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Journal of Electromyography and Kinesiology 8 (1998) 51–57
EMG signal amplitude assessment during abdominal bracing and
hollowing
G. T. Allison
*
, P. Godfrey, G. Robinson
1
School of Physiotherapy, Curtin University of Technology, Selby Street, Shenton Park, Western Australia 6008
Received 15 February 1996; received in revised form 8 October 1996; accepted 2 November 1996
Abstract
Motor pattern re-education is often used by clinicians as part of treatment regimens for chronic low back pain. Such programmes
are often validated by the analysis of the electromyographical (EMG) signal from specific muscles. Independent muscles are often
compared using the raw amplitude of the EMG signal or comparing the ratio of the amplitudes of two muscles. Statistical inferences
from these derived data may depend on minimizing the sources of error when manipulating the EMG signal profile data. This is
particularly true for amplitude normalization procedures, their reliability and the subsequent derivation of amplitude ratios. The
purpose of the study was first to examine the reliability of five amplitude normalized procedures and second to examine the
sensitivity of raw versus ratio amplitude comparisons during two different abdominal muscle exercises. The study demonstrated
that maximal effort amplitude normalization techniques reduce the sensitivity of raw data comparisons, but had little influence on
the sensitivity of the ratio data in differentiating the two movement patterns. It was concluded that using the EMG signal profile
to identify pathological movement strategies, in association with regional pain syndromes, needs special attention to the reliability
and validity of the derived variables. 1998 Elsevier Science Ltd. All rights reserved.
Keywords: Amplitude normalization; Movement patterns; Electromyography; Abdominal muscles; Lumbar spine
1. Introduction
Assessment of synergistic muscle function in regional
pain syndromes, such as patellofemoral pain during stair
climbing and chronic low back pain in individuals with
poor muscular stability of the lumbar spine, have been
associated with temporal and amplitude characteristics
of muscle activation profiles [3,5,8,14,15,17,18]. The
validation of these assessments has involved the use of
electromyographic (EMG) signal profiles and derived
variables. Specific EMG signal amplitudes (with and
without amplitude normalization) and amplitude ratios
between muscles have been the basis for many of the
assessment techniques [3,5,8]. The fact that reliability
and amplitude normalization techniques [1,22] may have
* Correspondence and reprint requests to Dr G. T. Allison, Curtin
University of Technology, School of Physiotherapy, Selby Street,
Shenton Park, Perth, WA 6008, Australia. Tel: +61 8 9266 3600; Fax:
+61 8 9266 3636.
1
Completed as part of the Postgraduate Diploma in Manipulative
Physiotherapy, Curtin University of Technology.
1050-6411/98/$19.00 1998 Elsevier Science Ltd. All rights reserved.
PII: S1050-6411(97)00004-7
direct influence on these derived variables raises a ques-
tion about their validity in the assessment of pathological
movement patterns.
Movement pattern strategies are a manifestation of the
interaction between cognitive, biomechanical and sen-
sory systems. Careful consideration of the techniques
employed and the use of derived variables is necessary
when using the EMG signal to validate such complex
interactions. An example in the clinical rehabilitation
setting is the use of the EMG signal of different abdomi-
nal muscles to validate movement patterns for the devel-
opment of motor control strategies as a treatment for
chronic low back pain.
Lower back pain is the single most prevalent cause for
days off work and lost productivity in many westernized
countries of the world. Segmental lumbar spine insta-
bility (hypermobility) represents a subset of individuals
with low back pain. There are passive structures which
provide stability of lumbar spinal segments at the end
of range. In mid range however, (i.e. during some daily
activities) active elements, such as the abdominal
muscles, play a significant role in the control of the spi-
52 G.T. Allison et al./Journal of Electromyography and Kinesiology 8 (1998) 51–57
nal segment. The antero-lateral abdominals (obliques
and transversus abdominis) are purported to play a sig-
nificant role in this active component of stability. Some
researchers have attempted to demonstrate optimal active
stabilization of the lumbar spine with increased muscle
activity of the antero-lateral abdominals when compared
with that of rectus abdominis [9,10,14,15,18]. Irrespec-
tive of the clinical findings, the fundamental concept of
optimization of abdominal muscle activation has been
based on comparisons between the amplitude of the
EMG signal of the antero-lateral abdominals with that
of the rectus and the ratio of the amplitude of each mus-
cle during set motor tasks.
Issues of validity and reliability need to be considered
when EMG signal temporal characteristics are to be used
in the classification of movement strategies. First, there
are well recognized sources of random and systematic
variability for the EMG signal [11,23]. Test–retest varia-
bility, for example, may be influenced by the instrumen-
tation, the methods of application of the instruments and
variance within the subjects [2,21]. The latter is signifi-
cantly influenced by adaptation of the individual
between trials, which may reflect learning or modifi-
cation of motor pattern strategies. Unless the reliability
of any assessment procedure is established, then the use
of these variables and any variables derived directly
from them, may have limited validity in the classification
of different movement strategies.
The application of EMG signal ratios, for example,
may make assumptions that the amplitude of the EMG
signal of each muscle has a similar scalar relationship
which, although standardized by some form of amplitude
normalization, may lead to errors in the manipulation of
this type of data [13]. This is not to say that ratios are
any worse than comparing the amplitude of the EMG
signal from different muscles. Indeed, various studies
indicate that the method of data reduction (i.e. the use
of ratios or EMG signal amplitudes) [3,7] influences the
sensitivity of statistical analyses in identifying differ-
ences between groups and movement patterns. In all
cases, unless the EMG signal data from muscles are
amplitude normalized then it is difficult to make ampli-
tude comparisons.
The use of a maximal effort to normalize the EMG
signal is common in the clinical literature, and has the
advantage of having a physiological meaning where the
derived data are expressed relative to the maximum. In
contrast, it is difficult to establish equivalent submaximal
loads for different muscles. This is particularly true for
the abdominal muscles. Consequently, the use of ratios
may be best combined with the use of maximal efforts
for amplitude normalization. However, maximal iso-
metric contractions are less reliable than submaximal
efforts [1,22] and are not possible in a pathological
group.
Similarly, the process of amplitude normalizing may
also influence the inferential statistics by altering the
statistical power by adding or removing variance to the
sample. It has been illustrated that amplitude normaliz-
ation techniques in the stretch shortening cycle have a
variable effect on the coefficient of variation (CV), and
that these should not be at the expense of true biological
variance [1].
The purpose of this study was threefold. First, to
examine the reliability of different amplitude normaliz-
ation and abdominal bracing and hollowing manoeuvres.
Second, to investigate the changes in muscle activity pat-
terns (raw and amplitude normalized) during abdominal
bracing and hollowing manoeuvres and finally, to inves-
tigate the influence of different amplitude normalized
temporal EMG profiles and ratios when attempting to
differentiate between two abdominal movement stra-
tegies.
2. Methods
Ten subjects, seven male and three female (aged
between 25 and 40 with a mean of 28.5 yr) were
recruited from the student body at Curtin University of
Technology, Shenton Park, and were tested within one
session. Subjects who had a current history of lower
back or abdominal pain were excluded from this study.
The study received ethical approval from the Human
Research Ethics Committee, Curtin University of Tech-
nology. All subjects gave informed consent before part-
icipating in this study.
2.1. Manoeuvres
The EMG signals from the right rectus abdominis and
right antero-lateral abdominal muscles were measured
during six specified movements. These six manoeuvres
included four normalization tasks, abdominal bracing
and abdominal hollowing. For all tasks the subject was
positioned supine with hips flexed to 45°(crook lying).
The four normalization techniques were: a resisted sit-
up with maximal isometric resistance applied through
the shoulders of the subjects (Norm 1); static double leg
lift with hips and knees at 90°(Norm 2); resisted cross
sit-up with the right shoulder moving towards the left
knee and maximal isometric resistance applied through
the right shoulder (Norm 3); and resisted side bend to
the right with maximal isometric resistance applied
through the right shoulder (Norm 4). A fifth amplitude
normalization data set (Norm 5) was also calculated
from the maximal signal amplitude for each muscle from
any of the four normalization techniques employed.
The abdominal bracing was performed with emphasis
on the coactivation of all the abdominals [12]. The hol-
lowing movement was performed with emphasis on the
antero-lateral abdominal muscle activity over the rectus
53G.T. Allison et al./Journal of Electromyography and Kinesiology 8 (1998) 51–57
abdominis [10]. This is achieved by instructing the sub-
ject to hollow their abdomen by drawing their navel up
and in towards the spine. Both of these manoeuvres were
performed crook lying with a Chattanooga pressure
biofeedback device placed under the lordosis of the lum-
bar spine to measure indirectly the force exerted by the
posterior abdominal wall. The pressure biofeedback
device is an inflatable pillow connected to a pressure
reading device and was used to standardize each
manoeuvre. The inflatable pillow pressure was initially
set at 40 mmHg while the subject was at rest. The sub-
ject was then required to increase the pressure to
50 mmHg for both the bracing and hollowing
manoeuvres and hold this level for 3 s.
2.2. Instrumentation
All testing was performed in the EMG laboratory at
the Shenton Park campus of Curtin University of Tech-
nology using surface EMG electrodes (3M Red Dot
Ag/AgCl electrodes).
The EMG signals of the right rectus abdominis and
the right antero-lateral abdominals were recorded with
Medelec PA63 pre-amplifier equipment (Medelec MS6),
connected to an AAGMk III amplifier/filter (Medelec).
The data were filtered (3 Hz and 320 Hz) and sampled
at 1000 Hz for 3 s. The total root mean squared (RMS)
was calculated for each channel and stored on disc using
a Macintosh II PC running Superscopesoftware. For
both hollowing manoeuvres ratios were calculated from
the raw and amplitude normalized data by dividing the
total RMS of the antero-lateral abdominals by the total
RMS of the rectus.
The skin resistance of the electrode sites was reduced
to less than 5 k⍀by: (a) wiping the skin with alcohol;
(b) shaving excessive body hair if necessary; (c) abrad-
ing the skin with fine grade emery paper; and (d) wiping
the skin again with alcohol [6]. Silver chloride surface
electrodes of 2 cm diameter, with an inter-electrode dis-
tance of 35 mm, were placed over the right rectus abdo-
minis (3 cm lateral to the midline and 5 cm inferior tothe
xiphoid process) and the right antero-lateral abdominals
according to techniques described by Delagi and Perotto
[4]. The earth electrode was placed over the lowest
costocartilage in the right midclavicular line.
Prior to recording the EMG signal data all subjects
practised all test manoeuvres. After at least 5 min rest
each subject performed three trials for each of the brac-
ing and hollowing manoeuvres and the four normaliz-
ation manoeuvres. The order of testing for the bracing
and hollowing manoeuvres were randomly allocated and
at least 30 s rest was given between each trial. Each
manoeuvre was assisted by an experienced physiothera-
pist. Both therapist and the subjects were blinded to the
EMG data results throughout the testing protocol.
2.3. Statistical analyses
Analyses of variance (ANOVA) with repeated meas-
ures (trials) were performed to determine the variability
between all three trials and trials two and three. Analyses
were performed on the raw data for each manoeuvre
from the muscle underlying each electrode pair, and for
the ratios derived from the data during both bracing and
hollowing manoeuvres. From the ANOVAs, intraclass
correlations (ICC) and standard error of measurement
(SEM) were calculated.
Mean, standard deviation (SD) and box plots (median,
quartiles and 10th and 90th percentiles) were calculated
for all subjects for the mean of trials two and three for
each normalizing technique and bracing and hollowing
manoeuvres.
The coefficient of variations (CV – the standard devi-
ation expressed as a percentage of the mean) were calcu-
lated for the raw, amplitude normalized and ratio data
for both bracing and hollowing manoeuvres.
Paired t-tests were performed on the total RMS EMG
signal of each muscle (antero-lateral abdominals and rec-
tus abdominis) for each bracing and hollowing abdomi-
nal manoeuvre and the ratio data. Statistical significance
was accepted at the 0.05 level of confidence.
3. Results
Table 1 shows the reliability data for the EMG signal
amplitude and the derived ratio data for all manoeuvres.
This may indicate a degree of stability in the inter-trial
motor patterns. From these data, it is clear that the ICC
and the SEM show small improvements in the reliability
(decreased variability relative to the sample and decrease
in SEM) of trials two and three when compared to the
variance in all three trials. For the maximal effort nor-
malization tasks (Norms 1, 3 and 4) high ICCs were
determined in both sets of analyses. However, the SEM
was reduced in the latter two trials when compared with
the SEM for all trials. The submaximal amplitude nor-
malization (Norm 2) showed the lowest ICC particularly
for the rectus abdominis, however trials two and three
had a much smaller SEM.
Fig. 1 illustrates the boxplot data for the amplitude
normalization manoeuvres. The fact that Norm 2 (double
leg lift) was the only submaximal task is reflected by
the lower RMS amplitudes. The box plots in Fig. 2 show
the relative distribution and total RMS of each target
muscle during the correct and incorrect hollowing
manoeuvres. The abdominal hollowing manoeuvre dis-
played a general facilitation of the activity of the antero-
lateral abdominals and a reduced range in activity of the
rectus abdominis. These results would seem to validate
the clinical classification [18] of the braced (incorrect)
54 G.T. Allison et al./Journal of Electromyography and Kinesiology 8 (1998) 51–57
Table 1
Two-trial and three-trial ICC and SEM data for the amplitude of the EMG activity for both anterolateral and rectus abdominis for the six movement
patterns and the ratio of the bracing and hollowing manoeuvres
Trials 1, 2 and 3 Trials 2 and 3
Antero-lateral Rectus Antero-lateral Rectus
ICC SEM ICC SEM ICC SEM ICC SEM
Braced 0.638 0.055 0.937 0.106 0.765 0.058 0.924 0.082
abdominals
Hollowing 0.559 0.091 0.887 0.061 0.675 0.095 0.806 0.037
abdominals
Ratio bracing* 0.871 1.368 0.992 0.946
Ratio 0.825 0.310 0.837 0.218
hollowing*
Norm 1 0.954 0.923 0.957 0.922 0.967 0.863 0.980 0.754
Norm 2 0.906 0.278 0.759 0.108 0.962 0.236 0.511 0.070
Norm 3 0.973 1.085 0.968 0.554 0.970 0.907 0.972 0.451
Norm 4 0.978 1.832 0.994 0.768 0.961 1.388 0.993 0.627
*Ratio data only.
Defined as the ratio total RMS EMG signal antero-lateral abdominals/total RMS EMG signal rectus abdominis.
and hollowing (correct) manoeuvres. The mean and stan-
dard deviations of the raw data are reported in Table 2.
Table 2 shows the significant differences in the ampli-
tude of the muscle activity between the bracing and hol-
lowing manoeuvres for the raw data and when the raw
data are normalized by each of the four normalization
techniques. It is clear that statistical differences are at
the accepted level for the raw data of the antero-lateral
abdominal muscles, and when this raw data was ampli-
tude normalized by the double leg lift data (Norm 2).
The statistical difference between the calculated ratios
for each of the bracing and hollowing manoeuvres using
the raw data and the normalized data are illustrated in
Table 3. The calculated Pvalue reflects the changes in
the statistical power of the t-test. In this case Norm 2
improves the statistical power of the analysis when com-
pared with the raw data.
Fig. 1. Boxplots of the total RMS for the antero-lateral and rectus
abdominis for all subjects performing maximal isometric contraction –
resisted sit-up (Norm 1), resisted side bending (Norm 3), resisted cross
sit-up (Norm 4) and a static submaximal hold with the hips and knees
in 90°flexion (Norm 2).
The relative changes in the CV following normaliz-
ation of the raw data are illustrated in Table 2 and Table
3. From Table 2 it would seem that irrespective of the
movement pattern only the submaximal normalization
procedure (Norm 2) reduces the variance relative to the
mean. The ratio data (Table 3) indicates that the CV is
generally reduced by all the normalization techniques
with the exception of a maximal resisted cross sit-up
(Norm 3). Norm 5, which takes the maximal amplitude
of any of the maximal isometric contractions, did not
display any significant difference in the reduction of the
CV relative to the other maximal amplitude normaliz-
ation techniques.
Fig. 2. Boxplots of the total RMS for the antero-lateral and rectus
abdominis for all subjects performing the abdominal bracing and
abdominal hollowing manoeuvres.
55G.T. Allison et al./Journal of Electromyography and Kinesiology 8 (1998) 51–57
Table 2
Differences between the amplitude of the EMG signal between the bracing and hollowing movement patterns for each muscle
Antero-lateral abdominals Rectus abdominis
Hollowing Braced Hollowing Braced
Mean SD CV Mean SD CV PMean SD CV Mean SD CV P
Raw 0.140 0.067 0.48 0.096 0.041 0.43 0.023* 0.048 0.026 0.54 0.065 0.058 0.88 0.372
Norm 1 0.375 0.248 0.66 0.291 0.174 0.60 0.106 0.116 0.139 1.20 0.138 0.124 0.90 0.579
Norm 2 0.396 0.159 0.40 0.290 0.131 0.45 0.027* 0.500 0.300 0.60 0.697 0.668 0.96 0.402
Norm 3 0.241 0.200 0.83 0.177 0.123 0.69 0.099 0.171 0.261 1.52 0.205 0.222 1.08 0.608
Norm 4 0.145 0.102 0.70 0.105 0.069 0.66 0.056 0.134 0.177 1.32 0.147 0.134 0.91 0.755
*P⬍0.05.
4. Discussion
The relative recruitment of the abdominal muscles in
this study was determined by recording the EMG signal
of the right rectus abdominis and the right antero-lateral
abdominal muscles for 10 subjects during six
manoeuvres over three trials. This information was used
to determine the reliability of each motor pattern (four
normalization tasks and two hollowing tasks) and the
validity of the reported difference between abdominal
bracing and hollowing manoeuvres.
This study demonstrated that irrespective of the mus-
cle or manoeuvre, the subjects showed slight improve-
ments in the reliability of the EMG signal profiles when
trials two and three were compared to all the trials.
Because the instrumentation and electrodes were not
removed between trials, it is postulated that these slight
improvements reflect an instability in the motor perform-
ance of the subjects attempting various manoeuvres. The
variance may be attributable to learning or the normal
variability in such motor patterns. It would seem that
inter-trial variance needs to be minimized in specific
amplitude normalization manoeuvres used to manipulate
EMG signal profiles. Both the relative variability (ICC)
and absolute variability, (SEM), need to be considered
in the acceptance of amplitude normalization procedures.
If maximal efforts are used it is possible that a high ICC
Table 3
Differences between the ratios calculated for both bracing and hollowing manoeuvres when amplitude normalized by five different techniques
Hollowing ratio Bracing ratio Meandifference tP
Mean SD CV Mean SD CV
Raw 3.32 2.00 0.60 2.33 1.78 0.76 0.99 2.733 0.0231*
Norm 1 4.34 1.85 0.43 2.86 1.69 0.59 1.47 2.488 0.0345*
Norm 2 0.87 0.30 0.34 0.61 0.34 0.56 0.26 3.002 0.0149*
Norm 3 2.20 1.50 0.68 1.70 1.40 0.82 0.50 2.450 0.0367*
Norm 4 1.46 0.63 0.43 1.05 0.64 0.61 0.41 2.694 0.0246*
Norm 5 1.69 0.88 0.52 1.23 0.81 0.66 0.46 2.601 0.0287*
All P⬍0.05.
may be obtained, yet if a submaximal motor pattern is
under investigation, then the SEM of the maximal effort
may represent a large source of error relative to the sub-
maximal signal for each individual. In general, if the
reliability (ICC and SEM) of the amplitude normaliz-
ation procedure is not established then it may not be
valid to use such techniques in the assessment of the
kinesiological adaptations of an individual’s movement
strategy.
The test–retest reliability of the rectus abdominis dur-
ing Norm 2 (double leg lift) produced very small SEM
and low ICC values. This low ICC may be attributed to
either a poor stability in the motor pattern of individual
subjects when compared with the group variance and/or
poor signal-to-noise ratio. This is plausible because dur-
ing this normalization procedure the thighs were held
vertically which may cause a variability in the function
of the rectus. Other studies have utilized a double leg
lift with the thighs at 45°of flexion and the knees at
right angles, with the feet 1 cm above the resting surface
to increase the signal-to-noise ratio and standardize the
motor pattern [14].
This study also demonstrates that there are significant
differences in the raw data for the antero-lateral abdomi-
nals during the two manoeuvres. Similarly, significant
differences in the ratio data between the manoeuvres for
both raw and normalized ratio data were demonstrated.
56 G.T. Allison et al./Journal of Electromyography and Kinesiology 8 (1998) 51–57
This supports the validation of the clinical skills used in
this study to define bracing and hollowing patterns
[14,18]. In the specific case of abdominal hollowing pat-
terns, it would seem more appropriate in the clinical
environment to monitor the recruitment (facilitation) of
the antero-lateral abdominals rather than the dissociation
of the rectus abdominis, because there is little difference
between the muscle activity of the rectus abdominis dur-
ing the two manoeuvres. However, this may not be the
case in the pathological population. Indeed, the order of
recruitment may be of critical importance in the clinical
use of EMG signal profiles in individuals with chronic
low back pain [4].
These findings also suggest that only the raw data,
when normalized by Norm 2 (double leg lift), for the
antero-lateral abdominals was statistically different
between abdominal manoeuvres. This supports the use
of sub-maximal efforts in preference to maximal efforts
in amplitude normalization procedures when assessing
differences in EMG signal profiles. Moreover, the small
SEM rather than the ICC alone should be considered
when assessing the stability of the amplitude normaliz-
ation technique. This is particularly true with small sam-
ple sizes as used in this study. Consequently, generaliza-
tions to other movement patterns and populations may
be tenuous.
Only the double leg lift amplitude normalization tech-
nique maintained the difference in the anterolateral
abdominals between the two movement patterns. There-
fore, the other normalization techniques increase the
variance relative to the effect size in the population, ther-
eby reducing the statistical power of the analysis. This
supports the inference, by Allison et al. [1], that
maximum intensity normalization techniques increase
the variance in the raw data and should be used with
careful inspection. Moreover, because these techniques
often involve individuals with lumbar spine pathology
and/or lower back pain then, it is questionable if maxi-
mal efforts are valid within this population group. If
maximal efforts are to be used in other populations, and
if the muscle is difficult to isolate (for example, trunk
muscles), then it is recommended that a battery of tasks
be used to ensure one is selected in which maximal acti-
vation is achieved.
In this study, the use of ratios appeared to be more
sensitive to the different abdominal manoeuvres irres-
pective of the normalization technique. Although the
muscles may be anatomically independent, and thereby
nullify the chances of crosstalk, there may be a signifi-
cant degree of covariance between the muscles, i.e. cen-
tral crosstalk. The use of ratios may reduce this influ-
ence. This is a possible reason why the statistical
analysis of raw amplitude data and ratio data may show
variable sensitivity in establishing differences between
movement patterns.
The level of covariance or serial dependency between
the EMG signal amplitudes of ‘independent’ muscles
may itself be a useful technique in the assessment of
different motor patterns. However, if two muscles have
a moderate degree of covariance, either by a common
central drive pattern or by crosstalk between electrodes,
then such serial dependency may increase the chance of
a type I statistical error in a subsequent ANOVA [16,20].
This degree of covariance may be a factor in the reported
variable sensitivity of using raw versus ratio data in the
assessment of motor control strategies, and should be
considered in future research protocols.
5. Conclusions
From this study it is concluded that the reliability of
any amplitude normalization technique needs to be con-
sidered using both relative (i.e. ICC) and absolute (i.e.
SEM) analyses. Careful consideration in the interpret-
ation of the EMG signal profiles of the abdominal
muscles is necessary, particularly with EMG signal
amplitude normalization of the data and the use of mus-
cle ratios in clinical interpretations. It is recommended
that appropriate normalization procedures are adopted to
suit the individual, for example, submaximal for individ-
uals with back pain. Furthermore, direct ANOVA com-
parisons of EMG signal amplitudes, irrespective of the
amplitude normalization protocol, need careful statistical
inspection if the data are associated with muscles which
are not truly independent.
Finally, the use of EMG signal profiles to identify
pathological movement strategies in association with
regional pain syndromes needs special attention to issues
of measurement. Indeed, although amplitude normaliz-
ation techniques need to be as stable as possible in absol-
ute terms (SEM), the EMG signal amplitude variability
and temporal characteristics during the performance may
provide the clinician with pertinent information about
the motor pattern.
Unlinked Ref [19]
Acknowledgements
The authors would like to acknowledge P. B. O’Sulli-
van for his assistance with the manuscript.
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Dr Garry T Allison, BEd (Hons) Sydney University, MEd The University
of Western Australia, BAppSci (Hons) Physiotherapy, PhD Curtin Univer-
sity, is a lecturer in Functional Rehabilitation at Curtin University School
of Physiotherapy. Dr Allison lectures in Sports Physiotherapy and Gradu-
ate Physiotherapy course. His research interests include: mechanisms of
fatigue and poor motor performance; motor control in pathological groups
including low back pain; and functional assessment and treatment of indi-
viduals with spinal cord injury.
Dr Allison’s professional memberships include Sports Medicine Aus-
tralia, The Sports Physiotherapy Special Interest Group, The Australian
Physiotherapy Association and The International Functional Electrical
Stimulation Society.
He is also Chairman of the Western Australian Water Polo Association
and works with the West Perth Falcons, Australian Rules Football Club.
