Visualize EMG reference data

If your Vicon Nexus trials contain EMG data, you can visualize this in Nexus Insight reports.

You can display EMG reference data in Nexus Insight as follows:

• Envelope reference data, as mean ± std (mean ± standard deviation), as shown by the wide gray line superimposed on the relevant area of a graph in the following image. 

• Activation bars, as shown by the gray rectangle along the bottom of the graph in the following image.

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To find out more, see the following topics:

For information on deleting EMG reference data from a report, see Remove EMG reference data.

Add EMG envelope reference data to a report

To add EMG envelope reference data to a report, you generate the C3D file that contains the EMG data in Nexus, identify the correct names for the EMG channels in Nexus Insight, add these channel names to a spreadsheet containing your EMG reference data and then use the C3D file and a template you create in Nexus Insight to create a report.

For details of this procedure, see the following steps.

To add EMG reference data to a report:

1. Make sure that the C3D file generated in Nexus contains the required output names, for example, RQuad.EMG1-value, as well as any other information required, such as gait events (see Prepare your data in Nexus).

2. To identify the correct names for the EMG channels, in Nexus Insight, create a report using the C3D file that you prepared in the previous step and the No template (single trial only) template.

3. Find the names for the EMG channels in either of the following ways:

   • View the titles of the graphs in the EMG section.

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   • Click Edit to open the Edit report dialog and under Graph selection, expand the EMG section to display a list of the titles.
     Tip: This method enables you to copy and paste (Ctrl+C and Ctrl+V) the names, which ensures they remain exact copies.

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4. Create (or open) a correctly formatted Excel spreadsheet for your reference data (see Excel format for reference data).

5. Add the EMG data to the reference data file. To do this, for each required EMG channel, name and structure an additional tab in the same way as for a Kinematics / Kinetics tab (so the column headings are %, mean and std), but name the additional tab EMG<channel name>, where <channel name> is the name you noted in Step 3. This example shows a tab named EMG RQuad.EMG1-value.

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   Important: EMG values in reference data files must be in V and the names of the tabs must be exact copies of the names displayed in Step 3 above.

6. Save the reference data file, giving it a new name, in the References subfolder in C:\Users\Public\Documents\Vicon\NexusInsight (for details, see Import and visualize reference data).
   Important: To ensure changes in an Excel reference file are applied, when you make changes to an Excel reference file, always save it with a new file name before adding it to a report.

7. In Nexus Insight, click Export and export the report as a template (JSON file) to the usual Nexus Insight templates folder at
   C:\Users\Public\Documents\Vicon\NexusInsight\Templates

8. Close and restart Nexus Insight.

9. Create a new report using the same C3D file, the report template you exported in Step 7 and the reference data file you saved in Step 6.

10. In the report, expand the EMG section to display the EMG reference data.

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To add EMG reference bars, see Add EMG reference bars to a graph.

Add EMG reference bars to a graph

To display EMG reference bars for a graph:

1. Ensure you have added EMG reference data to your report as described in Add EMG envelope reference data to a report.

2. In your EMG reference data file, on each Excel sheet that corresponds to a graph containing EMG data, add a column with the heading activation.

3. In the activation column, insert either 0 or 1, depending on where you want to display the EMG bars.
   In the following example, EMG reference bars will be displayed for 0–25% of the gait cycle.

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4. Save your EMG reference data file under a new name.

5. Create a new report using the same C3D file and report template but this time, select the new reference data file.
   The reference bars, as well as the EMG envelope reference data, are displayed in the report.

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