Knee kinematic and kinetic characteristics of landing after hop : ACL injured subjects before and after rehabilitation

BACKGROUND: Dynamic knee stability strategies of anterior cruciate ligament deficient (ACL) subjects have previously been reported in gait analysis studies. Few studies have investigated these strategies during a more strenuous sport related activity such as a single leg hop. Joint stiffness may be an important functional performance parameter, to our knowledge no one have looked into knee joint stiffness after an ACL injury. Furthermore, too few studies have examined changes in dynamic knee stability strategies after an ACL injury and a specific rehabilitation program. OBJECTIVES: The purpose of this study was to elucidate different movement patterns, in the lower extremity, and knee joint stiffness of injured compared to uninjured side, during landing after a single leg hop in ACL injured subjects classified as non-copers, before and after a 20 session rehabilitation program