simtk.org

Hi,

I've been looking into the moment arms that are created by the adductor magnus muscles about the hip joint. The first thing I've done is to plot the adductor magnus muscle using 'hip_adduction_r moment arm' for the Y quantity and 'hip_adduction_r' for the X quantity. I understand what is being displayed and how it is calculated using the equation ma = dl/dtheta.

My question is is there any way to see the moment arm about different axes? The above example is for the moment arm that produces a moment along the x axis (theta being adduction, which is rotation about the x axis), but this does not give me any information about the moment that will be created along the y and z axis when the adductor muscles contract during adduction.

I've looked into using 'hip_flexion_r moment arm' as a Y quantity and 'hip_adduction_r' as a X quantity on the plotting tool, however I am unsure how to interpret the resulting graph. Does a plot like that mean anything if the X and Y quantities are for different motions? I was hoping that by selecting flexion as a Y quantity that it would generate information about how the muscle creates a z axis moment arm during adduction.

Thanks for any help,

Connor