Differing Characteristics of Human-Shaped Visual Stimuli Affect Clinicians' Dosage of a Spinal Manipulative Thrust on a Low-Fidelity Model: A Cross-Sectional Study

Steven R Passmore; Quinn Malone; Brian MacNeil; Elizabeth Sanli; David Gonzalez

doi:10.1016/j.jmpt.2022.06.005

Differing Characteristics of Human-Shaped Visual Stimuli Affect Clinicians' Dosage of a Spinal Manipulative Thrust on a Low-Fidelity Model: A Cross-Sectional Study

J Manipulative Physiol Ther. 2022 Mar-Apr;45(3):171-178. doi: 10.1016/j.jmpt.2022.06.005. Epub 2022 Jul 28.

Authors

Steven R Passmore¹, Quinn Malone², Brian MacNeil³, Elizabeth Sanli⁴, David Gonzalez⁵

Affiliations

¹ Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada. Electronic address: steven.passmore@umanitoba.ca.
² Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada.
³ College of Rehabilitation Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
⁴ School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
⁵ Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.

PMID: 35907658
DOI: 10.1016/j.jmpt.2022.06.005

Abstract

Objective: The purpose of this study was to determine whether chiropractic clinicians modulate spinal manipulation (SM) thrust characteristics based on visual perception of simulated human silhouette attributes.

Methods: We performed a cross-sectional within-participant design with 8 experienced chiropractors. During each trial, participants observed a human-shaped life-sized silhouette of a mock patient and delivered an SM thrust on a low-fidelity thoracic spine model based on their visual perception. Silhouettes varied on the following 3 factors: apparent sex (male or female silhouette), height (short, average, tall), and body mass index (BMI) (underweight, healthy, obese). Each combination was presented 6 times for a total of 108 trials in random order. Outcome measures included peak thrust force, thrust duration, peak preload force, peak acceleration, time to peak acceleration, and rate of force application. A 3-way repeated measures analysis of variance model was used to for each variable, followed by Tukey's honestly significant difference on significant interactions.

Results: Peak thrust force was reduced when apparent sex of the presented silhouette was female (F_1,7 = 5.70, P = .048). Thrust duration was largely invariant, except that a BMI by height interaction revealed a longer duration occurred for healthy tall participants than healthy short participants (F_4,28 = 4.34, P = .007). Compared to an image depicting obese BMI, an image appearing underweight lead to reduced peak acceleration (F_2,5 = 6.756, P = .009). Clinician time to peak acceleration was reduced in short compared to tall silhouettes (t₇ = 2.20, P = .032).

Conclusion: Visual perception of simulated human silhouette attributes, including apparent sex, height, and BMI, influenced SM dose characteristics through both kinetic and kinematic measures. The results suggest that visual information from mock patients affects the decision-making of chiropractic clinicians delivering SM thrusts.

Keywords: Chiropractic; Dose, Maximal Tolerated; Manipulation, Spinal; Palpation; Spine; Visual Perception.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Chiropractic* / methods
Cross-Sectional Studies
Female
Humans
Male
Manipulation, Spinal* / methods
Obesity / therapy
Thinness