title: A standardized representation of spinal quality of motion.
abstract: The experimentally determined torque-rotation curve of the lumbar spine is mathematically described with a proposed dual-inflection point Boltzmann equation. The result is a method for describing functional spinal unit motion data. The benefit of the model is that each of the coefficients has a specific meaning in relation to the torque-rotation curve: the points A and B identify the respective minimum and maximum rotations of the functional spinal unit, m1 and m2 indicate the inflection points of the curve where the stiffness changes markedly, and α1 and α2 are associated with the rates of change of the curve at m1 and m2, respectively. The dual-inflection point Boltzmann captures the full quality of motion of the spinal segment and can also be used to derive relevant parameters such as range of motion, midrange stiffness, and hysteresis.
authors.affiliation: Mechanical Engineering Department, Brigham Young University, Provo, UT, USA.
authors.forename: Shannon A
authors.initials: SA
authors.lastname: Zirbel
authors.affiliation: Mechanical Engineering Department, Brigham Young University, Provo, UT, USA.
authors.forename: Dean K
authors.initials: DK
authors.lastname: Stolworthy
authors.affiliation: Mechanical Engineering Department, Brigham Young University, Provo, UT, USA.
authors.forename: Larry L
authors.initials: LL
authors.lastname: Howell
authors.affiliation: Mechanical Engineering Department, Brigham Young University, Provo, UT, USA abowden@byu.edu.
authors.forename: Anton E
authors.initials: AE
authors.lastname: Bowden
mesh_terms: D003198:Computer Simulation; D004548:Elasticity / Q000502:physiology; D008159:Lumbar Vertebrae / Q000033:anatomy & histology* / Q000502:physiology*; D008954:Models, Biological; D010808:Physical Examination / Q000592:standards*; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D013718:Tensile Strength / Q000502:physiology; D019415:Torque; D014481:United States; D021801:Zygapophyseal Joint / Q000033:anatomy & histology / Q000502:physiology
keywords: Boltzmann sigmoid; Lumbar spine; quality of motion; spine modeling; torque–rotation