title: Development of a Linked Segment Model to Derive Patient Low Back Reaction Forces and Moments During High-Velocity Low-Amplitude Spinal Manipulation.
abstract: 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).
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Associate Professor, McMorland Family Research Chair in Mechanobiology, Graduate Education and Research Programs, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada. Electronic address: showarth@cmcc.ca.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Howarth
authors.affiliation: Graduate Resident, Department of Graduate Education and Research Programs, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: D'Angelo
authors.affiliation: Professor, Department of Graduate Education and Research Programs, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada.
authors.forename: John J
authors.initials: JJ
authors.lastname: Triano
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D020393:Manipulation, Spinal; D008954:Models, Biological; D018482:Muscle, Skeletal; D011187:Posture; D015203:Reproducibility of Results; D016474:Weight-Bearing
keywords: Biomechanics; Chiropractic; Key Indexing Terms; Low Back Pain; Lumbar Region