Carla R Lima1, Randall S Sozio2, AaMarryah C Law3, Alicia J Nelson3, Harshvardhan Singh4, Christopher P Hurt4, Peng Li5, William R Reed6. 1. Rehabilitation Science Program, University of Alabama at Birmingham, Birmingham, Alabama. 2. Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa. 3. CORD Program, University of Alabama at Birmingham, Birmingham, Alabama. 4. Physical Therapy Department, University of Alabama at Birmingham, Birmingham, Alabama. 5. School of Nursing, University of Alabama at Birmingham, Birmingham, Alabama. 6. Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa; Physical Therapy Department, University of Alabama at Birmingham, Birmingham, Alabama. Electronic address: wreed@uab.edu.
Abstract
OBJECTIVE: The purpose of this study was to characterize trunk muscle spindle responses immediately after high-velocity, low-amplitude spinal manipulation (HVLA-SM) delivered at various thrust magnitudes and thrust durations. METHODS: Secondary analysis from multiple studies involving anesthetized adult cats (N = 70; 2.3-6.0 kg) receiving L6 HVLA-SM. Muscle spindle afferent recordings were obtained from L6 dorsal rootlets before, during, and immediately after HVLA-SM. L6 HVLA-SM was delivered posteriorly-to-anteriorly using a feedback motor with peak thrust magnitudes of 25%, 55%, and 85% of cat body weight (BW) and thrust durations of 25, 50, 75, 100, 150, 200, and 250 ms. Time to the first action potential and muscle spindle discharge frequency at 1 and 2 seconds post-HVLA-SM were determined. RESULTS: A significant association between HVLA-SM thrust magnitude and immediate (≤2 s) muscle spindle response was found (P < .001). For non-control thrust magnitude, pairwise comparisons (25%, 55%, 85% BW), 55% BW thrust magnitude had the most consistent effect on immediate post-HVLA-SM discharge outcomes (false discovery rate < 0.05). No significant association was found between thrust duration and immediate post-HVLA-SM muscle spindle response (P > .05). CONCLUSION: The present study found that HVLA-SM thrust magnitudes delivered at 55% BW were more likely to affect immediate (≤2 s) post-HVLA-SM muscle spindle response.
OBJECTIVE: The purpose of this study was to characterize trunk muscle spindle responses immediately after high-velocity, low-amplitude spinal manipulation (HVLA-SM) delivered at various thrust magnitudes and thrust durations. METHODS: Secondary analysis from multiple studies involving anesthetized adult cats (N = 70; 2.3-6.0 kg) receiving L6 HVLA-SM. Muscle spindle afferent recordings were obtained from L6 dorsal rootlets before, during, and immediately after HVLA-SM. L6 HVLA-SM was delivered posteriorly-to-anteriorly using a feedback motor with peak thrust magnitudes of 25%, 55%, and 85% of cat body weight (BW) and thrust durations of 25, 50, 75, 100, 150, 200, and 250 ms. Time to the first action potential and muscle spindle discharge frequency at 1 and 2 seconds post-HVLA-SM were determined. RESULTS: A significant association between HVLA-SM thrust magnitude and immediate (≤2 s) muscle spindle response was found (P < .001). For non-control thrust magnitude, pairwise comparisons (25%, 55%, 85% BW), 55% BW thrust magnitude had the most consistent effect on immediate post-HVLA-SM discharge outcomes (false discovery rate < 0.05). No significant association was found between thrust duration and immediate post-HVLA-SM muscle spindle response (P > .05). CONCLUSION: The present study found that HVLA-SM thrust magnitudes delivered at 55% BW were more likely to affect immediate (≤2 s) post-HVLA-SM muscle spindle response.
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: William R Reed; Dong-Yuan Cao; Cynthia R Long; Gregory N Kawchuk; Joel G Pickar Journal: Evid Based Complement Alternat Med Date: 2013-01-20 Impact factor: 2.629