ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

VALIDATION AND CALIBRATION PROCESSES OF A
MUSCULOSKELETAL MODEL OF THE HAND AND FOREARM
1. ABSTRACT
N. Vignais 1 and F. Marin 2
Musculoskeletal disorders linked to professional manual tasks can now be considered as
a public health issue because of their associated costs. In order to prevent these workrelated
disorders, knowledge of internal biomechanical parameters of the hand and
forearm such as muscle forces and joint loads is essential. To this aim, a biomechanical
model of the hand and forearm representing the whole complexity of this
musculoskeletal system (21 segments, 21 joints and 46 musculotendon units) has been
developed. In order to confirm results obtained by the musculoskeletal model of the
hand and forearm, a validation process is performed based on EMG signals and external
forces (from a manual dynamometer). Two validation parameters have been defined to
compare real measures and estimations from the model: muscle activation and the
resulting external force. These parameters are compared for different industrial manual
tasks (grasping, pinching, holding...). Although amplitude differences are observed, first
results show qualitative correspondences between experimental and simulation data. In
order to refine the musculoskeletal model of the hand and forearm, a calibration process
based on the coupled measure of EMG and manual dynamometer is proposed. Both
processes are discussed and results provided by the musculoskeletal model are detailed.
This work is a preliminary step to improve the robustness of musculoskeletal modelling
for biomechanical and ergonomic analyses.
2. INTRODUCTION
Manual tasks can be considered as any task involving lifting, pushing, pulling, carrying,
moving manipulating, holding, or restraining a person, animal, or item. When
performed in a hazardous way, these manual activities lead to musculoskeletal disorders
(MSDs) (Burgess-Limerick 2007). For example, the prevalence of musculoskeletal pain
in the wrist/hand anatomical area was equal to 23.2% in the Dutch population aged 25
years and over (Picaven and Schouten 2003). In Australia, manual tasks at work
represented 42% of all claims in six years to June 2003 and had associated costs of $12
billion (Burgess-Limerick 2007). In France in 2007, 44.5% of occupational diseases
consisted of MSDs located in elbow, wrist, hand and digits (Euzenat, 2010).
In order to detect hazardous manual tasks and prevent from MSDs appearance,
knowledge of the internal biomechanical parameters of the musculoskeletal system of
the hand and forearm is fundamental. As such in vivo measurements are difficult to
obtain (Rasmussen et Dendorfer, 2009), some computer simulations and mathematical
1 Postdoctoral Research Assistant, BioMechanics and BioEngineering (UMR7338), University of
Technology of Compiègne, Research Centre, rue du dct Schweitzer, 60200 Compiègne, France
2 Professor of Biomedical Engineering, BioMechanics and BioEngineering (UMR7338), University of
Technology of Compiègne, Research Centre, rue du dct Schweitzer, 60200 Compiègne, France