Mechanical energy fluctuations during walking of healthy and ACL-reconstructed subjects.

In a clinical gait analysis, mechanical energy is the gait variable which can validate the energetic state of the disorder of patient's movement. The purpose of this study was to explore the possibilities of employing the total mechanical energy in estimating the mechanical cost of transport in normal and pathological human gait. One of the basic methods of determining mechanical energy (inverted pendulum model) was used to estimate the external mechanical work performed by the walking subjects based on externally observable measurements. Gait data was collected for healthy able-bodied men and patients after ACL reconstruction during physiotherapy process who demonstrate larger lateral center of gravity (CoG) excursions during gait. Based on predictions of the body's CoG trajectory during walking, algorithms were developed to determine the changes in components of total mechanical energy in normal and pathological gait. The utility of calculating mechanical energy in a patient population is questioned.