Q: Pronation or Supination – how to tell the difference with the data? – JxRx

A: Pronation excursion (FS-MP) is the measure of how much roll the foot experiences between footstrike (FS) and the point of maximum pronation (MP). MP usually occurs before contact time is on average around 300ms. Similarly Pronation Excursion MP- Toe Off (TO) is the amount of roll the foot experiences between maximum pronation and TO. So what does “roll” mean in terms of pronation/supination? One way to think about these angles is to draw a line between your mid heel and 2nd metatarsal. The roll angle is measured as the rotation around that line. Inward rotation (eversion) is negative and outward (inversion) is positive. Another way to think about it is if your foot is on the ground and you pronate, your arch tends to flatten. – RS