The Hip: Preservation, Replacement and Revision

Heel Off Phase of Gait

- Discussion:
    - at heel off the resultant force passes in front of the knee and acts to extend the joint (hyper-extension moment);
    - as resultant forces passes in front of metatarsal heads, knee joint flexes & mechanical forces act in direction of flexion once again;
    - knee has extended to approx 178 deg;
    - is probably being initiated by the biarticular gastrocnemius which is also helping to prevent hyperextension of the knee from occuring;
    - peak electrical activity of gastrocnemius occurs shortly after heel off;
    - since mechanical forces are acting to extend knee at this time, and since hamstrings are inactive, it is reasonable to assume that gastrocnemius is helping to prevent knee hyperextension

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, May 24, 2012 1:00 pm