ACCRAC AWARD WINNING PAPER
EFFECT OF SAMPLING RATES ON THE QUANTIFICATION OF
FORCES, DURATIONS, AND RATES OF LOADING OF
SIMULATED SIDE POSTURE HIGH-VELOCITY, LOW-
AMPLITUDE LUMBAR SPINE MANIPULATION☆
Maruti Ram Gudavalli, PhD,aJames DeVocht, DC, PhD,aAli Tayh, BS,band Ting Xia, PhDc
Objective: Quantification of chiropractic high-velocity, low-amplitude spinal manipulation (HVLA-SM) may require
biomechanical equipment capable of sampling data at high rates. However, there are few studies reported in the literature
regarding the minimal sampling rate required to record the HVLA-SM force-time profile data accurately and precisely.
The purpose of this study was to investigate the effect of different sampling rates on the quantification of forces,
durations, and rates of loading of simulated side posture lumbar spine HVLA-SM delivered by doctors of chiropractic.
Methods: Five doctors of chiropractic (DCs) and 5 asymptomatic participants were recruited for this study. Force-
time profiles were recorded during (i) 52 simulated HVLA-SM thrusts to a force transducer placed on a force plate by
2 DCs and (ii) 12 lumbar side posture HVLA-SM on 5 participants by 3 DCs. Data sampling rate of the force plate
remained the same at 1000 Hz, whereas the sampling rate of the force transducer varied at 50, 100, 200, and 500 Hz.
The data were reduced using custom-written MATLAB (Mathworks, Inc, Natick, MA) and MathCad (version 15;
Parametric Technologies, Natick, MA) programs and analyzed descriptively.
Results: The average differences in the computed durations and rates of loading are smaller than 5% between 50 and
1000 Hz sampling rates. The differences in the computed preloads and peak loads are smaller than 3%.
Conclusions: The small differences observed in the characteristics of force-time profiles of simulated manual HVLA-
SM thrusts measured using various sampling rates suggest that a sampling rate as low as 50 to 100 Hz may be
sufficient. The results are applicable to the manipulation performed in this study: manual side posture lumbar spine
HVLA-SM. (J Manipulative Physiol Ther 2013;36:261-266)
Key Indexing Terms: Biomechanics; Manipulation, Spinal; Chiropractic; Manual Therapy
diversified or Gonstead style lumbar, lumbosacral, or
sacroiliac joint chiropractic manipulation/adjustment). Par-
ticipants are placed in a lateral recumbent or side-lying
position, with the superior or free hip and knee flexed and
adducted across the midline. The lumbar spine and pelvis
remained in a neutral position, approximately perpendicular
to the adjusting table surface. A quick, short controlled
movement of the clinician's shoulder, arm, and hand
combined with a slight body drop provide the single impulse
load or thrust to the contact point. Because spinal
of the associated force-time characteristics is important.1-3
Forces applied by doctors to patients can be measured
directly using a force transducer at the doctor/patient
interface (eg, hand to spine).4-12The forces measured are
referred to as applied or contact forces. Van Zoest et al13,14
igh-velocity, low-amplitude spinal manipulation
(HVLA-SM) is a commonly used procedure in
chiropractic practice (eg, also known as side-lying
aAssociate Professor, Palmer Center for Chiropractic Research,
bDesign Engineer, Vizient LLC, Bettendorf, Iowa.
cAssistant Professor, Palmer Center for Chiropractic Research,
☆This is an open-access article distributed under the terms of
the Creative Commons Attribution-NonCommercial-ShareAlike
License, which permits non-commercial use, distribution, and
reproduction in any medium, provided the original author and
source are credited.
Submit requests for reprint to Maruti Ram Gudavalli, PhD,
Associate Professor, Palmer Center for Chiropractic Research, 741
Brady St, Davenport, IA 52803
Paper submitted April 26, 2012; in revised form December 21,
2012; accepted January 18, 2013.
Copyright © 2013 The Authors. Published by Elsevier Inc. All
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Manipulation Force Time CharacteristicsJune 2013