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FAIL MODE AND EFFECTS ANALVSIS (FMEA) APPLIED TO BIOFOOT/IBV2001 ®
EQUIPMENT ADAPTATION FOR LONG JUMP
Enrique Alcantara, Javier Gamez, Pedro Perez, Antonio Martinez,
Lirios Dueiias.
Institut of Biomechanics of Valencia (IBV)
Valencia. Spain
Increasingly, techniques and instruments coming from different fields of science are being
used in sports research. This study proposes the application of an engineering
methodology, the FMEA, for the adaptation of a plantar pressure measurement device to
its safe and reliable use in the long jump analysis. This project's aim is to analyse the
possible failures of the measurement equipment when used for long jump study, propose
and validate changes in the measure equipment and in the research protocol. The FMEA
methodology allowed to identify and to give priority to ninety four possible failures and
their effects. Sixty four of them were solved, the remaining were of very low importance.
In any case, further improvements were envised to eliminate all those possible failures. A
new plantar pressure measuring equipment and a modified study protocol were obtained
as a result.
KEY WORDS: track and field, FMEA, biomechanics, long jump, plantar pressures.
INTRODUCTION: A great number of instrumental techniques are used in Sports
biomechanics research. One of the more recently incorporated is the instrumented insoles
equipment for plantar pressures registering. This technique was developed in order to study
human gait (Hoyos, J.V. et al. 1984) and since then its use has been Widely extended to
orthopaedics and others. Its applications in sports have mainly focussed in running
(Ferrandis, R. 1989) and soccer (Brizuela, G. et al. 1998) with little reported use in other
sports disciplines. We found several problems to use this technique for registering plantar
pressures during long jump takeoff. Only a work was found in literature ( Perttunen and cols
2000). Commercially available systems (BIOFOOT/IBV 2001®, EMEDPEDAR and
TEKSCAN) show a similar configuration and were considered as potentially dangerous for
the athlete, as well as to disturb and even modify the gesture. Thus, adaptation of
instrumented insoles to long jump was deemed necessary as the previous step to
biomechanical analysis of the takeoff. Therefore, the objective of this study was to adapt an
existing and already available plantar pressures measurement equipment (BIOFOOT/IBV
2001 ®), to the study of long jump when increasing the athlete's safety and reducing the
modification of the gesture. A clearly established procedure called Failure Mode and Effects
Analysis (FMEA) was used. This method has been widely used in many fields of engineering
to improve processes, equipment and machinery (Passey, R. 1999, Willis, G. 1992).
METHODS: The equipment to be adapted consisted of a commercial system, BIOFOOT/IBV
2001 ® (Figure 1). It consists of 64 piezoelectrical ceramics sensors 0.7 mm thick,
distributed into a flexible insole. The insole is placed into the shoe of then athlete and the
plugged into an amplifier fixed at the athlete's tibia by an elastic band. The amplifier is
connected to a telemetry equipment to transmit the data to a portable PC, so that the user
can move freely around the test area. The work carried out consisted of first applying the
FMEA method to identify and rate possible equipment failures; second, developing a new
equipment to avoid those failures, and finally, validating the new equipment. FMEA is an
engineering qualitative methodology that follows an established procedure to compute a
coefficient called Risk Priority Number (RPN) that is used to arrange in order of increasing
importance the possible failures allowing to identify the need and urgency of modifications.
The procedure consists of the following steps: 1. Identification of equipment elements. 2.
Identify potential failures of each element and their effects on the athlete and the
experimental procedure. This was done by experts' analysis of filming from different long
jumps with two athletes wearing the instrumented insoles equipment. 3. Establish possible
causes for the failures and their effects by experts. 4. Compute the Risk Priority Number as.
RPN = severity x occurrence x detection probability, which are given a number between 1
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and 10 as a function of estimating the severity of failures' effect, the frequency with which it
could occur and the possibility of detecting the failure, The greater the RPN the more
important the failure. Experts in biomechanics, sports and instrumentation proposed the
different solutions for most important failures (higher RPN) and quoted their feasibility. The
solutions were implemented in the development of a new equipment and tested on a
prototype. Validation was done by experts' observation on long jump filming from 2 athletes
wearing the new equipment. They evaluated that risks had been eliminated and that no new
ones appeared.
RESULTS AND DISCUSSION: Sensors, amplifier, cable, transmitter, insole and others were
the elements (figure 1) of the equipment considered for the FMEA study. This analysis
allowed to identify ninetyfour possible failures that could affect both the athlete and the
investigation during the long jump. Most relevant failures were those that could result in
athlete's injury, as for example amplifier or transmitter damage during landing by impacting
the athlete or skin abrasion in the flight phase due to cable interference that could also
modify the gesture performance. Also, potential failures were identified as being able to
affect the experimental procedure as far as sensors could fail the sand or break by very high
pressures at take off that would distort the measures or cause information loss. In this sense,
design modifications were proposed for higher RPN failures. As a result, a new equipment
was developed (Figure 1) as well as an improved experimental procedure. The most relevant
failures, their RPN, proposed modifications and feasibility are showed in table 1 as an
example.
Table 1. Example of the FMEA procedure showing the elements, potential failure their effects and
causes as well as the RPN, solutions proposed and their feasibility.
RPN Solutions
Potential effects
Potential causes
Amplifier
Potential
failure
damage
Hurt athlete
Knock
270
Transmitter
damage
Hurt athlete
Knock
270
Finishing
Crease
210
180
180
180
180
162
Element
Cable
insoles
Burn
High abrasion
damage
Equipment damaged
Amplifier
Wrong location
Hurt athlete
Cable
Fixation
harness
Fixation
harness
Cable
Rough
Get loose
Hurt athlete
Hurt athlete
Inadequacy to
gesture
Finishing
Velcro no ok
Tension no ok
Hurt athlete
Material no ok
Tear
Athlete fall
Inadequate length 162
Cable
Tear
Hurt athlete
Inadequate length 162
Sensors
Damage
Equipment damaged
Overloading
150
Shock
absorber
Shock
absorber
Protection
Inspection
and
correct
desinq
Polyvalen
ce
Protection
velcro®
OK
Elastic
Elastic
cable
Elastic
cable
Set up
Feasibility
easy
easy
easy
easy
difficult
easy
easy
easy
easy
easy
easy
The changes that were proposed focussed on the relocation of some elements of the
equipment and the adaptation of the instrumented insole to such changes. The transmitter
was placed on the chest, supported by a fixation harness, placed on the thorax and fixed on
the back. The amplifier was moved to the medium section of the tibia, in the plane zone
(internal part of the leg). The cable, which connects the amplifier with the transmitter, was a
spiral cable with a smooth finishing. Design modifications were applied to the insole in its
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connection band, due to the new location of the amplifier. These consisted of a new design
of the connection band with a sinuous form (Figure 2). Concerning the experimental protocol,
checking points were included to assess sensors function and to verify that all the elements
of the equipment were functioning correctly and that neither sand nor the strong impact
caused breakdowns, which would distort the measures.
Figure 2. New design of connection band with a sinuous form (blue) and the insole form (violet).
The validation work showed that most of the identified risks of failure have been eliminated
with the new equipment and FMEA showed only low RPN risks. Only NN out of 94 possible
failures remained with the new equipment. In this sense, further improvements of the
equipment were proposed.
Table 2. Possible further improvements for the BIOFOOT/IBV 2001 ®.
Element
Insoles
Amplifier
Transmitter
Cable
Fixation
harness
i
Improvement
Modify the curve of the connecting band
Divide the connectinq band in two
Avoid that the fixation band velcrum gets in touch with subject's skin
Protect the amplifier against sand entering
Fixation band with breathable material
Place a cushioninq material between the emitter and the subjects chest
Fix the cable to the athlete by an elastic band
Dispose an spiral at knee level for the cable
Improve harness comfort
Use velcro® back fixation
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Figure 1, Difference between the initial BIOFOOT/IBV 2001®. Equipment (left) and the long jump
adapted prototype of BIOFOOT/IBV 2001® equipment (right).
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309
After the last phase of the process, the main modifications proposed were: the location of the
transmitter, which for design reasons of the equipment would be better placed horizontal; the
protection of the amplifier through neoprene and elastic fabrics; and the design of the
connection band of the insole, caused by its modified curvature in order to fit better the
amplifier. This article introduces the fail mode and effects analysis (FMEA) method as an
ordered, and established qualitative procedure for adapting existing biomechanical
instrumentation to be used in sports where current devices could either damage the athlete
or negatively influence the technical performance of the gesture. It has been successfully
used to adapt a plantar pressure registering device for the study of long jump takeoff,
assuring the physical integrity of the athlete and the quality of the sports study. In the future,
more improvements focussed on electronics could be studied, which would improve the
performance of the equipment as they would reduce the size of both, the amplifier and the
transmitter.
CONCLUSIONS: The use of FMEA has allowed the development of an equipment for plantar
pressure analysis during long jump takeoff reducing athlete damage risk and improving the
reliability of experimental protocol.
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Vieten, 120123, Konstanz, Germany.
Ferrandis, R; Ramiro, R; Sanchez, J.; Alepuz, R; Latorre, P (1989). Patologla del corredor.
Cap 2. En: El calzado para carrera urbana: criterios biomecanicos de diseno. Instituto de
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Hoyos, J.v.; Vera, P.; Nieto, J.; Garcia, M. ; Ramiro, J.; Ayora, M.; Rodrigo, J.L.; GomezFerrer, R (1984) Biomecanica de la marcha humana (11): el laboratorio de marcha del
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Pertunen, J.; kyrolainen, H.; Komi, P. (2000) Biomechanical loading in the triple jump. J.
Sport Science, 18, 363370.
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