Idiopathic clubfoot causes severe deformity of the foot and lower leg. Due to the complex anatomy and small size of the foot, the condition is difficult to define and describe. This study focused on 3D modeling of different foot positions associated with clubfoot relapse, and investigation of muscle parameters. The 3D modeling was performed in the AnyBody Modeling System to retrieve information about muscle length. Musculoskeletal modeling could provide further understanding of the condition and contribute to assessment and treatment evaluation. Five children that received clubfoot treatment as infants, and five typically developing children, serving as a control group, participated in the study. Despite treatment with the Ponseti method, Achilles tenotomy and use of an abduction orthosis, all participants of the clubfoot group showed signs of relapse. In total, seven affected legs were studied. Data from gait analyses of all participants were compiled and interpreted in the AnyBody Modeling System. The Plug-in-Gait Model for lower extremities and the Oxford Foot Model were used as marker protocol for the study. Studied lower leg muscles were Gastrocnemius Lateralis, Gastrocnemius Medialis, Soleus Lateralis and Soleus Medialis. Muscle length, defined as length of contractile element, for each leg and participant were evaluated using the AnyBody model template LowerExtremity. Compared to the control group, the models of the clubfoot group presented shorter mean muscle lengths of all investigated muscles. / Idiopatisk klumpfot orsakar allvarlig deformation av fot och underben. På grund av fotens anatomi och ringa storlek kan tillståndet vara svårt att beskriva och definiera. Denna studie innefattade 3Dmodellering av olika fotpositioner orakade av recidivklumpfot, för att undersöka muskelegenskaper. AnyBody Modeling System användes för att generera 3D-modeller och ta fram information om muskellängd. Muskuloskeletal modellering skulle kunna öka förståelsen för sjukdomen och bidra till förbättringar av initial bedömning och utvärdering av behandling. Fem barn som behandlades för klumpfot efter födseln deltog i studien. Även fem typiskt utvecklade barn medverkade och fungerade som en kontrollgrupp. Trots behandling med Ponseti-metoden, hälseneförlängning och användning av abduktionsortos, uppvisade samtliga barn i klumpfotsgruppen tecken på återfall. Totalt studerades sju ben med recidivklumpfot. Data från gånganalyser av deltagarna sammanställdes och analyserades i AnyBody Modeling System. Plug-in-Gait Model för nedre extremiteter och Oxford Foot Model användes som markörprotokoll. Under studien analyserades underbensmusklerna Gastrocnemius Lateralis, Gastrocnemius Medialis, Soleus Lateralis och Soleus Medialis. Muskellängd (längd av kontraktilelement) för varje patient och ben beräknades med hjälp av modellmallen LowerExtremity i AnyBody Modeling System. Jämfört med kontrollgruppen visade klumpfotsgruppen kortare medelmuskellängder för samtliga av de analyserade musklerna.

Bone loss and muscle atrophy are two main physiological conditions affecting astronauts while being in space. In order to counteract the effects, at least two hours of aerobic and resistant countermeasure exercise is scheduled into their working day, seven days a week. Yoyo Technology AB has developed a resistance exercise device based on the flywheel principle, providing a load independent of gravity. However, there is no biomechanical research done on the efficiency of the device in microgravity, from a human movement point of view using simulation software. The aim of this thesis was to evaluate the effects of performing a leg press on the flywheel exercise device in a microgravity environment. Simulations of performing a flywheel leg press in earth gravity, microgravity and performing a conventional squat were done. The evaluated parameters were reaction forces, joint angles, joint moments, joint powers and muscle recruitment in the lower extremities. The simulations were done using a biomechanical simulation software based on a motion capture data collection. From the results two conclusions were proposed. Performing a flywheel leg press in microgravity environment or on earth provides at least as much peak moment as a body weighted squat performed on earth. Furthermore, performing a flywheel leg press in microgravity will induce a higher activity level among hip extensors and knee flexors compared to performing a flywheel leg press on earth.

This thesis work comprises the working and simulation procedures being involved in simulating motion capture data in AnyBody Modeling System. The motion capture data used in this thesis are ballet movements from dancers of Östgöta ballet and dance academy. The ballet movements taken into consideration are the arabesque on demi-pointe and pirouette. The arabesque on demi-pointe was performed by two dancers but the pirouette is performed by only one dancer. The method involved recording ballet movements by placing markers on the dancer's body and using this motion capture data as input to AnyBody Modeling System to create a musculoskeletal simulation. The musculoskeletal modeling involved creating a very own Qualisys marker protocol for the markers placed on the ballet dancers. Then implementing the marker protocol onto a human model in AnyBody Modeling System by making use of the AnyBody Managed Modeling Repository (TM) and obtain the kinematics from the motion capture. To best fit the human model to the dancer's anthropometry, scaling of the human model is done, environmental conditions such as the force plates are provided. An optimization algorithm is conducted for the marker positions to best fit the dancer's anthropometry by running parameter identification. From the kinematics of the motion capture data, we simulate the inverse dynamics in AnyBody Modeling System. The simulations explain a lot of parameters that describe the ballet dancers. Results such as the center of mass, the center of pressure, muscle activation, topple angle are presented and discussed. Moreover, we compare the models of the dancers and draw conclusions about body balance, effort level, and muscles activated during the ballet movements.