- In your favorite file browser, navigate to your OpenSim Resources directory (e.g. [Your Documents Directory]/OpenSim/OpenSim 4.01), then find the folder Models/ToyDropLanding.
- Copy the ToyDropLanding folder to a location of your choice. This well let you play with the models without fear of corrupting the example for future reference. From now on, we will refer to this location as [Example_Dir]/ToyDropLanding
- In the OpenSim GUI, select File>Open Model....
- In the dialog box that appears, navigate to [Example_Dir]/ToyDropLanding and select ToyLandingModel.osim.
- Open a new plot window by selecting Tools>Plot....
- Click the Y-Quantity... button and select Unassisted(DegLoad file.)... near the bottom of the list to select kinematic data from your last simulation. If you saved the motion to a file, you can also use the Load file... option and navigate to the desired results file.and navigate to the file you saved in Part A.
WARNING: You must load you results as indicated in Step 2 to plot kinematic data in degrees. Loading the results by selected Unassisted(Deg.)... in the Y-Quantity... drop down menu will load the results in radians. This is a bug that will be addressed in a future OpenSim release.
- In the Filter by pattern text box, type "sub" to filter the results to just those containing the text string "sub".
- Select subtalar_angle_r/subtalar_angle_r/value and click OK.
- Select X-Quantity>time to choose time as the independent variable.
- Click Add to display the data as a curve.
- Click on "Figure 1" in the Curves List to highlight it. Click again to rename. Modify the title field (e.g., "Ankle inversion (subtalar angle) during drop landing"). Alternatively, right click and edit using in the Properties menu.
- Click on "subtalar_r/subtalar_angle_r/value" to highlight the curve label in the Curves List box and click again to rename. Since this simulation used a model with no assistive devices, change this curve name to "Unassisted".
- Answer the questions below, then minimize the plot window. Keep the plot window open so you can use it to compare these results to simulations with an AFO.
- What is the maximum subtalar angle during the drop landing?
- Would an ankle inversion injury have occurred during this landing? According to previous research (Siegler et al., 1990; Lapointe et al., 1997), angles larger than 25 degrees (0.436 radians) may cause injury.
III. Analyze the effects of an ankle–foot orthosis (AFO) on ankle inversion
Matt DeMers, Ajay Seth, Jen Hicks, Jeff Reinbolt, Ajay Seth, Scott Delp with input and testing help from many others