Visual 3 D Inverse Dynamics and Joint Power

Visual 3 D Inverse Dynamics and Joint Power Analysis

Marker and Force Data • marker data come in a. C 3 D file created by Vicon, Motion Analysis, Qualysis or similar motion capture system • SIMI and APAS may also be used but data must be placed in a ASCII (. FSV) file by, for example, Bio. Proc 2/3 • force data come with the. C 3 D file but may also be collected and placed in an ASCII (. FSV) file by Bio. Proc 2/3 • data may be streamed directly to Visual 3 D using newest version of Visual 3 D and compatible motion capture system, e. g. , Nexus Biomechanics Laboratory, School of Human Kinetics

Creating the Model • first a static trial is loaded to create the model (you can use a movement trial) • a previous model may be used for a similar marker set • model is customized for each participant (mass and height etc. ) • ideally markers are located at each joint but these markers do not have to be included in the movement (dynamic) trials • should save the model file (. MDH) separately for use with other trials or experimental conditions of the same person • new models must be created for each new marker set • modeling is done using graphical user interface (GUI) Biomechanics Laboratory, School of Human Kinetics

Model Building Screen • create segments • create landmarks • enter body mass and height Biomechanics Laboratory, School of Human Kinetics

Movement Trials • one or more movement trials may be loaded into same workspace (. CMO), essential if trials are to be averaged • model is applied to each trial • trial may be viewed with bones or geometrical solids for each segment • ground reaction forces should be checked • errors in force platform locations and parameters may be checked and changed in necessary Biomechanics Laboratory, School of Human Kinetics

Workspace Screen • static trials • movement trials • tags to identify experimental conditions Biomechanics Laboratory, School of Human Kinetics

Event Labeling • if events were not created by motion capture software they can be added automatically (via a pipeline) or manually with Visual 3 D • special events used for reports can also be added – e. g. , Begin, End, Impact • events may be checked for accuracy using GUI Biomechanics Laboratory, School of Human Kinetics

Signal and Event Processing Screen • signals and events tab • edit events • signal tree • body at current event • signal histories with events marked Biomechanics Laboratory, School of Human Kinetics

Data Processing Pipeline • a pipeline may be applied to process the data for inverse dynamics, energy or moment power analyses • a script may be used to perform these operations • a typical script (. V 3 S) includes interpolation and data filtering • special forces may be added such as moving force platforms or pedal forces Biomechanics Laboratory, School of Human Kinetics

Pipeline Form • commands • pipeline • options • import signals Biomechanics Laboratory, School of Human Kinetics • load/save scripts

Graphical Reports • reports including graphs of the various kinematics and kinetics are created last • special filters may be used to display only certain types of trials, e. g. , right vs. left leg starts, barefoot vs. shod gait, loaded vs. unloaded lifts • these categories are created in the workspace area • basic reports (. RGT) may be loaded or created and saved for later repeated use graphs may be exported for presentation Biomechanics Laboratory, School of Human Kinetics

Reporting Screen • contents of pages • report pages • graphical or tabular reports Biomechanics Laboratory, School of Human Kinetics

Export Data to Mat. Lab or Bio. Proc 3 • kinematic or kinetic data may be exported in. C 3 D or ASCII files • Bio. Proc 3 has capability of computing total, internal and external work, angular impulses and work done by individual bursts of power • script is used to create ASCII file for Bio. Proc 3 • Mat. Lab can compute foot clearance Biomechanics Laboratory, School of Human Kinetics

Bio. Proc 3: External/Internal/Total Work • external work • internal work • total work Biomechanics Laboratory, School of Human Kinetics

Bio. Proc 3: Work Done in Bursts • work done • which moment of force • peak power • peak moment • mean power • total work done Biomechanics Laboratory, School of Human Kinetics