Characteristics of Forces at the Clinician-Patient and Patient-Table Interfaces During Thoracic Spinal Manipulation in Asymptomatic Adults are Consistent with Deformable Body Models

Thomas J1 , Murphy T1 , Tran S1 , Howarth SJ1 , Starmer D1 , Funabashi M1,2 1CanadianMemorialChiropracticCollege, 2Université du Québec à Trois-Rivières

Abstract

Investigating all forces exerted on the patient's body during high-velocity, low-amplitude spinal manipulative therapy (SMT) remains fundamental to elucidate how these may contribute to SMT's effects. Previous conflicting findings preclude our understanding of the relationship between SMT forces acting at the clinician-patient and patient-table interfaces. This study aimed to quantify forces at the clinician-participant and participanttable interfaces during thoracic SMT in asymptomatic adults. An experienced clinician provided a posterior to anterior SMT centered to T7 transverse processes using predetermined force-time characteristics to 40 asymptomatic volunteers (20 females; average age = 27.2 [4.9] y). Forces at the clinician-participant interface were recorded by triaxial load cells; whereas, forces at the participant-table interface were recorded by the force-sensing table technology. Preload force, total peak force, time to peak, and loading rate at each interface were analyzed descriptively. Total peak vertical forces at the clinician-participant interface averaged 532 (71) N while total peak forces at the participant-table interface averaged 658 (33) N. Forces at the participant-table interface were, on average, 1.27 (0.25) times larger than the ones at the clinician-participant interface. Larger forces at the participant-table interface compared with the ones at the clinician-participant interface during thoracic SMT are consistent with mathematical models developed to investigate thoracic impact simulating a dynamic forcedeflection response.

OriginallypublishedinJournalofAppliedBiomechanics, 2022Feb1;38(1):39-46

ReproducedwithpermissionfromHumanKinetics Publishers

Access online:doi:10.1123/jab.2021-0255