Experiment vs. Modelling and Simulation – a Task for Biomechanists
Vladimir Medved
Professor
University of Zagreb, Faculty of Kinesiology
Zagreb, Croatia
E-mail: vmedved@ffk.hr
Abstract: The approach in the study of locomotion biomechanics
combines experimental work with modelling and simulation.
Reflection is given on the line of development of kinesiological
biomechanics at the University of Zagreb, characterized
primarily by experimental research, but with occasional
theoretical contributions as well. Empirically-based criteria of
locomotor skills were determined. A concept of virtual-reality
assisted movement diagnostics was devised. Current status of
laboratory equipment allows advanced research to be pursued.
In particular, multi-body dynamics approach might be realized,
with good possibilities for experimental testing. Potential
applications are envisaged both in the realms of sports
locomotion and of medical pathologies.
1.
INTRODUCTION
We witness the establishment of modern biomechanics
during the last few decades, with only nowadays it starting to
become broadly applied. There is a plethora of research
contributions, documented in professional journals,
characterized basically with a measurement-type approach.
Very often measurement data are interpreted almost directly,
without serving to test some explicit theoretical hypothesis.
However, the only comprehensive approach for solving
biomechanical problems is the one combining measurement
with modelling (which incorporates inverse dynamics) and
simulation, which – if necessary – are to be applied
iteratively. This paper reflects on the situation at the Faculty
of Kinesiology (the former Faculty of Physical Education),
University of Zagreb. Two decades of experience in
experimental research, primarily of electromyographic
(EMG) and kinetic signals, have enabled turning at this point
into a more theoretical approach.
2. BIOMECHANICS METHODOLOGY
In natural sciences, modelling approach is combined with
experimental observation as a means to acquire new
knowledge about a phenomenon. During the last century,
besides classical mechanics, systems theory and cybernetics
have provided the methodological basis for the research of
neuro-musculo-skeletal (N-M-S) system. This is evidenced,
for instance, in model approaches by McMahon [1] and
Vodovnik [2]. In these approaches, neuro-muscular structures
have been modelled successfully via the mathematical
apparatus of systems theory and systems analysis, so that
useful simulations of their function were possible. This
resulted with successful practical realizations such as, for
instance, fast running tracks, hip fall prevention systems,
functional electrical stimulation (FES) devices to aid
pareplegics, to name but a few. Modern research applies even
new tools of modelling and simulation of N-M-S system such
as neural networks and the like, integrating biomechanics
with neurophysiology and motorics [3].
3. DEVELOPMENT OF KINESIOLOGICAL
BIOMECHANICS IN ZAGREB
Two decades of kinesiological biomechanics at the
University of Zagreb have been devoted mainly to
researching sportive movements such as in sports gymnastics,
rowing, skiing, etc. Gradual development and implementation
of biomechanical measurement techniques have taken place
during this period [4,5]. Quantitative biomechanical measures
of locomotor skills were developed. Research projects were
conducted, focused to neuro-muscular system function
diagnostics, both for sportive and pathological locomotion. A
recent project is oriented towards creating a centre for
locomotion studies where not only movement diagnostics but
also locomotion expert systems would be developed.
Research and teaching efforts have resulted, today, in a
modern laboratory at a disposal, enabling measurements with
high accuracy of various locomotor patterns, as well as new
teaching vistas [6].
On the other side, at the conceptual level, improved
bioelectric signal analysis and processing, as well as
diagnostics of whole body movement have been proposed
including such software vehicles as pattern synthesis and
virtual reality [7,8]. These approaches rely on combining
model-based generated quantities with experimental data in
order to realize improved diagnostics of studied movement
stereotypes. A future research scenario might include
approaches of this kind to be realized in practice. Simulation
is becoming ever more an important vehicle in engineering,
with biomedical engineering being no exception. A good
example - a success story of sorts - comes from the Delp
model aimed primarily for clinical ortopaedics [9]. We are
also oriented towards multi-body anthropomorphic models,
whose dynamics we aim to study in co-operation with the
Faculty of Mechanical Engineering and Naval Architecture
[10]. Apart from this, among our current tasks is also the
study of the knee joint (a joint especially prone to injuries),
by modelling and testing its proprioceptive features in
particular.
4. CONCLUSION
Backed up by two decades of experience in empirical
approach to studying human movement, our research is now
at the turning point when a more theoretical emphasis is
seeked. The trend has been noted which began with
accumulation of experimental data, their analysis and
presentation, and now developing into a comprehensive,
model-based approach for studying human movement.
ACKNOWLEDGMENT
The help of the Ministry of Science, Education and Sport
of the Republic Croatia is gratefully acknowledged (project
number 0034-206: “Creating Centre of Excellence for
Locomotion Study“)
REFERENCES
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