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BioMed Central
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BMC Geriatrics
Open Access
Research article
Are non-slip socks really 'non-slip'? An analysis of slip resistance
Satyan Chari*†1,2, Terrence Haines†3,4,5, Paul Varghese6 and
Alyssia Economidis7
Address: 1Safety and Quality Unit, Royal Brisbane and Women's Hospital, Queensland Health, Queensland 4029, Australia, 2Faculty of Medicine,
Nursing and Health Sciences, Monash University, Victoria 3800, Australia, 3Clinical Research, Southern Physiotherapy School, Monash University,
Victoria 3168, Australia, 4School of Health and Rehabilitation Sciences, The University of Queensland, Queensland 4072, Australia, 5Allied Health
Research Unit, Kingston Centre, Southern Health, Victoria 3192, Australia, 6Geriatric Medicine, Geriatric and Rehabilitation Unit (GARU), Princess
Alexandra Hospital, Queensland Health, Queensland 4102, Australia and 7Early Assessment and Medical Unit, Internal Medicine Services, The
Prince Charles Hospital, Queensland Health, Queensland 4032, Australia
Email: Satyan Chari* - srcha5@student.monash.edu.au; Terrence Haines - terrence.haines@med.monash.edu.au;
Paul Varghese - paul_varghese@health.qld.gov.au; Alyssia Economidis - alyssia_economidis@health.qld.gov.au
* Corresponding author †Equal contributors
Abstract
Background: Non-slip socks have been suggested as a means of preventing accidental falls due to slips.
This study compared the relative slip resistance of commercially available non-slip socks with other foot
conditions, namely bare feet, compression stockings and conventional socks, in order to determine any
traction benefit.
Methods: Phase one involved slip resistance testing of two commercially available non-slip socks and one
compression-stocking sample through an independent blinded materials testing laboratory using a Wet
Pendulum Test.
Phase two of the study involved in-situ testing among healthy adult subjects (n = 3). Subjects stood
unsupported on a variable angle, inclined platform topped with hospital grade vinyl, in a range of foot
conditions (bare feet, non-slip socks, conventional socks and compression stockings). Inclination was
increased incrementally for each condition until slippage of any magnitude was detected. The platform
angle was monitored using a spatial orientation tracking sensor and slippage point was recorded on video.
Results: Phase one results generated through Wet Pendulum Test suggested that non-slip socks did not
offer better traction than compression stockings. However, in phase two, slippage in compression
stockings was detected at the lowest angles across all participants. Amongst the foot conditions tested,
barefoot conditions produced the highest slip angles for all participants indicating that this foot condition
provided the highest slip resistance.
Conclusion: It is evident that bare feet provide better slip resistance than non-slip socks and therefore
might represent a safer foot condition. This study did not explore whether traction provided by bare feet
was comparable to 'optimal' footwear such as shoes. However, previous studies have associated barefoot
mobilisation with increased falls. Therefore, it is suggested that all patients continue to be encouraged to
mobilise in appropriate, well-fitting shoes whilst in hospital. Limitations of this study in relation to the
testing method, participant group and sample size are discussed.
Published: 25 August 2009
BMC Geriatrics 2009, 9:39 doi:10.1186/1471-2318-9-39
Received: 19 February 2009
Accepted: 25 August 2009
This article is available from: http://www.biomedcentral.com/1471-2318/9/39
© 2009 Chari et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
BMC Geriatrics 2009, 9:39 http://www.biomedcentral.com/1471-2318/9/39
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Background
Falls continue to remain among the highest reported
causes of unintended harm to elderly patients in hospital
[1]. Several multifactorial interventions to prevent falls in
hospitals have been investigated, and some have demon-
strated effectiveness [2-5]. However, few have focussed on
the role of footwear in the prevention of in-hospital falls.
The 2005 Australian Falls Prevention Guidelines (Prevent-
ing Falls and Harm from Falls among Older People) rec-
ommend that patients wear well fitting, closed shoes with
a flat heel while in hospital [6]. However, ensuring com-
pliance with this recommendation is sometimes difficult
due to patient cognitive impairment (confusion, delir-
ium, dementia), lack of access to appropriate footwear,
intentional non-compliance and other factors.
Concurrently, there has been a growing recognition of
hospital morbidity and mortality due to venous-throm-
boembolism (VTE) [7]. The Australian and New Zealand
Working Party on the Management and Prevention of
Venous Thromboembolism suggest consideration of grad-
uated compression stockings as an adjunct to pharmaco-
logical prophylaxis, in the management of patients at risk
of VTE [8].
As patients can tend to mobilise without footwear while
in hospital, there has been concern among clinicians that
patients might be at an increased risk of falling due to the
'slippery' texture of most compression stocking products.
As a result, the use of 'non-slip' socks over compression
stockings has gained popularity as a strategy to improve
under-foot traction. Non-slip socks (also referred to as
anti-skid or treaded socks) are socks with a tread pattern
provided on the sole, or ventral surface, for the purpose of
improving traction. These socks appear to be a logical
solution, however there is limited evidence regarding their
effectiveness in improving traction and more importantly,
their impact on patient safety.
One retrospective study evaluated falls rates for a 102 day
period before and after implementation of a non-slip sock
(treaded sock) intervention in a Special Care Unit at a
nursing home [9]. In total, twenty one falls were recorded
in 102 days prior to intervention and eighteen falls were
recorded in the 102 days after intervention; a modest
change that was not statistically significant. An eight-fold
reduction in falls due to slips on urine was reported by the
authors, who attributed this positive finding to the
treaded sock intervention. However, there was a concur-
rent five-fold increase in falls where patients were 'found
on the floor', which suggests that the intervention had lit-
tle positive effect overall and that modified reporting
might have been a factor as staff were not blinded to the
intervention period.
This study aimed to establish the slip-resistance of non-
slip socks relative to other foot conditions commonly
encountered in hospital, in order to determine any trac-
tion benefit. Additionally, the data generated through this
study would help inform decisions on further clinical
research on non-slip socks as a falls prevention strategy.
Methods
Design
Ethics approval was sought and gained from the Princess
Alexandra Hospital Human Research Ethics Committee. A
two-phase study was designed. In phase one, two com-
mercially available non-slip socks and one brand of com-
pression stockings were tested for slip resistance through
a blinded, independent materials testing laboratory
(Commonwealth Scientific and Industrial Research
Organisation's Manufacturing and Materials Technology
Laboratory in Victoria). The samples were tested using a
Pendulum Friction Test, also referred to as the Wet Pendu-
lum Test [10,11]. The Wet Pendulum Test was selected
instead of the alternative Inclined Ramp Test described in
AS/NZS 4586:2004 [10], as it provides a continuous
(rather than ordinal) measure, and is therefore more sen-
sitive to small differences in slip resistance. Phase two
involved in-situ testing of slip resistance of non-slip socks
and other foot conditions among healthy adults. Phase
two testing was analogous to the Inclined Ramp Test pre-
scribed by the Australian Standard [10]. However, the
method of testing followed in phase two, arguably pro-
vides a better approximation of standard hospital flooring
in a dry state whilst also allowing for a continuous meas-
ure of slip resistance.
Phase One
The Wet Pendulum Test was carried out at the Common-
wealth Scientific and Industrial Research Organisation's
(CSIRO) Materials, Surfaces and Finishes laboratory at
Highett, Victoria. The testers were blinded to brand and
manufacturer details of samples provided (all tags and
identifiers removed), but not to product function. Sam-
ples were labelled A (compression stocking), B and C
(non-slip socks) respectively.
Apparatus and Procedure
The Wet Pendulum Test was completed in accordance
with AS/NZS 4586:2004 [10] using a calibrated Munro-
Stanley Pendulum Friction Tester. The Wet Pendulum Test
is a test designed to simulate the mechanics of a person
slipping on a wet surface. The terminal end of the pendu-
lum arm has a mechanical foot with a spring-loaded rub-
ber slider attached, to simulate the heel of the foot (Figure
1). The floor surface is saturated with deionised water
prior to testing to simulate the presence of a fluid contam-
inant. The test is set up with the apparatus level to the
floor and the length of the pendulum arm adjusted such
BMC Geriatrics 2009, 9:39 http://www.biomedcentral.com/1471-2318/9/39
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that the rubber slider 'kicks' through when released, con-
tacting the floor surface momentarily. On 'kicking'
through, a loss of momentum occurs due to the friction
generated at the point of contact. The amount of friction
is dependant on the slip resistance characteristics of the
floor and 'heel' surfaces. This loss in momentum causes a
proportionate reduction in the arc described by the pen-
dulum which is measured on an inverse scale affixed to
the tester. The scale provides a British Pendulum Number
(BPN) which is the unit of measurement for this test. A
higher BPN indicates higher slip resistance. A detailed
description of the Pendulum Friction Testing protocol is
available as an appendix to the AS/NZS 4586:2004 [10].
The Wet Pendulum Test is normally used to test different
floor surfaces for slip resistance while the rubber slider is
conditioned before testing to provide a constant slip
resistance. However, for the purpose of this study the con-
ditions were reversed, by keeping the floor surface con-
stant (2.0 mm thickness hospital graded vinyl) and
varying 'foot' conditions by draping the test samples over
the slider. Samples were adhered to the rubber slider using
double-sided adhesive tape to eliminate bunching of the
material on contact. Five different specimens cut from the
ventral surface of the samples were tested three times
each, producing fifteen readings per sample. Testing was
performed at an ambient temperature of 23°C (prescribed
testing temperature range).
Phase Two
Phase two of the study was conducted at the Princess Alex-
andra Hospital's Physiotherapy Gait Laboratory. A con-
venience sample of three brands of non-slip socks were
tested (Figure 2). All of the non-slip sock products tested
are commercially available in Australia and marketed for
use with hospital patients. The non-slip socks brands
tested in phase one (samples B and C) were included in
phase two. An additional non-slip sock product was
included in phase two as the investigators only became
aware of the existence of this product following the com-
pletion of phase one.
Additional foot conditions tested in phase two were con-
ventional socks (worn by the participants on the day of
testing), bare feet and a compression stocking product
currently used by facilities in Queensland Health (also
tested in phase one).
Two male (Participant B and C) and one female partici-
pant (Participant A) were included in phase two of this
study. Written informed consent was secured from partic-
ipants prior to commencement. Participant A was 173 cm
in height, weighed 65 kg and wore Australian size 8
women's footwear. Participant B was 182 cm in height,
weighed 105 kg and wore Australian size 11.5 men's foot-
wear. Participant C was 186 cm in height, weighed 85 kg
and wore Australian size 12 men's footwear. All partici-
pants were aged between 29 and 31 years on the day of
testing.
Apparatus and Procedure
The surface of the ramp was constructed by mounting a
900 mm × 600 mm panel of 2.0 mm thickness hospital
grade vinyl (AS/NZS 2055.1:1985) [12], on to a rigid
wooden board as per manufacturer's instructions. The
ramp was bracketed on one end and the angle of inclina-
tion was adjusted by shifting support blocks forwards or
backwards. The ramp was positioned in between a set of
Phase one testing apparatus: Wet Pendulum TestFigure 1
Phase one testing apparatus: Wet Pendulum Test.
pendulum arm
rubber slider (wit h
specimen sample
att ached)
mechanical
‘foot ’
scale
Point of contact
(with w nant)ater contami
Non-slip sock samplesFigure 2
Non-slip sock samples.
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mobile parallel bars (Figure 3). An Intersense Interi-
aCube® inertial orientation reference system was used to
accurately measure the inclination of the ramp. The sen-
sor was taped to the surface of the ramp such that the
'pitch' reading provided the angle of inclination. Data was
monitored on a laptop in real time. The testing procedure
was recorded on video to enable verification of manually
collected data prior to transcription to a spreadsheet for
analysis.
Once the angle of inclination was set (with an error toler-
ance of 0.2°), participants were asked to stand on the
ramp and attempt to maintain an erect posture unsup-
ported for a minimum of three seconds. If successful, the
angle of the ramp was increased in one degree increments
and the test was repeated until a slippage point was noted.
Once slippage occurred, testing of that particular foot con-
dition for the participant was complete. This procedure
was repeated for every foot condition with each partici-
pant (non-slip socks, compression stockings, bare feet,
and standard socks). Where multiple sizes of a non-slip
sock product were available, these were also tested. The
ramp surface was wiped down periodically to reduce con-
taminant build-up during testing.
Results
Phase one
The compression stocking sample achieved the highest
mean British Pendulum Number (55) followed by the
two non slip sock samples B (40) and C (26), indicating
that the compression stocking demonstrated the highest
slip resistance in this testing condition (Figure 4). There
was little variation in results from the five different areas
of sole tested.
Phase two
Results of phase two testing demonstrated a relatively
consistent slippage pattern across all three participants
(Figure 5). However, in contrast to the Wet Pendulum Test
in phase one, all participants slipped at the lowest angles
while wearing compression stockings (12°,11° and11°
respectively). Performance in conventional socks was rel-
atively better, with slippage at 18°, 17° and 16° respec-
tively. Performance in non-slip socks was variable, with
slippage occurring in some products at angles comparable
to conventional socks. Other non-slip socks performed
better with traction maintained up to 30° in the case of
one participant for a specific size of a non-slip sock brand.
Different sizes within the same product also varied in per-
formance (slippage at 19° for the 'small' sized sock and
30° for the 'medium' sized sock of the same brand in one
participant). Barefoot conditions consistently resulted in
the highest levels of traction across all participants with
slippage at 38°, 27° and 30° respectively.
Discussion
Previous studies have associated mobilisation in foot con-
ditions other than shoes (such as slippers, sandals, socks,
bare-feet and other 'non-ideal' foot conditions) with an
increased risk of falling [13-15]. The poorer relative per-
formance of non-slip socks compared to barefoot condi-
Phase one testing apparatus: Inclined Ramp TestFigure 3
Phase one testing apparatus: Inclined Ramp Test.
Phase one wet pendulum test resultsFigure 4
Phase one wet pendulum test results.
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5
Bri tish P endulum Number (BPN)
Sample A – Com pression Stocking
Sam
p
le B
–
Traction Socks
®
Sam
p
le C
–
Gri
p
sox
®
Phase two test results: slippage pointsFigure 5
Phase two test results: slippage points.
11
18 17 17
21 22
19
30
38
12
17 18
21
17
19 18
25
27
11
15
18 19 18 19 18
26
30
0
10
20
30
40
50
Compression
Stockings
Conventional
Socks
Traction
Socks®
Green
Traction
Socks® Blue
Jobst Socks®
S-M
Jobst Socks®
M-L
Gripsox®
Small
Gripsox®
Medium
Barefoot
Angle in Degrees
Participant A
Participant B
Participant C
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tions (a 'non-ideal' foot condition) in our study suggest
that non-slip socks do not represent an adequate alterna-
tive to well-fitting rubber soled footwear or even to mobi-
lisation in bare feet.
Additionally, ensuring that non-slip socks are being worn
appropriately (with tread pattern aligned with the sole of
the foot) would most likely require periodic checks by
clinical staff, especially if provided to patients with cogni-
tive impairment. Aside from the resource implications,
poorly fitted socks or socks that are mis-aligned could
constitute a trip or slip hazard for patients. It is suggested
that these risks might outweigh the clinical benefits of
marginally improved underfoot traction over compres-
sion stockings.
All non-slip sock products tested in this study had a tread
pattern on the ventral surface (sole) of the sock (Figure 2).
This tread pattern is three-dimensional in nature resulting
in a series of peaks (1–2 mm high) and troughs. In phase
one, specimens cut from the three samples were adhered
to the rubber slider using double sided tape. As the Wet
Pendulum Test generates limited downward force during
the 'kick' phase of the test, force at the point of contact is
predominantly along the horizontal plane. As a result, the
rubber slider does not press down on the troughs. Conse-
quently, only the raised portion of the sock specimen
would make contact with the floor, reducing what could
be termed as the 'effective contact area' and therefore
reducing slip resistance. This phenomenon is avoided in
the compression stocking sample due to the absence of a
tread pattern resulting in a level surface. In this case, the
effective contact area would be equal to the size of the
specimen adhered to the rubber slider.
When tested in-situ during phase two, the combined effect
of participant weight and pliant characteristics of soft tis-
sue of the foot are likely to force contact between the
troughs of the non-slip sock and the floor thereby ensur-
ing contact is made between the whole foot and floor
across all testing conditions. This difference is proposed a
plausible explanation for the apparent lack of congruence
between phase one and phase two results.
Nagata, Watanabe, Inoue and Kim (2008) studied the
validity of five different friction testing methods as an
index of the risk of slipping with seventy subjects and con-
cluded that of the five methods tested, the ramp test was
the most reliable, and the pendulum tester the least relia-
ble [16]. These results appear to validate the incongruence
between results of two phases of our study.
There is also a possibility that the relative performance of
non-slip socks and compression stocking is altered in the
presence of a fluid contaminant. This hypothesis would
require further investigation and if verifiable, has poten-
tial clinical implications when using non-slip socks with
older persons having issues with bladder continence.
Given previous findings that slips associated with stand-
ing in urine were reduced amongst nursing home resi-
dents wearing non-slip socks, one would have expected
these socks to display greater slip resistance in the Wet
Pendulum Test condition. However, this was not the case.
Limitations
This study tested a convenience sample of non-slip socks,
however it is recognised that there may be alternative
products which perform differently.
This study tested non-slip sock performance on hospital
grade vinyl which is the preferred floor covering as per AS
2055.1 [12]. However, it is possible that relative results
might vary over other surfaces such as tile, polished con-
crete or carpet. Foot anatomy, biomechanics and skin
characteristics of the relatively young and healthy partici-
pants in this study are also likely to be different to hospital
patients who are older and frail. Some variation in per-
formance across foot conditions could be expected with a
sample of older hospital patients.
The testing protocol employed in phase two, although not
standardised or previously validated, is very similar in
method to the ramp test recommended in the Australian
Standard [10]. However, the testing protocol still provides
a reliable method to compare performance of various foot
conditions within the same participant.
It needs to be acknowledged that the phase two ramp test
collected slippage data with participants in a static stand-
ing position. It is conceivable that slippage characteristics,
and therefore performance, of these foot conditions might
vary during dynamic walking on a level surface.
The small number of participants can be considered a lim-
itation of this study. However, we would like to highlight
that the unit of analysis is not the individual participant
but rather the results of the test in each foot condition,
which is a product of the unique characteristics of the con-
tact material (compression stocking, non-slip sock, con-
ventional sock or skin), the fit of the particular sock (or
compression stocking sample) to the participant's feet,
and the weight of the participant. Additionally, we tested
subjects with both large and small feet, as well as signifi-
cant difference in weight, and found the results to follow
a consistent pattern across all participants.
Conclusion
Non-slip socks demonstrated poorer slip resistance than
bare feet. It is therefore suggested that patients would be
more likely to slip whilst mobilising in non-slip socks
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BMC Geriatrics 2009, 9:39 http://www.biomedcentral.com/1471-2318/9/39
Page 6 of 6
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compared to bare feet. Non-slip socks offer marginal ben-
efit in slip-resistance over compression stockings in dry
conditions, however slip resistance of such products in the
presence of fluid contaminants needs to be explored fur-
ther. This study did not explore whether traction provided
by bare feet was comparable to 'optimal' footwear such as
shoes. However, previous studies have associated barefoot
mobilisation with increased falls. It is therefore suggested
that all patients continue to be encouraged to mobilise in
appropriate, well-fitting shoes whilst in hospital.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
SC, TH, PV contributed to the development, conceptuali-
zation and design of the study. TH, SC and AE were
responsible data collection and the conduct of Phase 2
testing. SC was responsible for data transcription, analy-
sis, and preparation of the manuscript. TH supervised the
data collection and provided assistance with data analyses
and editing the final manuscript. All authors contributed
to interpretation of results and read and approved the
final draft of the manuscript.
Acknowledgements
The authors would like to thank the Queensland Falls Injury Prevention
Collaborative for approving this study and the Queensland Health Patient
Safety Centre for funding phase 1 testing through an external research lab-
oratory. The authors would also like to thank the Princess Alexandra Hos-
pital Geriatric Assessment and Rehabilitation Unit (GARU) for allowing the
use of the physiotherapy gait laboratory facilities. The authors acknowledge
the invaluable support received from Princess Alexandra Hospital physio-
therapy research and clinical staff towards setting up the testing environ-
ment.
SC would like to specifically thank the Royal Brisbane and Women's Hos-
pital Safety and Quality Unit for the support, resources and off-line time
which enabled completion of this study.
None of the investigators received any financial support related to the
research in this paper. The research was investigator initiated and not spon-
sored by any company.
References
1. Nadkarni JB, Iyengar KP, Dussa C, Watwe S, Vishwanath K: Ortho-
paedic injuries following falls by hospital in-patients. Gerontol-
ogy 2005, 51(5):329-333.
2. Haines TP, Bennell KL, Osborne RH, Hill KD: Effectiveness of tar-
geted falls prevention programme in subacute hospital set-
ting: randomised controlled trial. BMJ 2004, 328(7441):676.
3. Fonda D, Cook J, Sandler V, Bailey M: Sustained reduction in seri-
ous fall-related injuries in older people in hospital. Medical
Journal of Australia 2006, 184:379-382.
4. Stenvall M, Olofsson B, Lundström M, Englund U, Borssén B, Svensson
O, Nyberg L, Gustafson Y: A multidisciplinary, multifactorial
intervention program reduces postoperative falls and inju-
ries after femoral neck fracture. Osteoporosis International 2007,
18(2):167-75.
5. Healey F, Monro A, Cockram A, Adams V, Heseltine D: Using tar-
geted risk factor reduction to prevent falls in older in-
patients: a randomised controlled trial. Age Ageing 2004,
33(4):390-395.
6. Australian Safety and Quality Commission: Preventing falls and
harm from falls in older people. Best practice guidelines for
Australian hospitals and residential aged care facilities. Aus-
tralian Council for Safety and Quality in Healthcare; 2005.
7. Access Economics: The burden of venous thromboembolism in
Australia. Report for the Australia and New Zealand work-
ing party on the management and prevention of venous
thromboembolism. Australian Institute of Health and Welfare;
2008.
8. Australia & New Zealand Working Party on the Management and Pre-
vention of Venous Thromboembolism: Prevention of Venous
Thromboembolism: Best Practice Guidelines for Australia &
New Zealand. 4th edition. Health Education & Management Inno-
vations; 2007.
9. Meddaugh DI, Friedenberg DL, Knisley R: Special socks for special
people: Falls in special care units: All persons involved with
making a safe environment for residents in SCUs must con-
tinue to find ways to minimize the risk of falls. Here is one
simple, effective method. Geriatric Nursing 1996, 17(1):24-26.
10. Standards Australia: Slip resistance classifications of new pedes-
trian surface materials AS/NZS 4586:2004. Standards Aus-
tralia; 2004.
11. Standards Australia: Slip resistance classification of existing
pedestrian surface materials As/NZS 4633:2004. Standards
Australia; 2004.
12. Standards Australia: AS 2055.1:1985: PVC sheet floor-covering
– Unbacked, flexible. Standards Australia; 1985.
13. Koepsell TD, Wolf ME, Buchner DM, Kukull WA, LaCroix AZ,
Tencer AF, Frankenfeld CL, Tautvydas M, Larson EB: Footwear
style and risk of falls in older adults. Journal Of The American Ger-
iatrics Society 2004, 52(9):1495-1501.
14. Menz HB, Morris ME, Lord SR: Footwear characteristics and risk
of indoor and outdoor falls in older people. Gerontology 2006,
52(3):174-180.
15. Sherrington C, Menz HB: An evaluation of footwear worn at the
time of fall-related hip fracture. Age Ageing 2003, 32(3):310-314.
16. Nagata H, Watanabe H, Inoue Y, Kim I: Frictional values meas-
ured by various methods and their validities as an index of
fall risks. 3rd Australian and New Zealand Falls Prevention (ANZFP) Con-
ference: 2008; Melbourne, Australia 2008:50.
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