVE: The purpose of this paper is to present the experimental setup, the development, and implementation of a new scalable model capable of efficiently handling data required to determine low back kinetics during high-velocity low-amplitude spinal manipulation (HVLA-SM). METHODS: The model was implemented in Visual3D software. All contact forces and moments between the patient and the external environment (2 clinician hand contact forces, 1 contact force between the patient and the treatment table), the patient upper body kinematics, and inertial properties were used as input. Spine kinetics and kinematics were determined from a single HVLA-SM applied to one healthy participant in a right side-lying posture to demonstrate the model's utility. The net applied force was used to separate the spine kinetic and kinematic time-series data from the HVLA-SM into preload as well as early and late impulse phases. RESULTS: Time-series data obtained from the HVLA-SM procedure showed that the participant's spine underwent left axial rotation, combined with extension, and a reduction in left lateral bending during the procedure. All components of the reaction force, as well as the axial twist and flexion/extension reaction moments demonstrated a sinusoidal pattern during the early and late impulse phases. During the early impulse phase, the participant's spine experienced a leftward axial twisting moment of 37.0 Nm followed by a rightward moment of -45.8 Nm. The lateral bend reaction moment exhibited a bimodal pattern during the early and late impulse phases. CONCLUSION: This model was the first attempt to directly measure all contact forces acting on the participant/patient's upper body, and integrate them with spine kinematic data to determine patient low back reaction forces and moments during HVLA-SM in a side-lying posture. Advantages of this model include the brevity of data collection (<1 hour), and adaptability for different patient anthropometries and clinician-patient contacts.

Comparison of 2 methods of measuring spine angular kinematics during dynamic flexion movements: skin-mounted markers compared with markers affixed to rigid bodies.

OBJECTIVE: The purpose of this study was to compare the spine flexion angle time histories computed with the 2 described techniques (dot product [DP] and a modified joint coordinate system [JCS] approaches) that used vector algebra and used skin-mounted markers to the spine flexion angles derived using local coordinate systems constructed from rigid bodies affixed to the pelvis and thorax during spine flexion movements. METHODS: Discrepancies between the simplified marker setup and a criterion standard (CS) method for measuring spine kinematics were quantified. Sixteen participants performed full forward spine flexion. Three-dimensional kinematic data were obtained from markers affixed bilaterally over the greater trochanters, iliac crests, and 10th ribs. Time varying spine flexion angles were derived from the 3-, and 2-dimensional marker data using a DP and a modified JCS approach. Criterion standard spine kinematics were obtained from clusters of markers adhered to 2 rigid fins that were affixed over the pelvis and trunk. The DP and JCS methods were compared with the CS by computing root mean squared differences and correlations during the spine flexion trials. Descriptive measurements of missing kinematic data were also obtained. RESULTS: On average, root mean squared differences were 30.1% lower for the JCS method of deriving spine flexion angles. Correlations were also higher for the JCS method by 2.5%, compared with the DP method. CONCLUSION: The findings suggest that the adapted JCS method is superior to the DP method for deriving spine flexion angles. This is especially true when only 2-dimensional coordinate data are available.