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fyang61
01-04-2006, 08:06 AM
Dear all,

Recently, we have been studying the relationship between the joint work and body mechanical energy during human gait. It is assumed that the changes in body mechanical energy should equal the work conducted by the body joints during the same period of time, such as from right heel strike to right toe off.

We only concern our model on the sagittal plane. The body mechanical energy includes the body potential energy, the body kinetic energy (horizontal, vertical, and rotary parts). As for the joint work, only the lower extremity is considered. The joint work is calculated as the integration of the net joint moment along the joint angle time history. The net joint moment was computed using inverse dynamics.

So far, the time histories of the net joint moment, joint angle, and the body energy are very similar with the results published by other researchers. However, the match between the joint work and the changes in body mechanical energy seems very terrible. The difference between these two sides is very huge. Even we checked our program and experimental data for a pretty long time, we cannot solve this problem.

Does anybody have the similar experience to handle this issue? Is the assumption mentioned above is correct? Or the total joint work and the changes in body energy are not equal to each other at all during gait due to some energy losses (e.g. collision, thermal energy dissipationˇ*)?

Any suggestion and reference will be deeply appreciated.

Wish you all the best in New Year.

Feng



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