Flexible multibody approach in bone strain estimation during physical activity:
Kłodowski, Adam (2012-10-26)
Väitöskirja
Kłodowski, Adam
26.10.2012
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-265-289-8
https://urn.fi/URN:ISBN:978-952-265-289-8
Tiivistelmä
Bone strain plays a major role as the activation signal for the bone (re)modeling
process, which is vital for keeping bones healthy. Maintaining high bone
mineral density reduces the chances of fracture in the event of an accident.
Numerous studies have shown that bones can be strengthened with physical
exercise. Several hypotheses have asserted that a stronger osteogenic (bone
producing) effect results from dynamic exercise than from static exercise. These
previous studies are based on short-term empirical research, which provide the
motivation for justifying the experimental results with a solid mathematical
background. The computer simulation techniques utilized in this work allow for
non-invasive bone strain estimation during physical activity at any bone site
within the human skeleton. All models presented in the study are threedimensional
and actuated by muscle models to replicate the real conditions
accurately.
The objective of this work is to determine and present loading-induced bone
strain values resulting from physical activity. It includes a comparison of strain
resulting from four different gym exercises (knee flexion, knee extension, leg
press, and squat) and walking, with the results reported for walking and jogging
obtained from in-vivo measurements described in the literature. The objective is
realized primarily by carrying out flexible multibody dynamics computer
simulations. The dissertation combines the knowledge of finite element analysis
and multibody simulations with experimental data and information available from medical field literature. Measured subject-specific motion data was
coupled with forward dynamics simulation to provide natural skeletal
movement. Bone geometries were defined using a reverse engineering approach
based on medical imaging techniques. Both computed tomography and
magnetic resonance imaging were utilized to explore modeling differences.
The predicted tibia bone strains during walking show good agreement with invivo
studies found in the literature. Strain measurements were not available for
gym exercises; therefore, the strain results could not be validated. However, the
values seem reasonable when compared to available walking and running invivo
strain measurements. The results can be used for exercise equipment
design aimed at strengthening the bones as well as the muscles during workout.
Clinical applications in post fracture recovery exercising programs could also
be the target. In addition, the methodology introduced in this study, can be
applied to investigate the effect of weightlessness on astronauts, who often
suffer bone loss after long time spent in the outer space.
process, which is vital for keeping bones healthy. Maintaining high bone
mineral density reduces the chances of fracture in the event of an accident.
Numerous studies have shown that bones can be strengthened with physical
exercise. Several hypotheses have asserted that a stronger osteogenic (bone
producing) effect results from dynamic exercise than from static exercise. These
previous studies are based on short-term empirical research, which provide the
motivation for justifying the experimental results with a solid mathematical
background. The computer simulation techniques utilized in this work allow for
non-invasive bone strain estimation during physical activity at any bone site
within the human skeleton. All models presented in the study are threedimensional
and actuated by muscle models to replicate the real conditions
accurately.
The objective of this work is to determine and present loading-induced bone
strain values resulting from physical activity. It includes a comparison of strain
resulting from four different gym exercises (knee flexion, knee extension, leg
press, and squat) and walking, with the results reported for walking and jogging
obtained from in-vivo measurements described in the literature. The objective is
realized primarily by carrying out flexible multibody dynamics computer
simulations. The dissertation combines the knowledge of finite element analysis
and multibody simulations with experimental data and information available from medical field literature. Measured subject-specific motion data was
coupled with forward dynamics simulation to provide natural skeletal
movement. Bone geometries were defined using a reverse engineering approach
based on medical imaging techniques. Both computed tomography and
magnetic resonance imaging were utilized to explore modeling differences.
The predicted tibia bone strains during walking show good agreement with invivo
studies found in the literature. Strain measurements were not available for
gym exercises; therefore, the strain results could not be validated. However, the
values seem reasonable when compared to available walking and running invivo
strain measurements. The results can be used for exercise equipment
design aimed at strengthening the bones as well as the muscles during workout.
Clinical applications in post fracture recovery exercising programs could also
be the target. In addition, the methodology introduced in this study, can be
applied to investigate the effect of weightlessness on astronauts, who often
suffer bone loss after long time spent in the outer space.
Kokoelmat
- Väitöskirjat [1037]