Movie 4.

MoCap video for the 90^° with a side-step condition. The video shows the model (represented by skeletal and muscular elements), four force plates (grey), the ground reaction force vector (blue line through model), force plate readings (blue lines below the force plate), experimental marker locations (blue spheres), virtual markers (red spheres with coordinate system arrows) and global coordinate system (yellow arrows). Participant's arms swung naturally while walking and were not crossed over their chest during the trial.