Step 7 - Calculate powers

The final step in the kinetics process is to calculate joint powers. Joint power is calculated using the proximal and distal segments, the joint angular velocity, and joint moment. Both the joint angular velocity and joint moment can be extracted or automatically calculated from the joint reactions we defined in an earlier step.

To calculate joint powers:

1. Create a new variable called NormalizedLeftAnklePower.
2. For the function type, select Kinetics and for the function, select Calculates power from reaction A, parent segment B, child segment C, D normalizes.
3. For the Input Variable Types (A-D), make sure the following are specified in order: Reaction, Segment, Segment, Number.

4. For the Input Variables, select LeftAnkleReaction, LTI, LFO, and Bodymass for A, B, C, and D, respectively.

   

5. Copy and mirror.

Note the following points about this calculation:

• This calculates powers with respect to the distal segment of the joint.
• To calculate a three-component power output, from the list of available Kinetics functions, select Calculate XYZ power from reaction A, parent segment B, child segment C, D normalizes.