FORCE-TIME PROFILE CHARACTERIZATION OF THE MCTIMONEY TOGGLE-TORQUE-RECOIL TECHNIQUE Christopher J. Colloca, DC, a Christina Cunliffe, DC, PhD, b Marisa H. Pinnock, DC, MSc(Chiro), c Young-Kwan Kim, PhD, d and Richard N. Hinrichs, PhD e ABSTRACT Objectives: The purpose of this study was to characterize the force-time profile of the McTimoney toggle-torque-recoil (MTTR) technique. Methods: Two licensed chiropractors trained in the McTimoney Method applied MTTR thrusts to a tabletop where a dynamic load cell had been mounted. Each clinician applied 10 thrusts (5 with each hand) to the load cell in a repeated measures design. Peak forces, time durations, and time to peak force were computed from each of the force-time histories. Descriptive statistics were performed to compare the forces, durations, and times to peak force of the MTTR thrusts. A Mann-Whitney U test compared variables between the 2 clinicians, whereas a Wilcoxon signed-rank test compared right- and left-handed thrusts within clinicians. Results: Considering all MTTR thrusts, the average peak force was 87.22 N (SD = 24.18 N), the average overall thrust duration was 36.38 milliseconds (SD = 9.58 milliseconds), and the average time to peak force was 12.31 milliseconds (S.D. = 4.39 milliseconds). No significant differences in mean peak force, duration, or time to peak force were observed between clinicians. When comparing intraclinician right and left hand thrusts, differences in peak force and duration were observed individually (P b .05). Conclusion: For the 2 chiropractors tested, MTTR thrusts were relatively lower in peak force and appreciably faster than other commonly used chiropractic techniques. Future work aims to investigate the relationships between the force- time profiles of MTTR thrusts and resultant physiologic and clinical responses. (J Manipulative Physiol Ther 2009;32:372-378) Key Indexing Terms: Biomechanics; Chiropractic; Manipulation, Spinal A variety of chiropractic techniques have been devel- oped to provide doctors of chiropractic with choices of technique application for a particular patient or condition in the application of chiropractic adjustments. Specifically, manual articular manipulative and adjusting procedures have been classified into four categories to better describe the technique and mechanism of force production: Specific contact thrust procedures (ie, high-velocity, low- amplitude thrusts), nonspecific contact thrust procedures (ie, mobilization), manual-force, mechanically-assisted proce- dures (ie, drop tables or flexion-distraction tables), and mechanical-force, manually-assisted (MFMA) procedures (ie, stationary or handheld instruments). 1 Biomechanical investigations of individual differences in performance have begun to be studied for the purposes of education and assessing proficiency of particular technique strategies. 2-4 Common among all technique categories are the inherent goals of optimizing the potential for therapeutic benefits, while maximizing the comfort and safety of the patient and maximizing the efficiency of the thrust application. 5 Developed by the late John McTimoney in the 1950s in the United Kingdom, 6 the McTimoney method is a light, whole-body approach to chiropractic care which is now estimated to be used by over a quarter of the chiropractors in the United Kingdom. 7 Based on the toggle-recoil technique developed by Palmer, 8 McTimoney adapted the classic hand position to better isolate the pisiform bone to ensure a more a Graduate student, Biomechanics Laboratory, Exercise and Sport Research Institute, Department of Kinesiology, Arizona State University, Tempe, Ariz. b President, McTimoney College of Chiropractic, Abingdon, Oxfordshire, United Kingdom. c Private Practice, Chevington Chiropractic Clinic, Surrey, United Kingdom. d Post doctoral assistant, Biomechanics Laboratory, Exercise and Sport Research Institute, Department of Kinesiology, Arizona State University, Tempe, Ariz. e Director, Biomechanics Laboratory, Exercise and Sport Research Institute, Department of Kinesiology, Arizona State University, Tempe, Ariz. Submit requests for reprints to: Christopher J. Colloca, DC, 101 South Roosevelt Avenue, Chandler, AZ 84226 (e-mail: drc100@aol.com). Paper submitted May 27, 2008; in revised form March 8, 2009; accepted April 6, 2009. 0161-4754/$36.00 Copyright © 2009 by National University of Health Sciences. doi:10.1016/j.jmpt.2009.04.005 372