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A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye
A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye
Theses
Several studies such as the equilibrium point hypothesis (EPH) purport that the motor signals that descend from the brain instead of encoding muscle torques, influence an existing relationship between muscle torque and body configuration.
In the present study, the possibility of torque depending explicitly on position was tested using a task in which subjects (N=5) moved a simulated weightless frictionless mass through a small (<8 degree) elbow extension in order to move a cursor on a screen to a target location. Each subject completed 720 trials. On ~10% of trials the simulated mass was increased unknown to the subject. The relationship between the cursor’s position and the torque applied to the system was held constant even when the simulated mass was increased. Thus, any change in torque produced was neither due the subjects’ perception of the mass nor due to their perception of the cursor. The time at which the subjects torque changed direction was seen to be significantly different (p<0.005) during trials which the mass changed. This change in torque is concluded to be position-dependent. However the possibility of this being a merely mechanical effect could not be ruled out by due to poor EMG collection.
A post-hoc analysis of different position-dependent motor control models, was done. Particularly, an exponential spring model, a linear spring model, and a linear spring with relative damping model were each tested to see how well …
Posterior Stabilized Knee Design Biomechanical Considerations, Donald E. Mcnulty
Posterior Stabilized Knee Design Biomechanical Considerations, Donald E. Mcnulty
Theses
Numerous posterior stabilized knee systems are available for primary and revision total knee arthroplasty. Design of these systems requires an understanding of the articulating geometries and kinematic/kinetic biomechanical considerations of the normal knee. The findings for the normal knee are integrated into the design of a prosthetic system.
The natural femoral, tibial and patella articulating geometries are defined to enable subsequent kinematic and kinetic analyses. The articulating geometries are characterized from review of anthropometric studies of the tibiofemoral and patellofemoral joint.
The kinematic analysis of the natural knee defines knee motion in terms of rotation, adduction/abduction, range of motion and …