William R Reed1, Cynthia R Long2, Gregory N Kawchuk3, Joel G Pickar4. 1. Associate Professor, Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa. 2. Professor, Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa. 3. Associate Professor, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada. 4. Professor Emeritus, Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa. Electronic address: jgpickar@live.com.
Abstract
OBJECTIVE: The purpose of this study was to determine how the preload that precedes a high-velocity, low-amplitude spinal manipulation (HVLA-SM) affects muscle spindle input from lumbar paraspinal muscles both during and after the HVLA-SM. METHODS: Primary afferent activity from muscle spindles in lumbar paraspinal muscles were recorded from the L6 dorsal root in anesthetized cats. High-velocity, low-amplitude spinal manipulation of the L6 vertebra was preceded either by no preload or systematic changes in the preload magnitude, duration, and the presence or absence of a downward incisural point. Immediate effects of preload on muscle spindle responses to the HVLA-SM were determined by comparing mean instantaneous discharge frequencies (MIF) during the HVLA-SM's thrust phase with baseline. Longer lasting effects of preload on spindle responses to the HVLA-SM were determined by comparing MIF during slow ramp and hold movement of the L6 vertebra before and after the HVLA-SM. RESULTS: The smaller compared with the larger preload magnitude and the longer compared with the shorter preload duration significantly increased (P = .02 and P = .04, respectively) muscle spindle responses during the HVLA-SM thrust. The absence of preload had the greatest effect on the change in MIF. Interactions between preload magnitude, duration, and downward incisural point often produced statistically significant but arguably physiologically modest changes in the passive signaling properties of the muscle spindle after the manipulation. CONCLUSION: Because preload parameters in this animal model were shown to affect neural responses to an HVLA-SM, preload characteristics should be taken into consideration when judging this intervention's therapeutic benefit in both clinical efficacy studies and in clinical practice.
OBJECTIVE: The purpose of this study was to determine how the preload that precedes a high-velocity, low-amplitude spinal manipulation (HVLA-SM) affects muscle spindle input from lumbar paraspinal muscles both during and after the HVLA-SM. METHODS: Primary afferent activity from muscle spindles in lumbar paraspinal muscles were recorded from the L6 dorsal root in anesthetized cats. High-velocity, low-amplitude spinal manipulation of the L6 vertebra was preceded either by no preload or systematic changes in the preload magnitude, duration, and the presence or absence of a downward incisural point. Immediate effects of preload on muscle spindle responses to the HVLA-SM were determined by comparing mean instantaneous discharge frequencies (MIF) during the HVLA-SM's thrust phase with baseline. Longer lasting effects of preload on spindle responses to the HVLA-SM were determined by comparing MIF during slow ramp and hold movement of the L6 vertebra before and after the HVLA-SM. RESULTS: The smaller compared with the larger preload magnitude and the longer compared with the shorter preload duration significantly increased (P = .02 and P = .04, respectively) muscle spindle responses during the HVLA-SM thrust. The absence of preload had the greatest effect on the change in MIF. Interactions between preload magnitude, duration, and downward incisural point often produced statistically significant but arguably physiologically modest changes in the passive signaling properties of the muscle spindle after the manipulation. CONCLUSION: Because preload parameters in this animal model were shown to affect neural responses to an HVLA-SM, preload characteristics should be taken into consideration when judging this intervention's therapeutic benefit in both clinical efficacy studies and in clinical practice.
Authors: Dong-Yuan Cao; William R Reed; Cynthia R Long; Gregory N Kawchuk; Joel G Pickar Journal: J Manipulative Physiol Ther Date: 2013-02 Impact factor: 1.437
Authors: William R Reed; Joel G Pickar; Randall S Sozio; Michael A K Liebschner; Joshua W Little; Maruti R Gudavalli Journal: J Manipulative Physiol Ther Date: 2017-06-17 Impact factor: 1.437
Authors: Charles W Gay; Michael E Robinson; Steven Z George; William M Perlstein; Mark D Bishop Journal: J Manipulative Physiol Ther Date: 2014-10-03 Impact factor: 1.437
Authors: William R Reed; Cynthia R Long; Gregory N Kawchuk; Randall S Sozio; Joel G Pickar Journal: Spine (Phila Pa 1976) Date: 2018-01-01 Impact factor: 3.241
Authors: Carla R Lima; Randall S Sozio; AaMarryah C Law; Alicia J Nelson; Harshvardhan Singh; Christopher P Hurt; Peng Li; William R Reed Journal: J Manipulative Physiol Ther Date: 2021-06-05 Impact factor: 1.300
Authors: François Nougarou; Isabelle Pagé; Michel Loranger; Claude Dugas; Martin Descarreaux Journal: BMC Complement Altern Med Date: 2016-06-02 Impact factor: 3.659
Authors: William R Reed; Michael A K Liebschner; Randall S Sozio; Joel G Pickar; Maruti R Gudavalli Journal: J Nov Physiother Phys Rehabil Date: 2015-04-06