Thrust Magnitudes, Rates, and 3-Dimensional Directions Delivered in Simulated Lumbar Spine High-Velocity, Low-Amplitude Manipulation

Assessment of forces during side-posture adjustment with the use of a table-embedded force plate: Reference values for education

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.

Development of a mannequin lab for clinical training in a chiropractic program

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.

A reliability study of a novel visual ischemic palpation scale in an experimental setting

BACKGROUND

Manual palpation is an important part of the clinical examination and generally it has low reliability. The aim of this study was to assess the reliability of a novel method for discriminating 3 different levels of palpation force.

METHODS

This reliability study included 96 healthy physiotherapists and physiotherapy students, who have been taught a new palpation graduated procedure called Visual Ischemic Palpatory Scale (VIPS), aimed to classify the applied pressure based on the finger's ischemia. Force was recorded by a force measurement system putting sensor over a rigid surface. To study the characteristic of VIPS the analysis of variance (ANOVA), Spearman rank correlation coefficient, Intraclass Correlation Coefficient (ICC), Standard Error of Measurements (SEM), and Minimal Detectable Change (MDC) were calculated.

RESULTS

Three distinct degrees were found with distinct forces expression: 1st degree 76.04 g (95% CI 65.86-86.22), 2nd degree 307.87 g (95% CI 263.29-352.44) and 3rd degree 1319.48 g (CI 1204.73-1434.23). Male participants significantly recorded a greater force than females. Good to excellent reliability across degrees were found (0.89 [95% CI: 0.82-0.97]), and final agreement found that more than 65.6% of sample recorded a force in the cut-offs identified. SEM values became bigger as the recorded force increased and MDC were equal to 48.94 g, 188.73 g, and 379.24 g for 1st, 2nd, and 3rd degree, respectively.

CONCLUSIONS

VIPS would appear to have three distinct degrees, sex dependent, with specific force expression for each degree and a good to excellent intra-rater reliability, but a poor agreement between raters.

The degenerative lumbar disc: not a disease, but still an important consideration for OMPT practice: a review of the history and science of discogenic instability

BACKGROUND

A recent AAOMPT position paper was published that opposed the use of the term 'degenerative disc disease' (DDD), in large part because it appears to be a common age-related finding. While common, there are significant physiologic and biomechanical changes that occur as a result of discogenic degeneration, which are relevant to consider during the practice of manual therapy.

METHODS

A narrative review provides an overview of these considerations, including a historical perspective of discogenic instability, the role of the disc as a pain generator, the basic science of a combined biomechanical and physiologic cycle of degeneration and subsequent discogenic instability, the influence of rotation on the degenerative segment, the implications of these factors for manual therapy practice, and a perspective on an evidence-based treatment approach to patients with concurrent low back pain and discogenic degeneration.

CONCLUSIONS

As we consider the role of imaging findings such as DDD, we pose the following question: Do our manual interventions reflect the scientifically proven biomechanical aspects of DDD, or have we chosen to ignore the helpful science as we discard the harmful diagnostic label?

Changes in adjustment force, speed, and direction factors in chiropractic students after 10 weeks undergoing standard technique training

OBJECTIVE

To assess the force profiles of high-velocity low-amplitude thrusts delivered to a mannequin on a force platform by novice students given only verbal instructions.

METHODS

Student volunteers untrained in adjusting delivered a series of adjustments to a mannequin on a force platform. Participants performed 3 light, 3 normal, and 3 heavy thrusts on 5 listings specifying contact point, hand, and direction. Force profiles were analyzed for speed and amplitude, consistency, and force discrimination. Two recording sessions occurred 10 weeks apart.

RESULTS

Sixteen participants (11 females, 5 male) completed the study. Peak forces ranged from 880 to 202 N for heavy thrusts and 322- to 66 N for light thrusts. Thrust rate was from 8.1 to 1.8 Newtons per millisecond. Average coefficients of variability (CV = STD/mean) at each load level (initial/final) were heavy: 17%/15%; normal: 16%/15%; and light: 20%/20%, with 0 as ideal. A force ratio measured students' abilities to distinguish thrust magnitude. The heavy/normal ratio (initial/final) was 1.35/1.39, and the light/normal ratio was 0.70/0.67.

CONCLUSIONS

At this point, without force feedback being used in the classroom, novice students can produce thrusts that look like those of their teachers and of experienced practitioners, but they may not produce similar speed and force values. They are consistent within and between sessions and can discriminate between light and heavy loads. A natural next step in our educational research will be to measure adjustment factors on more experienced cohorts of students with and without the presence of force-feedback training apparatus.