Error with Ligaments in Static Optimisation

Giuliano Lamberto · Post by **Giuliano Lamberto** » Fri Nov 07, 2014 7:53 am

Hello,

In our lab we have been trying to run static optimization simulations of gait. However, when ligaments are included in the model the results are no longer realistic.

We have performed walking simulations with a modified gait2354 model (published in Xu, 2014, CMBBE) using the markers and force data provided with the original gait2354 model. Without any ligaments the static optimization works well and provides the results shown in attachment_1. However, as soon as ligaments are added the results become unrealistic. For example, when we include a single ligament with a resting length of 10 times the original resting length, the static optimization results are drastically different (see attachment_2). This is unexpected since the strain of the ligament is zero throughout the gait trial and so the results of the static optimization should be unaffected.

Any help in understanding this issue would be greatly appreciated.

Thanks,

Giuliano