Abnormal Pronation - Observed in Rothbarts Foot

Referred to as Gravity Drive Pronation

Abnormal foot pronation refers to the timing of pronation.  That is, the foot is pronating when it should be supinating. 

  • The Term Abnormal Foot Pronation does not refer to the degree of pronation.
  • The degree of foot pronation is determine by the structure of the pelvis (e.g., the arc of its' rotation).  


Abnormal Foot Pronation.  In Rothbarts Foot, from Foot Flat to Heel Lift, the foot's motion is being driven by the pull of gravity, not by the Clockwise, Counter-clockwise rotation of the pelvis. ‚Äč 


Gait Analysis - Stance Phase Right Foot

From Heel Strike to Flat Foot, the pelvis is rotating Counter-clockwise 

  • This Counter-clockwise rotation pronates the right foot.  
  • The right foot is being driven by hip drive. 
  • Foot pronation unlocks the forefoot and allows it to adapt to uneven ground surfaces.


From Flat Foot to Heel Lift, the pelvis is rotating Clockwise.  

  • This Clockwisel rotation should supinate the right foot. However, the pull of gravity on the elevated first metatarsal and hallux, pulls the right foot inward and downward (e.g., continues the pronation) until the 1st metatarsal and hallux rests on the ground (See White Arrow).
  • The right foot has escaped hip drive and is now functioning in gravity drive (abnormal) pronation.
  • This abnormal pronation maintains the foot in an unlocked position (referred to as a 'loose bag of bones') and delays the resupination of the foot.
  • At heel lift to heel off, the windlass mechanism resupinates the foot.


References
    Zitzlesperger S 1960.The mechanics of the foot based on the concept of the skeleton as a statically indetermined space framework. Clinical Orthopedics, 16:47-63
    Rothbart BA 1973. Part I. Biomechanical analysis of a normal gait pattern.  Journal Canadian Podiatry Association, (3):3-7.
    Rothbart BA 1973. Part II. Biomechanical analysis of a normal gait pattern.  Journal Canadian Podiatry Association, (4):1-12.