- Email: [email protected]
Intratester and intertester reproducibility of the lumbar motion monitor as a measure of range, velocity and acceleration of the thoracolumbar spine
Clinrcai
Copyright
0
Vol. I I, No. 7, 418-42 1, IVY6 Science Limited. All rights reserved Printed in Great Britain 0268-0033196 $15.00 + 0.00
Biomechunics
1996 Elscvier
ELSEVIER
PXI: !GE68-0033(%)@0031-9
K P Gill
MCSP’,
M J Callaghan
M Phil MCSP*
‘Department of Orthopaedics, Hope Hospital, Salford; Royal Liverpool University Hospital, Liverpool, UK
*Department
of Physiotherapy,
Abstract Objective. The purpose of this study was to examine the intra- and intertester reproducibility of the Lumbar Motion Monitor (LMM) as a measure of thoracolumbar range of motion (ROM), velocity and acceleration. Design, The study was a clinical trial using asymptomatic subjects. Background. The LMM is a promising device from a clinical and research perspective, though the reproducibility of it’s measurements has yet to be fully determined on subjects under free motion conditions. Methods. For intratester reproducibility, 15 subjects were required to move as far and as fast as they could in 8 s through flexion, side flexion, and rotation. They were tested on three occasions with 48 h separating tests. For intertester reproducibility, IO subjects were tested by two examiners, and were requited to move as far and as fast as they could in 8 s. Results. lntratester reproducibility coefficients ranged between 0.82 and 0.87 for ROM, 0.61 and 0.87 for velocity, and 0.46 and 0.72 for acceleration. Rotation had the poorest reprdducibility in each instance. Intertester reproducibility ranged between 0.93 and 0.98. fZonc/usions. The reproducibility of the LMM is suitably high for ROM and velocity for the device to be used for evaluation in a clinical and research setting.
Relevance The LMM is acceleration. can therefore Copyright 0 Key words: reproducibility
capable of measuring thoracolumbar spinal range of motion, velocity and Inter- and intratester reproducibility of the LMM has been established and it be used with confidence in assessinn factors associated with low back pain. 1996 Elsevier Science Ltd. Thoracolumbar
Chin, Biomech.
spine,
measurement,
Vol. 11, No. 7, 418-421,
range
01 movement,
velocity,
acceleration,
1996
Introduction
There are many different measurements and devices to quantify the loss of function and disability from low back injuries. Range of movement (RoM) is one such measure of spinal function. and there are many ways that this ma! be measured, with varying levels of reproducibility. Clinically these methods include, flexicurves. Schobtrs technique. double inclinometry, video anaiysis and computerized lumbar motion monitors. Table 1 show;I the intratester and intertester reproducibility of these methods.
The Lumbar Motion Monitor (I-MM, Chattecx Corp. USA) is an exoskeleton that replicates the 3-dimensional movement of the thoracolumbar spine. Not only are measurements of ROM achievable, but also those of velocity and acceleration. Velocity seems to be gaining importance as a measure of dysfunction. Marras and Wongsam8 in a study looking at the differences in ROM and velocity between two groups of subjects, with and without low back pain (LBP), found that the subjects with LBP had a significant reduction in their maximal velocity of movement . The LMM has been found to be accurate and extremely reliable as a measure of ROM, velocity, and acceleration when measured on a 3-dimensional reference frameY. A recent study by Marras et al.’
Gill and Callaghan:
Thoracolumbar
found the LMM to be highly reproducible for measuring ROM, velocity and acceleration, though their test procedure required subjects to remain within strict limits placed upon rotation and side flexion. The aim of this study therefore was to determine intra- and intertester reproducibility on an asymptomatic subject sample, under natural motion conditions.
spine measurement
by Lumbar
Subjects
Fifteen healthy volunteers (5 males, 10 females) participated in the study. The subjects ranged in age from 20 to 46 years and did not have any history of low back pain. Apparatus
The LMM is an exoskeleton with three wires running the length of the device. Attached to these wires are three potentiometers for each dimension of movement, tension on which causes voltage changes (at a sampling rate of 60 Hz), and hence information on position (ROM, velocity and acceleration). The LMM is attached to a 386 computer via an umbilical cable. The software used was the LMM Clinical program supplied. The LMM was calibrated between subjects. Subjects removed the clothes from their torso, and a chest harness was applied. This was aligned so that the inferior set of two sets of binding posts on the harness was aligned with the inferior angles of the scapula. The pelvic harness was applied so that the binding posts were aligned with the posterior superior iliac spines (PSIs). The LMM was attached from the inferior set of binding posts on the chest harness where possible. Intrasubject consistency was maintained with harness and exoskeleton sizes across the trials. Intratester reproducibility
protocol
Each subject stood facing the computer screen, with feet 6-8 in. apart and arms crossed, so that the hands rested on the opposite shoulders. The computer screen was not used to provide feedback to the subjects on position attained. One 8-s warm-up trial was carried out in each ROM prior to each test movement and until the examiner was satisfied that the subject understood the procedure and that there were no problems with the equipment. After a 30-s rest, each subject was instructed to move as far and as fast as possible in the 8-s trial. The test was conducted in the same order of flexion, followed by side-flexion, then rotation, for each subject. A 2-min rest was provided between trials. When performing the flexion trial, subjects were not required to limit the amount of rotation or side-bending that may have occurred naturally with flexion. Similarly these
Monitor
419
secondary motions were not controlled during the sidebending and rotation trials. The test was then repeated on two subsequent occasions, 48 h separating tests. The time of test was also standardized for each subject to reduce intrasubject variance between tests. Intertester reproducibility
Methods
Motion
protocol
Ten subjects (3 males, 7 females) participating in the above test were retested on a subsequent occasion. The set up procedure and protocol was as the above. The LMM was removed after a practice trial, through each ROM, and the subject had a 5-min rest. Subjects were then tested by two clinicians following the set-up procedure above. Between the two trials, the LMM and all harnesses were removed completely and each subject had a 5-min rest. The order of presentation was divided so that each clinician tested five people first. Instructions for rotation differed from the initial part of the experiment on intratester reliability, subjects being instructed to keep the pelvis facing the computer screen. This was to ensure spinal movement rather than movement also occurring in the lower limbs. Data analysis
Repeated-measures analysis of variance (ANOVA) and intraclass correlation coefficients were used for both intra- and intertester reproducibility. Tukey post-hoc tests were used in the intratester reproducibility part of the study to identify where significant differences occurred in the ANOVA. Results
The means, F-ratios and reproducibility coefficients for the intratester part of the study can be seen in Table 2. Table 3 shows the means, standard deviations, and reproducibility coefficients for each movement tested for the intertester part of the study. Discussion
The LMM is a measure of thoracolumbar motion from approximately T7 to S2, but due to individual variations in scapular position and spine length there will be differences in the number of spinal segments measured. Thus validity could not be established. Marras et a1.9 has looked at the accuracy of the LMM. This examined the device on a reference platform where exact angles could be established. In another study Marras et a1.7have established very high reproducibility values for all ROMS, velocities and accelerations (Table 1). Their results demonstrate higher reproducibility values than found in this study. Their test protocol required subjects to limit any secondary rotation or side-bending motion using visual feedback. In the present study these were not con-
420
Clin.
Biomech.
Vol.
11, No. 7, 1996
trolled as it was thought that secondary movements would occur naturally and consistently in individuals due to the shape of articular surfaces and recruitment patterns of various muscle groups. This may have contributed to the lower reproducibility values seen in the results presented here. In the present study subjects were required to move as fast as they could: obviously this would be difficult if limits were placed on any secondary movement that occur naturally as a subject moves. Reproducibility of the LMM can be compared favourably with other methods of testing ROM and velocity (Table 1). There were several potential sources of error in the experimental procedure: instructions used by the examiner, length of time between trials, positioning of the harness, a learning effect, and the length of practice and warm up, Instructions have been found to affect reproducibility. Matheson’” found that ‘high demand‘ instructions similar to those used in this study, achieved greater reliability though his study was on isokinetic trunk muscle testing. Wherever possible, tests/instructions should he selected based on the degree to which extraneous factors that introduce error variance can be controlJed. In this study therefore, high demand instructions are most appropriate. Depending on the nature of the study, high demand instructions may not be appropriate, such as in a patient group where further damage may result from excessive movements or velocities. ‘Time between tests may have also influenced the results. In the intratester part of the study the time between tests was 2 days, the rationale being that the tester and the subject would be unable to remember the earlier trial as well as having recovered from the exertions of the previous trial. The time gap may not have been long enough, as some subjects, especially between trials 1 and 2. complained of stiffness or tight-
Table 1. Intertester
and intratester
reproducibility
of various
measures
Measurement technique
---
Schobers’ cl 1T)c~Camp.
inc’
CA60005 Video analysis” L MM’
lntra Inter lntra Inter lntra Inter inter lntra Inter lntra lntra
lntra lntra Comp. inc. computerized intratester reproducibility;
2
75.5 (11 .O) 70.7 (10.5) 24.2 (4.3)
Vd F SB R
3
R
75.6 (8.7) 63.9 (8.8) 27.0 (6.4)
0.02 10.69 4.58
0.87 0.85 0.82
190.9 (40.5) 152.5 (31.3) 59.9f11.2)
218.7 (45.4) 158.8 (26.2) 78.5 (29.7)
223.5 (45.0) 172.2 (30.2) 79.9 (21.4)
12.91 5.04 8.75
0.87 0.81 0.61
818.5 (260) 652.6 (196) 265.7 (71)
1099.7 (246) 764.5 (170) 425.9 (172)
1139.7 (279) 845.0 (198) 448.9 (140)
21.06 10.25 15.50
0.69 0.72 0.46
ACC
F SB R
Crit F (2.28) = 3.34, P = 0.05. SB, side-bending; F, flexion;
R, rotation.
ness in the hamstring muscles. Perhaps the warm up prior to the trial should have included stretching exercises for the abdominals, gluteal muscles, hamstrings, and quadriceps to maximize ROM before testing”. Little reference has been made during ROM testing studies, but Smidt”, when discussing trunk strength testing with isokinetic dynamometers, described a learning effect that should be anticipated. Often slightly greater results are obtained on the second and subsequent tests. An increase of 13-21% may be anticipated between the measures of the first and second trials. Our results are in accordance with these findings. The fact that results tend to improve appreciably between the first and second trials will have implications for when measurements may be taken. Certainly several trials should be conducted before any measurements are taken. Positioning of the harness may also be a potential source of error. The inferior angle of the scapula was chosen as this was easily palpated and was known to lie at the level of T,. The pelvic harness was applied over the PSISs (level with S,), again being easy to locate.
of lumbar
ROM and velocity ROM
____E
R
SB
0.96-0.97 0.82-0.99 0.69-0.91 0.76 0.13-0.87 0.48 0.66 0.96 0.85-0.95 0.86 0.96
0.78-0.95 0.89-0.98 0.90-0.96 0.94-0.95 0.88
0.92-0.95 0.90-0.95
ROM F
-
0.95 0.96
E
SB
0.94 0.95
reproducibility.
References
indicated
R
0.96 0.92
inclinometry; CA6000, computerized spine motion analyser; LMM, lumbar motion monitor; Inter, intertester
F
75.3 (9.5) 63.8 (9.5) 27.7 (6.9)
- ..~ -__
D. inc. double incllnometry; bending: R. rotation: Intra,
1
ROM F SB R
0.95-0.97 0.88-0.90 0.78-0.89 0.72 0.28-0.55 0.60 0.87-0.94 0.90-0.96 0.85-0.93 0.88-0.95 0.96
Measuremen: technique
Video analysi@ LMW
Test no.
F
.---__ Flexicurve’
Table 2. Means (standard deviations), F-ratios and reproducibility coefficients for the range, velocity, and acceleration for each movement during the intratester reproducibility part of the study
by superior
figures.
F, flexion;
E, extension;
SE, side-
Gill and Callaghan: Table 3. Means (standard deviations), each range, velocity, and acceleration reproducibility part of the study
Thoracolumbar
and reproducibility coefficients recorded during the intertester
for
1
2
R
:I3 R
67.3 (9.3) 61.5i16.9) 82.5 (17.7)
67.0 (9.9) 63.3 (17.2) 79.5 (17.4)
0.93 0.96 0.95
Vel F SB R
199.7 (42.2) 184.4 (28.5) 245.4 (107.7)
195.5 (64.5) 176.6 (34.7) 227.9 (93.3)
0.93 0.93 0.98
Tesf no. ROM
Ace 1165 (307) 977 (245) 1385 1644)
E.8 R F, flexion;
SE, side-bending;
1168 (423) 944 (263) 1290 (618)
0.95 0.97 0.98
R, rotation.
The procedure followed for testing rotation may have accounted for the low measures of intratester reproducibility. Rotation was tested in standing, with free hip rotation possible. It may be that the results for rotation would be improved if the subject stood with the anterior thighs against a bed to block movement of the hips, or was sitting down so that only spinal motion was possible. As can be seen in Tables 2 and 3 the mean results for rotation are considerably larger in that part of the study examining intertester reproducibility, and is probably due to the instructions given in the two parts of the study differing. This is a good illustration of the need for consistency with instructions, though this point does not detract from the findings of this study. Conclusions
Despite the potential sources of error mentioned above, the LMM was found to have good reproducibility, especially with ROM and velocity measures. The LMM therefore can be used with confidence in a variety of settings, from research to clinical or industrial and functional, where complex 3-dimensional movements need to be analysed. Acknowledgements
Thanks go out to the staff in the Physiotherapy Department, Royal Liverpool University Hospital for their participation as subjects for this study, and to
spine measurement
by Lumbar
Motion
Monitor
421
Dr V Baltzopoulos (now at the Division of Sports Science, Crewe and Alsager Faculty, Manchester Metropolitan University) who was lecturer Biomechanics, Department of Movement Science, University of Liverpool.
References 1 Burton AK. Regional lumbar sagittal mobility; measurement by flexicurves. Clin Biomech 1986; 1: 20-6 2 Williams R, Binkley J, Bloch R et al. Reliability of the
modified-modified schober and double inclinometer methods for measuring lumbar flexion and extension. Phys Ther 1993; 73: 26-36 3 Dillard DC, Trafimow J, Andersson GBJA, Cronin K. Motion of the lumbar spine: reliability of two measurement techniques. Spine 1991; 16: 321-4 4 Newton M, Waddell G. Reliability and validity of clinical measurement of the lumbar spine in patients with chronic low back pain. Physiotherapy 1991; 77: 796-800 5 Petersen CM, Johnson RD, Schuit D. Hayes KW. Intraobserver and interobserver reliability of asymptomatic subjects‘ thoracolumbar range of motion using the OS1 CA 6000 Spine Motion Analyser. .I Orthop Sports Phys Ther 1994; 20: 207- 12 6 Robinson ME, O’Connor PD, Shirley FR, MacMillan M. Intrasubject reliability of spinal range of motion and velocity determined by video motion analysis. Phys Ther 1993; 73: 626-31 7 Marras WS, Parnianpour M, Ferguson SA et al. The classification of anatomic- and symptom-based low back disorders using motion measure models. Spine 1995: 20: 2531-46 8 Marras WS, Wongsam PE. Flexibility and velocity of the normal and impaired lumbar spine. Arch Phys Med Rehabill986; 67: 213-17 9 Marras WS, Fathallah RJ, Miller SW et al. Accuracy of a three-dimensional lumbar motion monitor for recording dynamic trunk motion characteristics. Znt J Ind Ergon 1992; 9: 75-87 10 Matheson L, Mooney V, Caiozzo Vet al. Effect of instructions on isokinetic trunk strength testing variability, reliability, absolute value, and predictive value. Spine 1992;17:914-21 11 Wiktorsson-Moller M, Oberg B, Ekstrand J, Gillquist. Effects of warming up, massage,and stretching on range of motion and muscle strength in the lower extremity. Am JSports Med 1983: 11: 249-51 12 Smidt GL, Herring T, Amundsen L. Assessment of abdominal and back extensor function: a quantitative approach and results for chronic low back pain patients. Spine 1983;8:211-13
Copyright
0
Vol. I I, No. 7, 418-42 1, IVY6 Science Limited. All rights reserved Printed in Great Britain 0268-0033196 $15.00 + 0.00
Biomechunics
1996 Elscvier
ELSEVIER
PXI: !GE68-0033(%)@0031-9
K P Gill
MCSP’,
M J Callaghan
M Phil MCSP*
‘Department of Orthopaedics, Hope Hospital, Salford; Royal Liverpool University Hospital, Liverpool, UK
*Department
of Physiotherapy,
Abstract Objective. The purpose of this study was to examine the intra- and intertester reproducibility of the Lumbar Motion Monitor (LMM) as a measure of thoracolumbar range of motion (ROM), velocity and acceleration. Design, The study was a clinical trial using asymptomatic subjects. Background. The LMM is a promising device from a clinical and research perspective, though the reproducibility of it’s measurements has yet to be fully determined on subjects under free motion conditions. Methods. For intratester reproducibility, 15 subjects were required to move as far and as fast as they could in 8 s through flexion, side flexion, and rotation. They were tested on three occasions with 48 h separating tests. For intertester reproducibility, IO subjects were tested by two examiners, and were requited to move as far and as fast as they could in 8 s. Results. lntratester reproducibility coefficients ranged between 0.82 and 0.87 for ROM, 0.61 and 0.87 for velocity, and 0.46 and 0.72 for acceleration. Rotation had the poorest reprdducibility in each instance. Intertester reproducibility ranged between 0.93 and 0.98. fZonc/usions. The reproducibility of the LMM is suitably high for ROM and velocity for the device to be used for evaluation in a clinical and research setting.
Relevance The LMM is acceleration. can therefore Copyright 0 Key words: reproducibility
capable of measuring thoracolumbar spinal range of motion, velocity and Inter- and intratester reproducibility of the LMM has been established and it be used with confidence in assessinn factors associated with low back pain. 1996 Elsevier Science Ltd. Thoracolumbar
Chin, Biomech.
spine,
measurement,
Vol. 11, No. 7, 418-421,
range
01 movement,
velocity,
acceleration,
1996
Introduction
There are many different measurements and devices to quantify the loss of function and disability from low back injuries. Range of movement (RoM) is one such measure of spinal function. and there are many ways that this ma! be measured, with varying levels of reproducibility. Clinically these methods include, flexicurves. Schobtrs technique. double inclinometry, video anaiysis and computerized lumbar motion monitors. Table 1 show;I the intratester and intertester reproducibility of these methods.
The Lumbar Motion Monitor (I-MM, Chattecx Corp. USA) is an exoskeleton that replicates the 3-dimensional movement of the thoracolumbar spine. Not only are measurements of ROM achievable, but also those of velocity and acceleration. Velocity seems to be gaining importance as a measure of dysfunction. Marras and Wongsam8 in a study looking at the differences in ROM and velocity between two groups of subjects, with and without low back pain (LBP), found that the subjects with LBP had a significant reduction in their maximal velocity of movement . The LMM has been found to be accurate and extremely reliable as a measure of ROM, velocity, and acceleration when measured on a 3-dimensional reference frameY. A recent study by Marras et al.’
Gill and Callaghan:
Thoracolumbar
found the LMM to be highly reproducible for measuring ROM, velocity and acceleration, though their test procedure required subjects to remain within strict limits placed upon rotation and side flexion. The aim of this study therefore was to determine intra- and intertester reproducibility on an asymptomatic subject sample, under natural motion conditions.
spine measurement
by Lumbar
Subjects
Fifteen healthy volunteers (5 males, 10 females) participated in the study. The subjects ranged in age from 20 to 46 years and did not have any history of low back pain. Apparatus
The LMM is an exoskeleton with three wires running the length of the device. Attached to these wires are three potentiometers for each dimension of movement, tension on which causes voltage changes (at a sampling rate of 60 Hz), and hence information on position (ROM, velocity and acceleration). The LMM is attached to a 386 computer via an umbilical cable. The software used was the LMM Clinical program supplied. The LMM was calibrated between subjects. Subjects removed the clothes from their torso, and a chest harness was applied. This was aligned so that the inferior set of two sets of binding posts on the harness was aligned with the inferior angles of the scapula. The pelvic harness was applied so that the binding posts were aligned with the posterior superior iliac spines (PSIs). The LMM was attached from the inferior set of binding posts on the chest harness where possible. Intrasubject consistency was maintained with harness and exoskeleton sizes across the trials. Intratester reproducibility
protocol
Each subject stood facing the computer screen, with feet 6-8 in. apart and arms crossed, so that the hands rested on the opposite shoulders. The computer screen was not used to provide feedback to the subjects on position attained. One 8-s warm-up trial was carried out in each ROM prior to each test movement and until the examiner was satisfied that the subject understood the procedure and that there were no problems with the equipment. After a 30-s rest, each subject was instructed to move as far and as fast as possible in the 8-s trial. The test was conducted in the same order of flexion, followed by side-flexion, then rotation, for each subject. A 2-min rest was provided between trials. When performing the flexion trial, subjects were not required to limit the amount of rotation or side-bending that may have occurred naturally with flexion. Similarly these
Monitor
419
secondary motions were not controlled during the sidebending and rotation trials. The test was then repeated on two subsequent occasions, 48 h separating tests. The time of test was also standardized for each subject to reduce intrasubject variance between tests. Intertester reproducibility
Methods
Motion
protocol
Ten subjects (3 males, 7 females) participating in the above test were retested on a subsequent occasion. The set up procedure and protocol was as the above. The LMM was removed after a practice trial, through each ROM, and the subject had a 5-min rest. Subjects were then tested by two clinicians following the set-up procedure above. Between the two trials, the LMM and all harnesses were removed completely and each subject had a 5-min rest. The order of presentation was divided so that each clinician tested five people first. Instructions for rotation differed from the initial part of the experiment on intratester reliability, subjects being instructed to keep the pelvis facing the computer screen. This was to ensure spinal movement rather than movement also occurring in the lower limbs. Data analysis
Repeated-measures analysis of variance (ANOVA) and intraclass correlation coefficients were used for both intra- and intertester reproducibility. Tukey post-hoc tests were used in the intratester reproducibility part of the study to identify where significant differences occurred in the ANOVA. Results
The means, F-ratios and reproducibility coefficients for the intratester part of the study can be seen in Table 2. Table 3 shows the means, standard deviations, and reproducibility coefficients for each movement tested for the intertester part of the study. Discussion
The LMM is a measure of thoracolumbar motion from approximately T7 to S2, but due to individual variations in scapular position and spine length there will be differences in the number of spinal segments measured. Thus validity could not be established. Marras et a1.9 has looked at the accuracy of the LMM. This examined the device on a reference platform where exact angles could be established. In another study Marras et a1.7have established very high reproducibility values for all ROMS, velocities and accelerations (Table 1). Their results demonstrate higher reproducibility values than found in this study. Their test protocol required subjects to limit any secondary rotation or side-bending motion using visual feedback. In the present study these were not con-
420
Clin.
Biomech.
Vol.
11, No. 7, 1996
trolled as it was thought that secondary movements would occur naturally and consistently in individuals due to the shape of articular surfaces and recruitment patterns of various muscle groups. This may have contributed to the lower reproducibility values seen in the results presented here. In the present study subjects were required to move as fast as they could: obviously this would be difficult if limits were placed on any secondary movement that occur naturally as a subject moves. Reproducibility of the LMM can be compared favourably with other methods of testing ROM and velocity (Table 1). There were several potential sources of error in the experimental procedure: instructions used by the examiner, length of time between trials, positioning of the harness, a learning effect, and the length of practice and warm up, Instructions have been found to affect reproducibility. Matheson’” found that ‘high demand‘ instructions similar to those used in this study, achieved greater reliability though his study was on isokinetic trunk muscle testing. Wherever possible, tests/instructions should he selected based on the degree to which extraneous factors that introduce error variance can be controlJed. In this study therefore, high demand instructions are most appropriate. Depending on the nature of the study, high demand instructions may not be appropriate, such as in a patient group where further damage may result from excessive movements or velocities. ‘Time between tests may have also influenced the results. In the intratester part of the study the time between tests was 2 days, the rationale being that the tester and the subject would be unable to remember the earlier trial as well as having recovered from the exertions of the previous trial. The time gap may not have been long enough, as some subjects, especially between trials 1 and 2. complained of stiffness or tight-
Table 1. Intertester
and intratester
reproducibility
of various
measures
Measurement technique
---
Schobers’ cl 1T)c~Camp.
inc’
CA60005 Video analysis” L MM’
lntra Inter lntra Inter lntra Inter inter lntra Inter lntra lntra
lntra lntra Comp. inc. computerized intratester reproducibility;
2
75.5 (11 .O) 70.7 (10.5) 24.2 (4.3)
Vd F SB R
3
R
75.6 (8.7) 63.9 (8.8) 27.0 (6.4)
0.02 10.69 4.58
0.87 0.85 0.82
190.9 (40.5) 152.5 (31.3) 59.9f11.2)
218.7 (45.4) 158.8 (26.2) 78.5 (29.7)
223.5 (45.0) 172.2 (30.2) 79.9 (21.4)
12.91 5.04 8.75
0.87 0.81 0.61
818.5 (260) 652.6 (196) 265.7 (71)
1099.7 (246) 764.5 (170) 425.9 (172)
1139.7 (279) 845.0 (198) 448.9 (140)
21.06 10.25 15.50
0.69 0.72 0.46
ACC
F SB R
Crit F (2.28) = 3.34, P = 0.05. SB, side-bending; F, flexion;
R, rotation.
ness in the hamstring muscles. Perhaps the warm up prior to the trial should have included stretching exercises for the abdominals, gluteal muscles, hamstrings, and quadriceps to maximize ROM before testing”. Little reference has been made during ROM testing studies, but Smidt”, when discussing trunk strength testing with isokinetic dynamometers, described a learning effect that should be anticipated. Often slightly greater results are obtained on the second and subsequent tests. An increase of 13-21% may be anticipated between the measures of the first and second trials. Our results are in accordance with these findings. The fact that results tend to improve appreciably between the first and second trials will have implications for when measurements may be taken. Certainly several trials should be conducted before any measurements are taken. Positioning of the harness may also be a potential source of error. The inferior angle of the scapula was chosen as this was easily palpated and was known to lie at the level of T,. The pelvic harness was applied over the PSISs (level with S,), again being easy to locate.
of lumbar
ROM and velocity ROM
____E
R
SB
0.96-0.97 0.82-0.99 0.69-0.91 0.76 0.13-0.87 0.48 0.66 0.96 0.85-0.95 0.86 0.96
0.78-0.95 0.89-0.98 0.90-0.96 0.94-0.95 0.88
0.92-0.95 0.90-0.95
ROM F
-
0.95 0.96
E
SB
0.94 0.95
reproducibility.
References
indicated
R
0.96 0.92
inclinometry; CA6000, computerized spine motion analyser; LMM, lumbar motion monitor; Inter, intertester
F
75.3 (9.5) 63.8 (9.5) 27.7 (6.9)
- ..~ -__
D. inc. double incllnometry; bending: R. rotation: Intra,
1
ROM F SB R
0.95-0.97 0.88-0.90 0.78-0.89 0.72 0.28-0.55 0.60 0.87-0.94 0.90-0.96 0.85-0.93 0.88-0.95 0.96
Measuremen: technique
Video analysi@ LMW
Test no.
F
.---__ Flexicurve’
Table 2. Means (standard deviations), F-ratios and reproducibility coefficients for the range, velocity, and acceleration for each movement during the intratester reproducibility part of the study
by superior
figures.
F, flexion;
E, extension;
SE, side-
Gill and Callaghan: Table 3. Means (standard deviations), each range, velocity, and acceleration reproducibility part of the study
Thoracolumbar
and reproducibility coefficients recorded during the intertester
for
1
2
R
:I3 R
67.3 (9.3) 61.5i16.9) 82.5 (17.7)
67.0 (9.9) 63.3 (17.2) 79.5 (17.4)
0.93 0.96 0.95
Vel F SB R
199.7 (42.2) 184.4 (28.5) 245.4 (107.7)
195.5 (64.5) 176.6 (34.7) 227.9 (93.3)
0.93 0.93 0.98
Tesf no. ROM
Ace 1165 (307) 977 (245) 1385 1644)
E.8 R F, flexion;
SE, side-bending;
1168 (423) 944 (263) 1290 (618)
0.95 0.97 0.98
R, rotation.
The procedure followed for testing rotation may have accounted for the low measures of intratester reproducibility. Rotation was tested in standing, with free hip rotation possible. It may be that the results for rotation would be improved if the subject stood with the anterior thighs against a bed to block movement of the hips, or was sitting down so that only spinal motion was possible. As can be seen in Tables 2 and 3 the mean results for rotation are considerably larger in that part of the study examining intertester reproducibility, and is probably due to the instructions given in the two parts of the study differing. This is a good illustration of the need for consistency with instructions, though this point does not detract from the findings of this study. Conclusions
Despite the potential sources of error mentioned above, the LMM was found to have good reproducibility, especially with ROM and velocity measures. The LMM therefore can be used with confidence in a variety of settings, from research to clinical or industrial and functional, where complex 3-dimensional movements need to be analysed. Acknowledgements
Thanks go out to the staff in the Physiotherapy Department, Royal Liverpool University Hospital for their participation as subjects for this study, and to
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Dr V Baltzopoulos (now at the Division of Sports Science, Crewe and Alsager Faculty, Manchester Metropolitan University) who was lecturer Biomechanics, Department of Movement Science, University of Liverpool.
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