ARTICLE IN PRESS
Manual Therapy 9 (2004) 164–172
www.elsevier.com/locate/math
Original article
A survey on the importance of lumbar coupling biomechanics in
physiotherapy practice
Chad Cooka,*, Christopher Showalterb
a
Department of Rehabilitation Sciences, Texas Tech University Health Sciences Centre, Odessa, 800 West Fourth Street, Odessa, TX 79763, USA
b
Maitland Australian Physiotherapy Seminars, P.O. Box 1244, Cutchogue, NY 11935, USA
Received 30 June 2003; received in revised form 29 January 2004; accepted 4 March 2004
Abstract
Knowledge of lumbar coupling biomechanics is foundational in many manual therapy disciplines. 3-D studies of lumbar coupling
indicate that coupling direction may not be predictable. The purpose of this study was to investigate physiotherapists’ perception of
importance of lumbar coupling for validation of manual therapy, necessity in treatment, and perceived direction of lumbar coupling
biomechanics. A sample of 369 physiotherapists within the United States volunteered to participate in this study. An ologit
regression analysis investigated factors associated with perception of lumbar coupling. A Fleiss Kappa determined the agreement of
coupling direction among physiotherapists. The majority of physiotherapists indicated that lumbar coupling biomechanics were
important or very important, frequently used during treatment, and necessary for validation of manual therapy. The ologit
regressions identified that the importance placed upon lumbar coupling biomechanics is highly related toward therapists’ preconcept of coupling. Kappa values for the five spinal segments were negative indicating worse than chance agreement: L122 ¼
0:10; L223 ¼ 0:11; L324 ¼ 0:09; L425 ¼ 0:10; and L52S1 ¼ 0:09: The poor Kappa values, strong pre-conceptual
perceptions of coupling necessity, and the importance placed upon lumbar coupling for treatment could lead to disparities among
physiotherapists in lumbar manual therapy assessment and treatment.
r 2004 Elsevier Ltd. All rights reserved.
1. Introduction
Biomechanical analysis, including investigation of
coupled motion is often identified as essential in the
assessment and treatment of low back pain (Cassidy,
1976; Grice, 1979; Pearcy et al., 1985; Gomez, 1994;
Panjabi et al., 1994; Mellin et al., 1995; Winkel et al.,
1996). There are two principle components of lumbar
coupling; quantity of motion, used in detection of hypo
and hypermobility and direction of coupling behaviour.
It has been suggested that the link between pathology of
the lumbar spine may be best represented by addressing
the pattern or direction of coupling behaviour (Fryette,
1954; Faye, 1984; Gertzbein et al., 1986; Plaugher, 1993;
Gracovetsky et al., 1995; Winkel et al., 1996; Lund et al.,
2002). Others have suggested that the quantity of
lumbar coupling behaviour is beneficial in assessment
and treatment (Pearcy et al., 1985; Panjabi et al., 1994;
*Corresponding author. Tel.: +1-915-335-5370; fax: +1-915-3355365.
E-mail address: [email protected] (C. Cook).
1356-689X/$ - see front matter r 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.math.2004.03.003
Harrison et al., 1998). The most controversial of the two
assessment methods is the theory of directional lumbar
coupling, a theory based on the invalidated premise that
a ‘‘normal’’ lumbar coupling pattern exists in nonpathological individuals (Panjabi et al., 1994; Harrison
et al., 1998; Gibbons and Tehan, 2001).
Many manual therapy disciplines base specific mobilization, manipulation, and muscle energy techniques
on selected theories of lumbar coupling direction
(Stoddard, 1972; Beal, 1989; Hartman, 1997). Often, a
specific technique requires pre-positioning of for spinal
segment apposition or movement into a desired coupling
direction. During apposition, the clinician will generally
side-bend, adjust the sagittal plane position of the spine,
and then rotate to lock the level above or below the
targeted segment. These theories are inconsistently
reported, lack empirical validation, and are generally
defined through ‘‘expert-based’’ learning models
(Harrison et al., 1998; Cook, 2003). The feasibility exists,
that if practicing therapists do not share consistent
directional coupling pattern expectations, the results of
their assessment and treatment may be dissimilar.
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C. Cook, C. Showalter / Manual Therapy 9 (2004) 164–172
1.1. Coupling definition
Coupled motion is the rotation or translation of a
vertebral body about or along one axis that is consistently
associated with the main rotation or translation about
another axis (Panjabi et al., 1992). During movement,
translation occurs when movement is such that all
particles within that segment move in the same direction
with the same velocity (Panjabi et al., 1992). With
movement, rotation occurs as a spinning or angular
displacement of the vertebral body around some axis.
Biomechanical coupling is three-dimensional (3-D)
and takes place within six degrees of freedom. The six
degrees of freedom can translate along and rotate about
each orthogonal axis (Panjabi et al., 1992). The 3-D
motions in humans correspond to flexion/extension,
rotation, and side bending forces; one specific movement
initiation (such as side bending) theoretically activates
movement in the other five component motions. The
behaviour of the coupled pattern is dependent on the
first motion of initiation (e.g., side bending), the posture
of the spine, and the pathology of the segment (Panjabi
et al., 1989).
1.2. Coupling measurement and findings
The foundational works on coupling mechanics used
observation or controversial two-dimensional (2-D)
radiographic imagery (Harrison et al., 1998). Past 2-D
studies involved cadaveric tissue, X-rays of live subjects,
or single X-rays of segments, and used a small sample of
subjects (Evans and Lissner, 1959; Harrison et al., 1998).
Prior to 1969, only 2-D studies were executed for spinal
coupling, signifying that any study performed prior to
1969 encompassed these errant methods (Harrison et al.,
1998).
2-D imagery leads to magnification errors, projection
of translations as rotations, rotations as translations,
and misleading results (Panjabi et al., 1994; Harrison
et al., 1996, 1998). The most frequently used method of
2-D imagery involves lateral stress radiograms, a
notoriously unreliable method of analysis that is still
commonly used today (Nelson, 1993; Harrison et al.,
1999). Basing the coupling pattern on observation and
potentially flawed 2-D radiographic methods, may be
one of the reasons such poor continuity existed among
165
past researchers. Table 1 outlines early 2-D lumbar
coupling theories.
Contemporary studies have used three-dimensional
(3-D) assessment, which more accurately measures the
six degrees of freedom associated with coupling motion
(Olin et al., 1976; Rab and Chao, 1977; Stokes et al.,
1980). The majority of 3-D coupling studies have
investigated coupled lumbar behaviour with side bending initiation while in a neutral postural position
(Schultz et al., 1979; Pearcy and Tibrewal, 1984;
McGlashen et al., 1987; Panjabi et al., 1989; Vincenzino
and Twomey, 1993; Panjabi et al., 1994; Cholewicki
et al., 1996). Most studies found that coupling direction
was dependent upon the level of the spine more so than
whether the segment was from a live or cadaveric
specimen (Panjabi et al., 1994). Findings of studies
investigating side bending initiated coupled motion in
neutral, extension, and flexion also display variability
and are presented in Table 2.
1.3. Purpose of the study
There were two purposes to this study. Firstly, we
planned to investigate which variables are associated
with the coupling importance in determination of use,
validation, and frequency of use during practice.
Secondly, to investigate therapists’ perception of directional coupling biomechanics of the lumbar spine in a
non-pathological individual which would identify if
clinicians agree on a predetermined coupling direction.
The literature is inconsistent in identifying a common
lumbar coupling pattern, therefore it was feasible that
disparity existed among practicing clinicians. If disparity
was found to exist in directional coupling knowledge,
and if there was a suggested necessity of lumbar
coupling knowledge by many manual therapists, the
occurrence of variable assessment and treatment continuity among clinicians was thought to be likely.
2. Materials and methods
2.1. Sample
Three hundred and sixty-nine physiotherapists participated in this study. The demographic information
Table 1
Coupled lumbar motion with side bending initiation (neutral spine). Classic observation or 2-D studies
Author
L1–2
L2–3
L3–4
L4–5
L5–S1
Lovett (1905)
Fryette (1954)
Stoddard (1959)
Kapandji (1974)
Rolander (1966)
Same
Opposite
Opposite
Opposite
None
Same
Opposite
Opposite
Opposite
None
Same
Opposite
Opposite
Opposite
None
Same
Opposite
Opposite
Opposite
None
Same
Opposite
Opposite
Opposite
None
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C. Cook, C. Showalter / Manual Therapy 9 (2004) 164–172
Table 2
Coupled lumbar motion with side bending initiation (neutral, extension, and flexed spine) 3-D studies on asymptomatic subjects
Author
L1–2
L2–3
L3–4
L4–5
L5–S1
Neutral spine
Schultz et al. (1979)
Pearcy and Tibrewal (1984)
McGlashen et al. (1987)
Panjabi et al. (1989)
Panjabi et al. (1994)
Cholewicki et al. (1996)
None
None
None
None or same
None
Opposite or none
None
Opposite
None
Opposite
Opposite
Opposite or none
None
Opposite
None
Opposite
Opposite
Opposite or none
None
Opposite
None
Opposite
Opposite
Same
None
Opposite or none
None
Opposite
Opposite
Opposite
Extended spine
Schultz et al. (1979)
Vincenzino and Twomey (1993)
Panjabi et al. (1989)
None
Opposite
Same or none
None
Same
Opposite
None
Opposite
Opposite
None
Same
Opposite
None
Opposite
Opposite
Flexed spine
Vincenzino and Twomey (1993)
Panjabi et al. (1989)
Same or none
Same or opposite
Opposite
Opposite
Same
Opposite
Opposite
Opposite
Same or none
Opposite
including background of this sample is presented in
Table 3. The physiotherapists were voluntary members
of a continuing education course entitled ‘‘Intermediate
Spinal Mobilization,’’ administered at different locations in the contiguous United States. This course was
selected because it was the first course in a manual
therapy series and the course participants represented
diverse backgrounds. The survey was voluntary and
approved by the local University Institutional and
Ethics Review Board.
2.2. Procedure
The survey was administered during the pre-registration period, prior to the initiation of the coursework.
This prevented a pre-biasing regarding lumbar coupling
biomechanics and allowed the subject to record their
response based on their present knowledge of spinal
coupling. The physiotherapists were provided written
instructions requesting that they answer the questions to
the best of their ability. The survey consisted of 11
questions; the first four consisting of Likert-type
questionnaires associated with (1) How important do
you feel the theory of lumbar coupling biomechanics is
in your application of manual therapy? (2) How
important do you feel lumbar coupling biomechanics
is in validating manual therapy? (3) How often do you
consider or use lumbar coupling biomechanics during
your manual therapy treatment? and (4) How often do
you use manual therapy in your treatment of the lumbar
spine? Further questions were associated with frequency
of manual therapy course attendance, manual therapy
background or discipline, educational degree, years of
practice experience, age, and gender.
Since most manual therapy techniques include side
bending initiation methods (Stoddard, 1972; Beal, 1989;
Kappler, 1989; Nyberg, 1993; Hartman, 1997), a
Table 3
Demographics of survey participants
Age
20–29
30–39
40–49
50–59
144
171
50
4
Gender
Male
Female
155
214
Years of experience
0–5 years
6–10 years
11–20 years
Greater than 20
218
98
46
7
Physical therapy education
Bachelors
Masters
Doctoral
168
191
10
Background
Cyriax
Maitland
McKenzie
Paris
Other—not designated
None
Osteopathic
Kaltenbourne
IAOMa
Mulligan
Grimsby
NAIOMTb
28
76
126
29
47
33
2
12
3
5
5
3
a
b
International Academy of Orthopedic Medicine.
North American Institute of Orthopaedic Manual Therapy.
question was selected associated with hypothetical
coupling direction during active side bending initiation.
The coupling direction question consisted of a blank
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table with a set of five rows corresponding to the lumbar
segments L1–2 through L5–S1, and three sub-rows
corresponding to the postural positions of neutral,
flexion, and extension. Three columns divided all rows
outlining the choices of ‘‘opposite,’’ ‘‘same,’’ and ‘‘no
coupling.’’ The question ‘‘please identify which direction
you feel the corresponding segment will rotate at each of
the designated levels, when active left side bending is
initiated’’ was asked, allowing the participants to
conceptualise which direction coupling should theoretically occur. This allowed participants to choose the
direction of lumbar coupling rotation during active side
bending in neutral, flexion and extension, for all five
levels of the lumbar spine. Participants were asked to
place an ‘‘X’’ in the column choice marked ‘‘opposite,’’
‘‘same,’’ or ‘‘no coupling.’’ Since the data are categorical, missing values were not replaced and were
recorded as ‘‘don’t know.’’
167
coded allowing individualized association to the dependent variable. Since the dependent variable values
consist of ranks without order, the actual values taken
on by the dependent variable are irrelevant except that
larger values are assumed to correspond to probability
of changing one lower Likert choice to one ‘‘higher’’
outcome, and vice versa (Field, 2001).
Since the coupling choices were nominal/categorical,
and the sample consisted of a number of raters, a Fleiss
Kappa coefficient was used to determine agreement on
coupling direction (Uebersax, 1987; Feinstein and
Cicchetti, 1990; Portney and Watkins, 2000). According
to Fleiss (1981), values exceeding 0.75 suggest strong
agreement above chance, values in the range of 0.40 to
0.75 indicate fair levels of agreement above chance, and
values 0.40 are indicative of poor agreement above
chance levels. SAS version 8.0.1 was used in place of
SPSS, since SPSS does not have a multi-rater function
for Kappa.
2.3. Statistical analysis
Because the survey questionnaire was not a preexisting instrument, validation was necessary prior to
inference of findings. Using SPSS version 11.0.1, an
exploratory factor analysis with varimax rotation was
used to determine if the current format of survey
questions were appropriate. The exploratory factor
analysis also included the Kaiser Meyer Olin (KMO)
statistic, used to determine if the sum of partial
correlations are greater than the sum of correlations,
the Anti Image Correlation, which measures the
strength of the sum of correlations, and Bartlett’s Test
for Sphericity, a test for normalization of the sample
and the potential relationship it may yield. Eigenvalues
were extracted if greater than 0.5 a cut-off relevant for a
sample size of 200 to 300 (Field, 2001). This method
would serve to limit the latent variables to those that are
most indicative of the variance pool within the study.
The use of a factor analysis is appropriate on a sample
size of 300 or greater, and is crucial in determining if the
latent variables stand up on their own (Field, 2001).
Additionally, power for a regression analysis generally
required 10–15 respondents per question, and required a
priori sample size of 220–315.
Three separate ologit regression analyses were performed (Dependent Variable-1 importance of coupling
to their treatment, Dependent Variable-2 importance of
coupling to validation of manual therapy, Dependent
Variable-3 use of coupling during manual therapy) to
determine which independent factors were most influential to determining coupling biomechanics importance
and use. An ologit regression analysis fits ordered logit
models of an ordinal (polytomous) dependent variable
against the selected independent variables. Independent
variables can exist using any form of data; those
variables that are nominal and ordinal are dummy
3. Results
3.1. Survey questionnaire validation
The survey questionnaire did meet the power and
validation requirements for the study. The Kaiser–
Meyer–Olkin was 0.885 (0.5 and above indicates sample
adequacy) suggesting that patterns of correlations are
relatively compact so component analysis should yield
distinct and reliable factors. The Bartlett’s test for
Sphericity was significant (Pp0:0001; w2 ¼ 10; 723:1).
The Bartlett’s test indicates that the sample does include
relationships between variables, therefore component
analysis was appropriate. The survey had no questions
that required elimination after assessment of the antiimage correlation; all were above the correlation value
of 0.7. The varimax component matrix indicated four
main extractions consisting of constructs analogous to
Likert-scale questions on coupling importance of use,
validation, frequency, and use of manual therapy in the
clinic.
3.2. Descriptive findings
Eighty five point one (85.1%) percent of the
participants indicated that lumbar coupling biomechanics was ‘‘very important’’ or ‘‘important’’ in their
application of manual therapy. Only two participants
identified coupling mechanics as ‘‘definitely not important.’’ Seventy eight point eight (78.8%) percent of
participants indicated that the theory of lumbar
coupling biomechanics is ‘‘very important’’ or ‘‘important’’ in validating manual therapy. Ninety three point
two (93.2%) percent of the participants reported they
‘‘frequently’’ or ‘‘consistently’’ used lumbar coupling
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C. Cook, C. Showalter / Manual Therapy 9 (2004) 164–172
biomechanics during their application of manual therapy. Lastly, 88 percent indicated the use of manual
therapy ‘‘frequently,’’ ‘‘somewhat frequently,’’ or
‘‘sometimes’’ in the treatment of low back patients.
3.3. Inferential findings
3.3.1. First ologit regression
The model fit value for the first ologit regression was
significant (Pp0:0001; w2 ¼ 456:2). The Nagelkerke
pseudo R2 was 0.71 indicating that the goodness of fit
within this model is very good. The Nagelkerke pseudo
R2 measures the explanatory power of the model, a
similar concept to the regression coefficient in a linear
model (Long, 1997). The first ologit regression using the
dependent variable ‘‘how important the theory of lumbar
coupling biomechanics is in your application of manual
therapy’’ yielded several significant results. First, the
likelihood that one rated the theory of lumbar coupling
biomechanics toward the concept of ‘‘importance’’ was
significantly associated with their frequency of use of
coupling biomechanics in a clinical practice (Pp0:0001).
The more frequent the consideration the higher the w2 ;
indicating a higher assessment of importance. Second,
only those who felt that lumbar coupling biomechanics
was ‘‘very important’’ in validation of manual therapy,
were likely to consider the approach significant in their
application of manual therapy (P ¼ 0:001; w2 ¼ 10:28).
Third, both clinicians with a bachelors (Pp0:0001;
w2 ¼ 13:91) and a master’s degree (P ¼ 0:002;
w2 ¼ 10:02) considered lumbar coupling biomechanics
important in their application of manual therapy. The
first ologit regression results are outlined in Table 4.
3.3.2. Second ologit regression
The model fit value for the second ologit regression
was significant (Pp0:0001; w2 ¼ 537:5). The Nagelkerke
pseudo R2 was 0.687, also indicating that the goodness
of fit within this model is also very good. The second
ologit regression using the dependent variable ‘‘how
important the theory of lumbar coupling biomechanics
is in validating manual therapy’’ yielded many signifi-
cant results. First, those who ‘‘sometimes’’ (P ¼ 0:028;
w2 ¼ 4:83) or ‘‘rarely’’ (P ¼ 0:047; w2 ¼ 3:95) considered
lumbar coupling biomechanics in their application of
manual therapy did not feel lumbar coupling biomechanics was critical for validation of manual therapy.
Second, those who felt lumbar coupling biomechanics
was ‘‘very important’’ (Pp0:0001; w2 ¼ 21:1) ‘‘important’’ (P ¼ 0:004; w2 ¼ 8:18) or had ‘‘no opinion’’
(P ¼ 0:027; w2 ¼ 4:91) of lumbar coupling biomechanics
during their application of manual therapy were
significantly likely to report the necessity of validation.
Third, those with a bachelor’s (P ¼ 0:008; w2 ¼ 6:93)
and a master’s (P ¼ 0:024; w2 ¼ 5:08) level of education
did not feel lumbar coupling biomechanics was important in validating manual therapy. Those with a
doctorate degree did not achieve significance. Lastly,
those who ‘‘rarely’’ (P ¼ 0:02; w2 ¼ 4:33) used manual
therapy in their application to the spine were more likely
to report the necessity of lumbar coupling biomechanics
for the validation of manual therapy. The second ologit
regression results are presented in Table 5.
3.3.3. Third ologit regression
The model fit value for the third ologit regression was
significant (Pp0:0001; w2 ¼ 677:28). The Nagelkerke
pseudo R2 was 0.586 indicating that the goodness of fit
within this model is good. The third ologit regression
using the dependent variable ‘‘how important the theory
of lumbar coupling biomechanics is in your application
of manual therapy treatment’’ yielded few significant
results. First, those who used manual therapy ‘‘sometimes,’’
(Pp0:0001;
w2 ¼ 24:72)
‘‘consistently,’’
2
(Pp0:0001; w ¼ 19:9) and ‘‘frequently’’ (Pp0:0001;
w2 ¼ 15:8) were likely to report the consideration of
lumbar coupling biomechanics during manual therapy
treatment. Those who felt lumbar coupling biomechanics were ‘‘very important,’’ ‘‘important,’’ ‘‘somewhat
not important’’ and had ‘‘no opinion’’ in validating
manual therapy were all likely to report the consideration or use of coupling during treatment (P ¼ 0:001;
w2 ¼ 10:1). The third ologit regression results are
presented in Table 6.
Table 4
Ologit Regression 1: ‘‘How important do you feel the theory of lumbar coupling biomechanics is in your application of manual therapy?’’
Variable
B
SE
Wald w2
Coupling used during manual therapy (‘‘Frequently’’)
Coupling used during manual therapy (‘‘Consistently’’)
Coupling used during manual therapy (‘‘Sometimes’’)
Physical therapy degree (Bachelors)
Coupling used during manual therapy (‘‘Rarely’’)
Coupling important for validation (‘‘Very Important’’)
Physical therapy degree (Masters)
5.72
5.33
4.37
3.18
3.63
5.04
2.59
1.02
0.987
0.950
0.852
1.06
1.57
0.819
31.46
29.19
21.23
13.94
11.66
10.28
10.02
Indicates level of significance Pp0.05.
Indicates level of significance Pp0.0001. Only variables that were significant (Pp0.05) are reported.
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169
Table 5
Ologit Regression 2: ‘‘How important do you feel the theory of lumbar coupling biomechanics is in validating manual therapy?’’
Variable
B
SE
Wald w2
Physical therapy degree (‘‘Bachelors’’)
Use of manual therapy in back treatment (‘‘Rarely’’)
Physical therapy degree (‘‘Masters’’)
Coupling used during manual therapy (‘‘Rarely’’)
Coupling used during manual therapy (‘‘Sometimes’’)
2.28
2.02
1.91
2.01
1.95
0.867
0.885
0.850
1.03
0.888
6.93
5.23
5.08
4.83
3.95
Indicates level of significance Pp0.05. Only variables that were significant (Pp0.05) are reported.
Table 6
Ologit Regression 3: ‘‘How often do you consider or use lumbar coupling biomechanics during your manual therapy treatment?’’
Variable
B
SE
Wald w2
Use of manual therapy in back treatment (‘‘Frequently’’)
Use of manual therapy in back treatment (‘‘Consistently’’)
Use of manual therapy in back treatment (‘‘Sometimes’’)
Coupling necessary for validation (‘‘Very Important’’)
Coupling necessary for validation (‘‘Important’’)
Coupling necessary for validation (‘‘No Opinion’’)
Coupling necessary for validation (‘‘Somewhat not Important’’)
4.14
3.65
3.27
5.14
4.15
3.79
3.57
0.832
0.819
0.818
1.62
1.63
1.65
1.65
24.72
19.90
15.98
10.00
6.46
5.24
4.65
Indicates level of significance Pp0.05.
Indicates level of significance Pp0.0001. Only variables that were significant (Pp0.05) are reported.
Table 7
Inter-therapist reliability of perception of coupled motion during side
bending initiation
Spinal level
Fleiss Kappa statistic
L1–2
L2–3
L3–4
L4–5
L5–S1
0.10
0.11
0.09
0.10
0.09
Table 7 outlines the Fleiss Kappa value for each
lumbar segment. Spinal segment L1–2 was 0.10; L2–3
was 0.11; L3–4 was 0.09; L4–5 was 0.10; and L5–
S1 was 0.09. A negative Kappa means that there is less
agreement than expected by chance given the marginal
distributions of ratings.
4. Discussion
The findings of this study indicate that physiotherapists support the importance of lumbar coupling
biomechanics for practice use and validation. The
majority of the surveyed participants reported that
lumbar coupling biomechanics was important in their
application of manual therapy. A greater share also
reported that lumbar coupling biomechanics is important or very important in validating manual therapy.
Nearly all of the participants claimed they used coupling
theory at least sometimes during application of manual
therapy. Yet, it is apparent that the ‘‘directional
concept’’ associated with lumbar coupling biomechanics
is highly variable among survey participants.
The results of each Kappa statistic of each spinal level
indicates that there is wide disparity in which coupling
theory physiotherapists’ utilize during biomechanical
assessment and treatment of the lumbar spine. Regardless of level, the agreement among therapists for a preconceptual assessment of lumbar coupling motion was
poor. A negative Kappa value indicates that the
agreement among therapists is actually worse than
chance (Landis and Koch, 1977). If the clinicians truly
use the directional application of coupling, a concept
supported in this survey’s findings (93.2 percent claim
use of lumbar coupling) and by the literature (Fryette,
1954; Faye, 1984; Gertzbein et al., 1986; Plaugher, 1993;
Gracovetsky et al., 1995; Winkel et al., 1996; Lund et al.,
2002), then many clinicians are using conflicting
conceptual approaches. Since an overwhelming number
of survey participants indicate the use of lumbar
coupling for treatment, it is likely that selected directional approaches are practiced.
Significance in this study was associated with the preconceptual importance placed upon lumbar coupling
biomechanics. Frankly stated, lumbar coupling biomechanics, regardless of which directional model committed to, was used by clinicians who felt it was
important for validating and appropriately treating
patients. In all three ologit results, with the exception
of educational degree, the likelihood that one used,
reported consideration of, and felt the importance of
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lumbar coupling biomechanics for validation of manual
therapy was highly correlated. This suggests that the
direction of lumbar coupling is likely based on a
previous assumption, a previous learned model, or a
theory that plays a great deal of importance in the
application of most manual therapists, despite the fact
that physiotherapists cannot seem to agree on which
direction that theory best describes lumbar coupling.
Strangely, those therapists with both bachelor’s and
master’s levels of education reported ‘‘importance’’ of
lumbar coupling biomechanics in their application of
manual therapy, though they did not feel lumbar
coupling biomechanics was necessary in validating
manual therapy. At face value, it appears to be a
contrasting concept. There was no trend toward older or
younger, or more or less experienced clinicians stating a
preference in one coupling pattern or level of importance versus another. Other than degree, it appears any
clinician is just as likely to report the ‘‘importance’’ of
lumbar coupling theory regardless of background.
The findings of this study somewhat replicate the
findings of 3-D lumbar coupling biomechanical literature, which for several years has presented disparate
directional findings in lumbar coupling research (Schultz
et al., 1979; Pearcy and Tibrewal, 1984; McGlashen
et al., 1987; Panjabi et al., 1989; Vincenzino and
Twomey, 1993; Panjabi et al., 1994; Cholewicki et al.,
1996). Recent 3-D analyses of coupling motion support
the theory that lumbar coupling direction is unpredictable, even during analysis of nonpathological subjects.
The affect of an injury further complicates the findings
of coupled motion with recent studies reporting
variances, in both quantity and directional coupling
behaviour (Panjabi et al., 1984; Gertzbein et al., 1985,
1986; Parnianpour et al., 1988; Gracovetsky et al., 1995;
Kaigle et al., 1995, 1998; Lund et al., 2002). No studies
were found that identify a predictable, pathological
lumbar coupling pattern that correlates with a specific
pathology. The ability to predict pathological coupling
patterns during assessment would be dependent on
repeatable coupling consistency between pathological
and non-pathological subjects. To designate a motion as
abnormal spinal coupling ‘‘requires knowledge of the
normal motions’’ (Panjabi et al., 1994). Parameters of
normal spine coupling are unavailable (Harrison et al.,
1998).
The possibility exists that educational programs and
continuing education groups are teaching selective,
conflicting results from updated 3-D studies on directional-coupled motion (Cook et al., 2002). This could
account for the inconsistency of findings, specifically
associated with the poor Kappa values. Despite this
possibility, there were no backgrounds (i.e., Maitland,
McKenzie, etc.) that were significantly associated with
lumbar coupling. Though not significant (a ¼ 0:05) all
backgrounds reported a positive beta estimate, indicat-
ing an assumed importance of lumbar coupling biomechanics in the treatment, validation, and assessment of
low back patients. The data did not define one
background that placed a greater amount of importance
in lumbar coupling versus another.
This study’s findings support culminating evidence
that basing manual therapy techniques on the assumption that a single directional coupling pattern exists for
all patients is erroneous. Pertinent lumbar spine
coupling assessment appears to depend on the anatomical differences, posture and pathology of each
individual. Since many coupling movements are on the
order of 1–1.1 mm per segment this form of assessment
may not be clinically significant (Panjabi et al., 1994).
Directional coupling assessment may be beyond the
skilled practitioners’ ability to ‘‘feel’’ the finite movements (Harrison et al., 1998) and since pathologies do
not yield specific directional findings, the information
obtained may actually yield little clinical value (Panjabi
et al., 1994). Coupling motion assessment may not
provide the manual therapist with accurate or useful
information unless the pattern of coupling fits that
particular patient (Harrison et al., 1998).
4.1. Limitations of the study
The findings of this survey were drawn from
participants of one manual therapy continuing education programme. This approach does not rely heavily on
directional coupling patterns of the lumbar spine for
assessment and treatment. The possibility exists, though
unlikely according to the level of importance most
clinicians placed on coupling biomechanics, that the
participants of the course selected the manual therapy
continuing education course based on this reason.
Nearly 95 percent of the survey respondents indicated
coupling motions were important in their application of
manual therapy, a figure that does not support a nonadherence to coupling principles.
Additionally, it is likely that many of the course
participants categorized their approach on a background or discipline in which they were not versed or
skilled in. Many indicated that their approach did not
follow one specific background and selected ‘‘other.’’
The possibility exists, that one’s exposure to a particular
manual therapy model included incorrect or misinformation, thus reducing the purity of this model.
Lastly, these findings are limited to United States
clinicians; generalization to non-US clinicians is unwise.
5. Conclusion
This study found that a sample of practicing clinicians
participating in a manual therapy course place a high
level of importance on lumbar coupling biomechanics,
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C. Cook, C. Showalter / Manual Therapy 9 (2004) 164–172
but did not agree on the direction of coupled motion of
lumbar spine. The poor agreement is not indicative of
background differences, age, years of experience,
gender, or exposure to past manual therapy courses.
The importance of lumbar coupling biomechanics for
use, validation and frequency seems to be predicated on
the internal importance of lumbar coupling conceptualised by each clinician. Indeed, lumbar coupling
associated with quantity of motion for detection of
hypo and hypermobility may be beneficial. Yet, the
majority of lumbar coupling assessment methods
involve directional analysis of coupling patterns. In this
study, each clinician’s concept of lumbar coupling
direction is not consistent.
Future research should investigate whether clinicians
can accurately detect coupled motion as determined by
3-D research. Additionally, future investigation whether
coupling findings in the clinic are reflective of preconceived coupling motion is worth exploration.
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