Torsional forces commonly happen during running, and their increase is believed to be associated with higher injury risk.
The measure of such forces during the stance phase of the gait is called the free moment.
Free moment can be described as the resistance to toeing out when the foot is fixed to the ground.
For instance, higher free moment has been reported to be leading to a higher risk of tibial stress fracture.
An externally rotated foot – overpronated – can increase the free moment, too. This is often linked to modifiable factors like reduced hip internal rotation, or hip external rotators strength. Nonmodifiable factors include femoral head anteversion.
Measuring the free moment requires specific equipment, like a force plate. If you do not have access to this, we can identify flaws in the kinematic chain by filming you running on the treadmill.
