Brent S. Russell

The purpose of this study was to examine characteristics of cervical axial rotation and other motion components during cervical spine manipulation. Eleven doctors of chiropractic (DCs), 10 chiropractic students with patient experience, and 16 inexperienced students from our institution each performed 4 thrusts on a mannequin. The thrust measured is an essential component of chiropractic cervical spine manipulation, also known as a chiropractic adjustment. The mannequin was designed for chiropractic education and outfitted with inertial measurement units for motion capture. Data were analyzed in Excel for rotation, lateral bending, and flexion-extension at thrust onsets and peaks. Differences between groups were analyzed in R (R Foundation) using Kruskal-Wallis tests, followed by Dunn tests for pairwise comparisons. Mean rotation for DCs was 19.3° at thrust onset and 33.9° at peak; mean peak lateral bending and cervical extension were 32.0° and 10.4°, respectively. On average, 14.6° of rotation occurred in 144 milliseconds between onset and peak, with rotational velocity and acceleration maximum values of 192.9°/s and 4427°/s², respectively. Most student characteristics were similar, but DCs' acceleration means were significantly higher (Kruskal-Wallis P = .019), and experienced students used significantly greater lateral bending at onset (Kruskal-Wallis P = .049) and peak (P = .023). Mean axial rotation for DCs during chiropractic cervical spinal adjustments was less than 34° at peak; most other measures were similar to previously reported findings.

The purpose of this study was to examine sagittal spinal movements during walking with frameless and internal frame backpacks. Twenty adult students from a chiropractic college walked on a treadmill while wearing inertial measurement units mounted on the head, T1 and T12 vertebrae, and sacrum. They walked without a backpack, with a backpack loaded with 6.8 kg, and after 15 minutes walking with the loaded pack. Day 1, they wore a backpack with no structural support; day 2, they wore an internal frame backpack with a hip belt and chest compression straps. Cyclic sagittal flexion and extension endpoints were identified using an application written in the R language. Participants walked with the lumbar spine in slight flexion throughout all trials with both packs; flexion significantly increased with load and with time, more so with the frameless pack. The thoracic region showed progressive extension with load and time, significant only for the frameless pack. The cervical region trended toward progressive extension with load and time, with no significant changes for either pack. In this group of adult students walking on a treadmill, there were trends of increasing lumbar flexion, thoracic extension, and cervical extension, with changes more pronounced with a frameless backpack than one with an internal frame.

The purpose of this study was to analyze hip, shoulder, and elbow movements of a doctor of chiropractic during performance of side-posture chiropractic spinal manipulation. An experienced chiropractor performed lumbar spinal manipulation (ie, chiropractic adjustment) on 10 participants. An inertial measurement unit system was used to record angular motions, and data were analyzed in Excel to identify positional angles at set-up and thrust times, and to generate graphs of time series plots for qualitative assessment of movement patterns. Most motion patterns were qualitatively similar between participants for each joint and plane of motion, though angular magnitudes were often different; but times of thrust were not consistent within the patterns. Positional angles for the left and right shoulders were asymmetrical, as were those for the left and right hips, reflecting their different roles in patient stabilization and thrust. The right elbow displayed only a few degrees of extension during the thrust, reflecting its role in transferring the force from the chiropractor's center of gravity ("body drop"), rather than the upper extremity solely generating the thrust. Most motions had thrust-to-thrust consistency in their patterns, despite trial-to-trial differences in angular magnitudes, suggesting that a DC's performance is repeatable for spinal manipulation. Measurements might be different for other DCs according to differences in professional education, treatment tables of different heights, or patients with different body sizes.

Objective: Force-sensing treatment tables are becoming more commonly used by chiropractic educational institutions. However, when a table-embedded force platform is the sole measurement method, there is little information available about what force-time values instructors and students should expect for side-posture spinal manipulative thrusts. The purpose of this report is to provide force-time values recorded with such a system during side-posture manipulation with human recipients. Methods: Student volunteers were examined by and received lumbar or pelvic side-posture manipulation from experienced chiropractors who were diplomates of the Gonstead Clinical Studies Society. Forces were recorded using proprietary software of a Bertec force platform; force and time data were analyzed with a custom-programmed software tool in Excel. Results: Seven doctors of chiropractic performed 24 thrusts on 23 student recipients. Preload forces, averaging 69.7 N, and thrust loading duration, averaging 167 milliseconds, were similar to previous studies of side-posture manipulation. Peak loads were higher than previous studies, averaging 1010.9 N. Other variables included prethrust liftoff force, times from thrust onset to peak force and peak load to resolution of thrust, and average rates of force loading and unloading. Conclusion: The values we found will be used for reference at our institution and may be useful to instructors at other chiropractic educational institutions, in the teaching of lumbar side-posture manipulation. A caveat is that the values of this study reflect multiple sources of applied force, not solely the force applied directly to the spine.

The primary purposes of this study were to measure axial rotation during supine cervical spinal manipulative therapy (cSMT) and to record recipients' and doctors' perceptions of rotational magnitudes. Experienced doctors of chiropractic (DCs) provided supine cSMT and acted as recipients of cSMT. Participants who received SMT wore inertial measurement units attached to the forehead and sternum for motion capture. Afterward, recipients and DCs completed questionnaires asking about their perceptions of motion. Data were analyzed for magnitudes of axial rotation at peak thrust and correlations with patient and doctor perceptions. Secondary analyses included angular velocity, angular acceleration, and other kinematic variables. We recorded 23 SMT events with 14 DCs. Rotation at thrust peaks averaged 32.4° (17.4°). Doctors' and recipients' perceptions of rotation were higher than measured values 45% and 50% of the time, respectively. Maximum angular velocity and acceleration averaged 221.9°/s (124.9) and 4786.5°/s² (2456.6), respectively. We found no correlation between perceptions and velocity or acceleration; doctors' perceptions had an inverse correlation with measurements. On average, we found rotation during supine cSMT to be 32°. Both DCs and SMT recipients overestimated rotation compared with actual measurements. These factors should be considered in discussions of rotation and SMT.

The purpose of this study was to develop a protocol and a data analysis system for the assessment of postures and movements of doctors of chiropractic during side-posture adjustments (SPAs), otherwise known as side-posture chiropractic spinal manipulation. For this study, an experienced chiropractor performed Gonstead-style lumbar SPAs on 10 participants. We used an inertial measurement unit system to record spinal angular motions and analyzed data with a custom application written in Microsoft Excel. Data collection was successful for all trials. We identified postural angles at the time of set-up and thrust and maximum and minimum angles in a period centered on the thrust. All spinal regions of the chiropractor were flexed during the entire period; otherwise, movement patterns were characterized by biphasic wavelike motions, which begin before the time of the thrust and finish afterward. Within each region and plane of motion, patterns were qualitatively similar between participants, but time of thrust was not consistent within the patterns. There was a wide range of angular velocities, and the fastest was measured in the chiropractor's cervical and thoracic regions. In this study, we developed a protocol and a data analysis system for assessment of chiropractors' postures and movements during SPAs. The protocol may be useful to future investigators who wish to use similar methods for educational purposes or to examine the role of optimal or suboptimal movement patterns in occupational injuries of doctors of chiropractic.

Objective: Faced with COVID-19 safety protocols that severely limited the ability to conduct chiropractic technique instruction in the usual manner, our university invested the resources to develop a new mannequin lab for hands-on training, which would help supplement the loss of person-to-person contact. Methods: Training mannequins could enable student learning of palpation and adjustment skills while avoiding close human–human contact. The university had developed a mannequin over the previous 4 years consisting of a full-sized human torso with individually movable and palpable vertebrae, pelvis, and thighs. In the mannequin, 64 pressure sensors are attached to particular vertebral and skeletal landmarks and provide feedback on palpation location and level of force applied. We assembled 3 teams to produce 20 copies of that mannequin for student use. Results: Mannequins were produced in 7 weeks, and space was built out for a special lab. Faculty members are developing classroom procedures to introduce the mannequin to students, phase in the skills from static and motion palpation, and practice thrust performance. Conclusion: The production run was successful, and the resulting equipment, well-received by students and faculty. In addition to helping teach manual skills, the lab serves as a platform for educational research to test the efficacy of mannequin-based training protocols. With the pressure sensors on known locations along the spine, future research may be able to test the ability of students to identify and contact specific target locations for adjustive thrusts.