Fig. 2.

Single frame motion analysis. Representative single frames extracted from high-speed videos where individual frames were used to assess effective quadriceps function at specific points within each movement cycle. (A–B): The foot base angle (FBA) was measured at the point where the ipsilateral leg is at its highest point. (C–D) The protraction limb ratio (PLR) was measured when there is complete vertical extension towards the fixed object below. Measurements are taken prior to injury (A, C) and periodically during the first 15 weeks following injury (B, D).