Scand J Med Sci Sports 2010: 20: 493–501
DOI: 10.1111/j.1600-0838.2009.00958.x
& 2009 John Wiley & Sons A/S
Clinical assessment of hip strength using a hand-held dynamometer
is reliable
K. Thorborg1, J. Petersen1, S. P. Magnusson2, P. Hölmich1
1
Department of Orthopaedic Surgery, Amager Hospital, Faculty of Health Sciences, University of Copenhagen, Copenhagen,
Denmark, 2Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
Corresponding author: Kristian Thorborg, Department of Orthopaedic Surgery, Amager Hospital, Faculty of Health Sciences,
University of Copenhagen, Italiensvej 1, Copenhagen DK-2300, Denmark. Tel: 145 32 34 32 47, Fax: 145 32 34 39 95,
E-mail: kristianthorborg@hotmail.com
Accepted for publication 18 March 2009
Hip strength assessment plays an important role in the
clinical examination of the hip and groin region. The
primary aim of this study was to examine the absolute
test–retest measurement variation concerning standardized
strength assessments of hip abduction (ABD), adduction
(ADD), external rotation (ER), internal rotation (IR),
flexion (FLEX) and extension (EXT) using a hand-held
dynamometer. Nine subjects (five males, four females),
physically active for at least 2.5 h a week, were included.
Twelve standardized isometric strength tests were performed twice with a 1-week interval in between by the
same examiner. The test order was randomized to avoid
systematic bias. Measurement variation between sessions
was 3–12%. When the maximum value of four measurements was used, test–retest measurement variation was
below 10% in 11 of the 12 individual hip strength tests
and below 5% in five of the 12 tests. No systematic
differences were present. Standardized strength assessment
procedures of hip ABD, ER, IR, FLEX, with test–retest
measurement variation below 5%, hip ADD below 6% and
hip EXT below 8%, make it possible to determine even small
changes in hip strength at the individual level.
Hip strength assessment plays an important role in
clinical examination of the hip and groin region
(Holmich et al., 2004), and clinical outcome measures
quantifying hip muscle strength are needed.
A hand-held dynamometer (HHD) is a portable
measurement device often used for assessing hip
muscle function (Tyler et al., 2001, 2006; Ireland
et al., 2003; Niemuth et al., 2005; Cichanowski et al.,
2007). The procedure is inexpensive and easy to
administer compared with traditional isokinetic testing, which makes it more suitable for the clinical
setting. Different testing procedures have been reported concerning the positioning of the persons
being tested (Krause et al., 2007; Pua et al., 2008),
and consensus on a standardized procedure to determine isometric hip muscle strength using the HHD
does not exist.
The primary aim of this study was to examine the
absolute test–retest measurement variation concerning strength assessments of hip abduction (ABD),
adduction (ADD), external rotation (ER), internal
rotation (IR), flexion (FLEX) and extension (EXT)
in healthy individuals, in 12 commonly applied testing positions.
The secondary aim of this study was to calculate
strength ratios between adductors and abductors,
and internal rotators and external rotators and
report the absolute test–retest measurement variation
of these procedures.
Materials and methods
Participants
Nine healthy participants gave their informed consent to participate in the study. Five males, mean SD, age 5 27 5 years,
height 5 184 7 cm, weight 5 80 8 kg and four females,
mean SD, age 5 25 4 years, height 5 165 8 cm, weight 5
57 7 kg. Only participants with no history of injury to the hip
and groin region were included. All participants had to be
physically active for at least 2.5 h a week. The participants did
not report any medical conditions compromising their physical
function. The participants were instructed to maintain their
regular training regimens throughout the experimental period,
but exercising on the day before the test was not allowed. The
participants had no prior HHD test experience. The Danish
ethics committee of the Capital Region, and the Danish Data
Protection Agency approved the study.
Testing set up
The testing was performed in a clinical examination room at
the Department of Orthopaedic Surgery, Amager Hospital.
The testing set up included a portable HHD and an examination table. Muscle strength was tested with the Power track II
commander (Fig. 1). The dynamometer was calibrated on each
test-day and all test procedures were standardized.
A physiotherapist (K. T.) with previous experience using
the HHD performed all the testing. All strength tests were
493
Thorborg et al.
isometric strength tests, also known as make tests (Sisto &
Dyson-Hudson, 2007). Test and retest were performed with a
1-week interval at the same time of the day. Each subject
performed FLEX, EXT, ABD, ADD, ER and IR, in two
different testing positions for each movement direction
(Table 1.)
Testing procedures
The test positions were chosen based on procedures often
applied in clinical settings (Kendall et al., 1993; Krause et al.,
2007; Pua et al., 2008). It included 12 isometric tests, which
were divided into six antagonistic pairs to avoid certain
movement directions being repeated in succession. The participants were told to stabilize themselves by holding on to the
sides of the table with their hands. The examiner applied
resistance in a fixed position and the person being tested
exerted a 5-s isometric maximum voluntary contraction
(MVC) against the dynamometer and the examiner.
The testing sequence of the six antagonistic pairs was
randomized at the initial testing session, and this testing
sequence was maintained in the same order at the retest
session. After the participants were instructed in the proce-
dures, they were asked to perform one isometric sub-maximal
contraction into the investigators’ hand, to ensure that the
correct action by the participant was performed. Then an
additional practice trial, in the form of an MVC against the
HHD, was applied. The individual test was administered four
times to reduce a possible learning effect. The highest value of
four consecutive measurements and the mean of the three
highest values are presented, because these procedures are
commonly applied in MVC testing. The highest value is
referred to hereafter as the ‘‘best’’ value.
There was a 30-s rest period between each trial, and after the
fourth and the eighth test a 5-min rest period was introduced.
These rest periods were introduced to avoid a decline in strength
across trials due to fatigue (Sisto & Dyson-Hudson, 2007). The
standardized command by the examiner was ‘‘go ahead-pushpush-push-push and relax.’’ The whole testing session took
approximately 1 h. (Detailed information on the individual
testing procedures can be found in Appendix 1.)
Calculation of strength ratio
Hip adduction/abduction strength ratios in the supine position
(HADD/HABD-SUP), and in the side-lying position (HADD/
HAB-SLP) and hip internal rotation/external rotation strength
ratio in prone position (HIR/HER-PP) and in the sitting
position (HIR/HER-SIP) were calculated based on the individual strength measurements of each movement direction.
Statistical analysis
Distributions of variables are presented as mean 1 standard
deviation (SD). The average of the test days and mean
differences from test days 1 to 2 are presented. All the
dependent variables demonstrated a normal distribution (Kolmogorov–Smirnov) and parametric tests were applied. Paired
t-tests were used to examine whether there was a systematic
difference between test and retest. Relative reliability is the
degree to which individuals maintain their position in a sample
with repeated measurements. To assess relative reliability
intra-class correlation coefficient (ICC) 2.1 coefficients (twoway random model, consistency definition) with the corresponding 95% confidence interval (95% CI) was calculated.
Absolute reliability is the degree to which repeated measurements vary for individuals, and was expressed as the standard
error p
of measurement (SEM), which was calculated as
SD 1 ICC, where SD is the SD of all scores from the
participants (Weir, 2005). SEM is also presented as a SEM%
by dividing the SEM with the average of the test and retest
values. The SEM was used for calculating the minimal
Fig. 1. Testing set-up.
Table 1. Test characteristics
Movement direction
Abbreviation
Dynamometer placement
Hip
Hip
Hip
Hip
Hip
abduction-side-lying position
abduction-supine position
adduction-side-lying position
adduction-supine position
extension-prone position-long Lever
HABD-SLP
HABD-SUP
HADD-SLP
HADD-SUP
HE-PP-LL
Hip
Hip
Hip
Hip
Hip
Hip
Hip
extension-prone position-short lever
external rotation-prone position
external rotation-sitting position
flexion-sitting position
flexion-supine position
internal rotation-prone position
internal rotation-sitting position
HE-PP-SL
HER-PP
HER-SIP
HF-SIP
HF-SUP
HIR-PP
HIR-SIP
5 cm proximal to the proximal edge of the lateral malleol
5 cm proximal to the proximal edge of the lateral malleol
5 cm proximal to the proximal edge of the medial malleol
5 cm proximal to the proximal edge of the medial malleol
5 cm proximal to the proximal edge of the medial malleol,
at the posterior calf-complex
5 cm proximal to the knee joint line, at the posterior thigh
5 cm proximal to the proximal edge of the medial malleol
5 cm proximal to the proximal edge of the medial malleol
5 cm proximal to the proximal edge of the patella border
5 cm proximal to the proximal edge of the patella border
5 cm proximal to the proximal edge of the lateral malleol
5 cm proximal to the proximal edge of the lateral malleol
494
Clinical assessment of hip strength
detectable
p change (MDC) and was calculated as SEM 1.96 2 to construct a 95% CI (Weir, 2005). A level of
Po0.05 was chosen to indicate statistical significance.
Grubb’s test was used to detect outliers in the individual
test, and these were removed (Grubbs, 1969; http://www.
graphpad.com, 2008).
Results
The reliability of individual hip strength measurements
is presented in Table 2. Measurement variation was
between 3–12% in the individual hip strength measurements. HE-PP-SL was the only test where measurement variation was above 10%. No systematic
differences were present when the best value of four
measurements was used. Systematic differences were
present in HABD-SUP, when calculating the mean of
the three best measurement repetitions.
HF-SIP (SEM 5 5%) and HF-SUP (SEM 5 5%),
HIR-PP (SEM 5 6%) and HIR-SIP (SEM 5 7–8%),
HER-PP (SEM 5 3–4%) and HER-SIP (SEM 5
4%) showed comparable measurement errors despite
the different test positions used for each movement
direction. HABD-SUP (SEM 5 3%) generally
showed less measurement variation than HABDSLP (SEM 5 9%). HE-PP-LL showed less measurement variation (SEM 5 7–8%) than HE-PP-SL
(SEM 5 11–12%). One outlier was detected for
HER-PP, when using the maximum values of four
measurements and when calculating the mean of the
Table 2. Reliability of hip strength assessment
HABD-SLP
Best of 4 reps.
(M) 3 best reps.
HABD-SUP
Best of 4 reps.
(M) 3 best reps.
HADD-SLP
Best of 4 reps.
(M) 3 best reps.
HADD-SUP
Best of 4 reps.
(M) 3 best reps.
HE-PP-LL
Best of 4 reps.
(M) 3 best reps.
HE-PP-SL
Best of 4 reps.
(M) 3 best reps.
HER-PP
Best of 4 reps.
(M) 3 best reps.
HER-SIP
Best of 4 reps.
(M) 3 best reps.
HF-SIP
Best of 4 reps.
(M) 3 best reps.
HF-SUP
Best of 4 reps.
(M) 3 best reps.
HIR-PP
Best of 4 reps.
(M) 3 best reps.
HIR-SIP
Best of 4 reps.
(M) 3 best reps.
Test (N)
mean (SD)
Retest (N)
mean (SD)
Difference test–retest
(N) mean (SD)
Paired t-test
ICC (CI 95%)
SEM
128.9 (25.0)
125.9 (24.8)
126.4 (18.6)
120.3 (19.4)
2.5 (15.8)
5.6 (15.6)
0.647
0.312
0.74 (0.21–0.94)
0.76 (0.24–9.94)
10.9
10.7
8.5
8.7
30.1
29.6
144.2 (23.2)
139.5 (23.1)
143.9 (26.4)
135.8 (26.1)
0.3 (5.8)
3.7 (4.7)
0.867
0.046*
0.97 (0.89–0.99)
0.98 (0.92–1.00)
4.2
3.4
2.9
2.5
11.6
9.4
146.2 (23.0)
141.9 (22.1)
152.6 (24.4)
145.6 (23.7)
6.3 (16.8)
3.7 (15.1)
0.290
0.488
0.75 (0.22–0.94)
0.78 (0.30–0.95)
11.6
10.5
7.8
7.3
32.1
28.9
135.1 (30.0)
130.1 (28.7)
139.0 (30.9)
134.7 (30.6)
3.9 (11.2)
4.6 (14.2)
0.329
0.359
0.93 (0.73–0.98)
0.89 (0.57–0.97)
7.8
9.6
5.7
7.2
21.6
26.5
214.1 (38.7)
207.3 (40.0)
215.4 (51.8)
209.3 (50.7)
1.3 (24.3)
2.0 (22.3)
0.873
0.795
0.86 (0.50–0.97)
0.88 (0.56–0.97)
16.6
15.3
7.7
7.4
45.9
42.4
229.4 (56.3)
218.3 (51.7)
231.8 (65.6)
218.4 (65.3)
2.3 (40.3)
0.2 (36.5)
0.866
0.988
0.78 (0.30–0.95)
0.81 (0.36–0.95)
27.8
24.9
12.1
11.4
76.8
68.9
135.5 (36.4)
130.1 (37.0)
131.6 (36.4)
127.6 (34.3)
3.9 (6.1)
2.5 (6.7)
0.116
0.329
0.99 (0.93–1.00)
0.98 (0.91–1.00)
3.5
4.9
3.0w
3.8w
9.7
13.5
129.7 (19.7)
123.7 (18.9)
131.0 (22.1)
126.0 (22.1)
1.3 (8.2)
2.3 (6.6)
0.639
0.317
0.92 (0.70–0.98)
0.95 (0.79–0.99)
5.8
4.5
4.4
3.6
16.0
12.4
270.0 (49.0)
258.8 (48.0)
278.4 (43.0)
271.2 (41.9)
8.4 (19.3)
12.4 (17.5)
0.225
0.067
0.91 (0.66–0.98)
0.92 (0.70–0.98)
13.5
12.5
4.9
4.7
37.3
34.5
212.6 (38.4)
207.5 (36.0)
222.3 (43.3)
213.5 (42.2)
9.8 (14.0)
6.0 (14.9)
0.070
0.264
0.94 (0.76–0.99)
0.93 (0.71–0.98)
9.8
10.1
4.5
4.8
27.1
27.9
117.3 (20.6)
114.1 (20.3)
121.4 (24.6)
117.4 (23.6)
4.1 (10.5)
3.4 (10.1)
0.274
0.349
0.89 (0.60–0.97)
0.89 (0.60–0.98)
7.4
7.1
6.2
6.1
20.5
19.6
135.8 (26.5)
128.0 (24.1)
138.0 (23.3)
132.4 (21.0)
2.2 (15.9)
4.4 (13.8)
0.686
0.368
0.80 (0.33–0.95)
0.81 (0.37–0.95)
10.8
9.6
7.9
7.4
29.9
26.6
SEM (%)
MDC
*Po0.05.
w
n 5 8.
M, mean; N, newton; ICC, intra-class correlation coefficient; CI, confidence interval; SEM, standard error of measurement; MDC, minimal detectable
change; SD, standard deviation; reps., repetitions; HABD-SLP, hip abduction-side-lying position; HADD-SUP, hip adduction-supine position; HE-PP-LL,
hip extension-prone position-long lever; HE-PP-SL, hip extension-prone position-short lever; HER-PP, hip external rotation-prone position; HER-SIP, hip
external rotation-sitting position; HF-SIP, hip flexion-sitting position; HF-SUP, hip flexion-supine position; HIR-PP, hip internal rotation-prone position;
HIR-SIP, hip internal rotation-sitting position.
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Thorborg et al.
Table 3. Reliability of hip antagonist strength ratios
HADD/HABD-SLP
Best of 4 reps.
(M) 3 best reps.
HAAD/HABD-SUP
Best of 4 reps.
(M) 3 best reps.
HIR/HER-PP
Best of 4 reps.
(M) 3 best reps.
HIR/HER-SIP
Best of 4 reps.
(M) 3 best reps.
Test mean
(SD)
Retest mean
(SD)
Difference
test–retest
mean (SD)
Paired
t-test
ICC (95% CI)
SEM
SEM (%)
MDC
1.16 (0.25)
1.16 (0.26)
1.22 (0.17)
1.22 (0.18)
0.05 (0.19)
0.06 (0.17)
0.423
0.308
0.63 ( 0.10–0.90)
0.69 (0.10–0.92)
0.13
0.12
10.9
10.1
0.36
0.33
0.96 (0.16)
0.94 (0.16)
1.02 (0.17)
1.00 (0.17)
0.06 (0.10)
0.06 (0.10)
0.175
0.109
0.76 (0.25–0.94)
0.81 (0.35–0.95)
0.08
0.07
7.9
7.2
0.22
0.19
0.91 (0.17)
0.88 (0.15)
0.93 (0.12)
0.92 (0.13)
0.02 (0.10)
0.04 (0.07)
0.519
0.159
0.76 (0.25–0.94)
0.72 (0.17–0.93)
0.08
0.08
7.9
8.6
0.22
0.22
1.05 (0.11)
1.04 (0.13)
1.06 (0.15)
1.06 (0.13)
0.02 (0.09)
0.02 (0.09)
0.632
0.511
0.74 (0.20–0.93)
0.76 (0.24–0.93)
0.06
0.06
5.7
5.7
0.17
0.17
*Po0.05.
M, mean; N, newton; ICC, intra-class correlation Coefficient; CI, confidence interval; SEM, standard error of measurement; MDC, minimal detectable
change; SD, standard deviation; reps., repetitions; HADD/HABD-SLP, adduction/abduction strength ratios in the side-lying position; HADD/HABD-SUP,
adduction/abduction strength ratios in the supine position; HIR/HER-PP, hip internal/hip external rotation-prone position, HIR/HER-SIP, hip internal/
hip external rotation-siting position.
three maximum values of four measurements, and
these data were removed.
The reliability of HADD/HABD strength ratios
and HIR/HER strength ratios are presented in
Table 3. Measurement variation was between 6%
and 11% for the different measurements. No systematic differences were present. HADD/HABDSLP (SEM 5 10–11%) was the only strength ratio
where measurement variation was above 10%. In
HADD/HABD-SUP (SEM 5 7–8%), HIR/HER-PP
(SEM 5 8–9%) and HIR/HER-SIP (SEM 5 6%),
measurement variation was below 10%.
Discussion
The main findings in the present study were that
standardized strength assessment procedures of hip
ABD, ADD, IR, ER, FLEX and EXT can be
performed in a clinical setting with small measurement variation. In 11 of the 12 tests, strength changes
above 10% can be considered to be ‘‘real’’ changes in
healthy individuals.
The difference in test–retest variation, when using
the best value of four consecutive measurements vs
the mean of the three best values, was insignificant
( 1%). However, systematic differences between
test and retest existed when using the mean of the
three best values. No systematic differences between
test and retest were found when the best value of four
repetitions was used, and this approach is therefore
recommended clinically.
Reliable hip muscle strength assessments make it
possible to objectively determine whether changes in
hip strength have occurred over time. Reliable hip
muscle strength assessment can also provide a screen-
496
ing tool for the detection of hip muscle weaknesses in
healthy individuals, which has been shown to be a
risk factor for sustaining a groin injury (Tyler et al.,
2001; O’Connor, 2004).
The present study is, to our knowledge, the first
study investigating the test–retest measurement variation of the hip ADD/ABD strength ratio and HIR/
HER strength ratio. The hip ADD/ABD strength
ratio was first introduced by Tyler et al. (2001). The
hip IR/ER strength ratio has not been described
previously in the literature and the present study
shows that reliable measurements of this procedure
can be obtained, both in the prone and in the sitting
position. However, the clinical relevance of the IR/
ER strength ratio and its possible implications need
to be investigated in future studies.
Direct comparison of the absolute reproducibility of
HHD vs isokinetic testing measuring hip muscle
strength has, to our knowledge, not been investigated.
Studies on the reproducibility of isokinetic testing of
the hip have shown variable relative reliability, with
ICCs ranging from 0.04 to 0.91 (Emery et al., 1999;
Claiborne et al., 2009), and these results do not seem to
indicate any superiority of this method in terms of
test–retest reliability. In a study comparing the absolute reliability of isokinetic testing vs HHD, measuring
shoulder ABD, HHD produced less test–retest measurement variation (CV 5 11%) than isokinetic testing
(CV 5 19%) (Magnusson et al., 1990). In the present
study, we found a similar measurement variation when
we tested the hip compared with when Magnusson et
al. (1990) tested the shoulder using the HHD (Magnusson et al., 1990). Thus, there seem to be no present
argument for not using the HHD in strength testing
both for clinical and research purposes when hip
strength needs to be assessed.
Clinical assessment of hip strength
Belt stabilization is often used for clinical and
for research purposes when using HHD. We deliberately avoided the use of belts or other stabilization
aids, because we wanted to make a simple testing
set up, with no extra equipment and very simple
instructions. We wanted the measurement procedures to be easy to learn, administer and implement
in the clinical setting. The self-stabilization method
where the patients hold on to the table worked well
during testing, causing no stabilization problems,
and our results suggest that this seems to be an
acceptable method.
We have only identified one study examining the
effect of different testing positions on test–retest
reliability (Krause et al., 2007). The study by Krause
et al. (2007) showed that the relative reliability of hip
ABD and ADD strength measurements in the sidelying position is better, when using a long lever
compared with a short lever. Furthermore, the relative
reliability was better when using a long lever with a
bench for stabilization in testing hip ADD, compared
with a long lever without bench stabilization (Krause
et al., 2007). Based on these results, we used the testing
position described by Krause et al. (2007). The present
study shows that testing in the supine position seems to
produce less measurement variation than in the sidelying position, when testing hip ABD and ADD
strength. A possible explanation for this could be
that stabilization issues concerning the person being
tested are completely eliminated in the supine position,
compared with the side-lying position. Direct comparisons of measurement error in the two studies, however, cannot be made because of two main reasons. (1)
We performed an isometric test, and Krause and
colleagues performed an eccentric test and (2) Krause
and colleagues only reported the relative reliability of
their measurements, which cannot be compared with
our absolute values.
Studies investigating the reproducibility of hip
strength measurement using HHD have often only
reported the relative reliability (Click et al., 2003;
Scott et al., 2004). However, relative reliability does
not provide a cut-off score for delineating a true
change from the measurement variation, which is
necessary for making valid clinical decisions. Another problem with only reporting the relative reliability is that it does not provide an insight into the
absolute reliability obtained in different studies and
with different testing procedures, making it difficult
to choose the most relevant measurement procedure
for a certain clinical problem. Therefore, the application of absolute parameters such as the SEM has
been advocated (Weir, 2005). We therefore decided
to present both the ICC and the SEM.
A limitation of the present study is that we only
investigated the intra-tester reliability, and did not
examine the inter-tester reliability. The inferior
strength of the tester is a possible factor in HHD,
affecting inter-tester reliability (Agre et al., 1987; Lu
et al., 2007; Kelln et al., 2008). Therefore, the present
study’s results can only be extrapolated to the intratester situation. However, we preferred to use a long
lever arm in the individual tests whenever possible, so
that the tester’s strength greatly exceeded the isometric force of the participant. HE-PP-SL was the
only test where measurement error was above 10%,
which could very well be because tester strength in
this measurement did not greatly exceed the isometric hip EXT force of the participant, and in
general was difficult to perform.
A second limitation is that we chose to perform
isometric testing (make-test) instead of eccentric
testing (break-test) (Sisto & Dyson-Hudson, 2007),
even though eccentric strength testing has shown
greater strength values (Bohannon, 1988). Isometric
loading induces less stress to the musculoskeletal
system than eccentric loading, which is relevant
when testing individuals presenting with pathology.
Because our long-term goal is to develop a test
suitable for both healthy individuals and individuals
presenting with hip and/or groin pathology, we
decided that a less stressful test is better suited for
this purpose.
The present study describes the absolute reliability
of 12 different hip strength measurements in a
homogenous group of healthy physically active individuals. Hip muscle strength is often affected in
patients with hip and groin pathology (Akermark &
Johansson, 1992; Holmich et al., 1999; Arokoski
et al., 2002; Cetin et al., 2004) and a simple, reliable
method of quantifying hip muscle strength in the
clinical setting is therefore needed. Physically active
individuals with hip and groin pathology must be
considered to represent a more heterogeneous group
of individuals with a potentially larger test–retest
variation, and therefore test–retest measurement variation should also be established for this group.
Hip strength assessment is an important part of the
clinical examination of the hip and groin. The present study shows that standardized strength assessment procedures of hip ABD, ER, IR and FLEX,
with test–retest measurement variation below 5%,
hip ADD below 6% and hip EXT below 8%, can be
performed in a clinical setting. The HDD is easy to
administer and produces a small measurement variation, making it possible to determine even small
changes in hip strength at the individual level.
Perspectives
Assessing hip muscle strength with an HHD shows
great promise as a reliable clinical tool for evaluating
hip strength. Furthermore, it is an inexpensive and
497
Thorborg et al.
easy method to use, making it ideal for the clinical
setting. Historically, the side-lying position for testing ABD and ADD strength has been preferred
(Kendall et al., 1993). However, clinically, the supine
position offers an advantage in the assessment of
isometric hip ABD and ADD strength using an
HDD, because it produces a smaller measurement
variation, making it capable of detecting small yet
potentially clinically meaningful changes at the individual level. The supine position also offers another
advantage, because it can be easily applied in individuals who are either unable to, or who have great
difficulties in producing sufficient force in the sidelying position to overcome gravity, due to either
muscle weakness or pain. Future studies concerning
the hip strength assessment procedures presented in
this study should be undertaken in individuals with
hip- and groin-related problems, to investigate the
applicability in this population.
Key words: hip, strength, strength ratio, measurement, rehabilitation.
Acknowledgements
This study was supported by grants from Danish Society of
Sportsphysiotherapy, Danish Regions, The Association of
Danish Physiotherapist and the Lundbeck Foundation.
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Clinical assessment of hip strength
Appendix A
Hip abduction strength, supine position (HABD-SUP)
Hip abduction strength, sidelying position (HABD-SLP)
The person being tested is in the supine position, with the hip
in neutral position. The test-leg and the resistance point are
placed over the end of the table. The opposite leg is flexed.
The person being tested holds on to the sides of the table
with both hands. The examiner applies resistance in a fixed
position and the person being tested exerts a maximum effort
against the dynamometer and the examiner. The resistance is
applied 5 cm proximal to the proximal edge of the lateral
malleol, against hip abduction. The standardised command
by the examiner is ‘‘go ahead-push-push-push-push and
relax’’ (lasting 5 s).
The person being tested is in the side-lying position, with the
hip in neutral position. The opposite hip is in 90 degrees of
hip flexion. The person being tested holds on to the side of
the table with the upper hand and rest his head on the lower
arm. The examiner stabilises the pelvis with one hand and
applies resistance in a fixed position with the other. The
person being tested exerts a maximum effort against the
dynamometer. The resistance is applied 5 cm proximal to the
proximal edge of the lateral malleol, against hip abduction.
The standardised command by the examiner is ‘‘go aheadpush-push-push-push and relax’’ (lasting 5 s).
Hip adduction strength, supine position (HADD-SUP)
Hip adduction strength, sidelying position (HADD-SLP)
The person being tested is in the supine position, with the hip
in neutral position. The test-leg and the resistance point are
placed over the end of the table. The opposite leg is flexed.
The person being tested holds on to the sides of the table
with both hands. The examiner applies resistance in a fixed
position and the person being tested exerts a maximum effort
against the dynamometer and the examiner. The resistance is
applied 5 cm proximal to the proximal edge of the medial
malleol, against hip adduction. The standardised command
by the examiner is ‘‘go ahead-push-push-push-push and
relax’’ (lasting 5 s).
The person being tested is in the side-lying position, with the
hip in neutral position. The opposite hip leg is placed on a
stool in 90 degrees of hip flexion. The person being tested
holds on to the side of the table with the upper hand and rest
the head on the lower arm. The examiner applies resistance
in a fixed position. The person being tested exerts a maximum effort against the dynamometer. The resistance is
applied 5 cm proximal to the proximal edge of the medial
malleol, against hip adduction. The standardised command
by the examiner is ‘‘go ahead-push-push-push-push and
relax’’ (lasting 5 s).
499
Thorborg et al.
Hip flexion strength, supine position (HF-SUP)
Hip flexion strength, sitting position (HF-SIP)
The person being tested in the supine position, with the hip
in 90 degrees of flexion. The person being tested holds on to
the sides of the table with both hands. The examiner applies
resistance in a fixed position and the person being tested
exerts a maximum effort against the dynamometer and the
examiner. The resistance is applied 5 cm proximal to the
proximal edge of the patella, against hip flexion. The
standardised command by the examiner is ‘‘go ahead-pushpush-push-push and relax’’ (lasting 5 s).
The person being tested is in the sitting position, with the hip
in 90 degrees of flexion. The person being tested holds on to
the sides of the table with both hands. The examiner applies
resistance in a fixed position and the person being tested
exerts a maximum effort against the dynamometer and the
examiner. The resistance is applied 5 cm proximal to the
proximal edge of the patella, against hip flexion. The
standardised command by the examiner is ‘‘go ahead-pushpush-push-push and relax’’ (lasting 5 s).
Hip extension strength, prone position, long lever
(HE-PP-LL)
Hip extension strength, prone position (HE-PP-SL)
The person being tested is in the prone position, with the hip
in the neutral position. The person being tested holds on to
the sides of the table with both hands. The examiner applies
resistance in a fixed position and the person being tested
exerts a maximum effort against the dynamometer and the
examiner. The resistance is applied 5 cm proximal to the
proximal edge of the medial malleol, at the posterior aspect
of the lower leg, against hip extension. The standardised
command by the examiner is ‘‘go ahead-push-push-pushpush and relax’’ (lasting 5 s).
The person being tested is in prone position, with the hip in
neutral position and the knee in 70–90 degrees of flexion.
The person being tested holds on to the sides of the table
with both hands. The examiner applies resistance in a fixed
position and the person being tested exerts a maximum effort
against the dynamometer and the examiner. The resistance is
applied 5 cm proximal to the knee joint line, at the posterior
aspect of the thigh, against hip extension. The standardised
command by the examiner is ‘‘go ahead-push-push-pushpush and relax’’ (lasting 5 s).
500
Clinical assessment of hip strength
Hip external rotation strength, prone position (HER-PP)
Hip external rotation strength, sitting position (HER-SIP)
The person being tested is in the prone position, with the hip
in the neutral position and with 90 degrees of flexion in the
knee. The person being tested holds on to the sides of the
table with both hands. The examiner applies resistance in a
fixed position and the person being tested exerts a maximum
effort against the dynamometer and the examiner. The
resistance is applied 5 cm proximal to the proximal edge of
the medial malleol, against hip external rotation. The
standardised command by the examiner is ‘‘go ahead-pushpush-push-push and relax’’ (lasting 5 s).
The person being tested is in the sitting position, with the hip
in 90 degrees of flexion. The person being tested holds on to
the sides of the table with both hands. The examiner applies
resistance in a fixed position and the person being tested
exerts a maximum effort against the dynamometer and the
examiner. The resistance is applied 5 cm proximal to the
proximal edge of the medial malleol, against hip external
rotation. The standardised command by the examiner is ‘‘go
ahead-push-push-push-push and relax’’ (lasting 5 s).
Hip internal rotation strength, prone position (HIR-PP)
Hip internal rotation strength, sitting position (HIR-SIP)
The person being tested is in the prone position, with the hip
in neutral position and with 90 degrees of flexion in the knee.
The person being tested holds on to the sides of the table
with both hands. The examiner applies resistance in a fixed
position and the person being tested exerts a maximum effort
against the dynamometer and the examiner. The resistance is
applied 5 cm proximal to the proximal edge of the lateral
malleol, against hip internal rotation. The standardised
command by the examiner is ‘‘go ahead-push-push-pushpush and relax’’ (lasting 5 s).
The person being tested is in the sitting position, with the hip
in 90 degrees of hip flexion. The person being tested holds on
to the sides of the table with both hands. The examiner
applies resistance in a fixed position and the person being
tested exerts a maximum effort against the dynamometer
and the examiner. The resistance is applied 5 cm proximal to
the proximal edge of the lateral malleol, against hip internal
rotation. The standardised command by the examiner is ‘‘go
ahead-push-push-push-push and relax’’ (lasting 5 s).
501