Model and measurement studies on stages of prosthetic gait.



In the current thesis ’Model and measurement studies on stages of prosthetic gait - Predictions on how not to walk symmetrically with a mechanical prosthetic limb’, we reported predictions, outcomes and insights gained from studies in which we investigated how transfemoral (TF) amputees compensate for the limitations in the active control of the orientation of the ground reaction force (GRF) and the position of its origin, the center of pressure (CoP), during gait initiation and termination, and the absence of active knee extension control during weight bearing on the prosthetic limb. Also, we reported which strategies contribute to successful prosthetic limb forward swing during obstacle avoidance and what should be taken into account during obstacle avoidance.
We used mathematical models to investigate principles of TF amputee prosthetic gait in four specific stages, namely gait initiation, weight bearing, prosthetic limb swing and gait termination (figure 1). For every stage, a mathematic model was designed which allowed us to analyze in a conceptual world phenomena we have observed in the real world 1. Data of TF amputee and able-bodied (AB) subjects using a knee walker prosthetic device were used to validate the models that were all checked for (internal) consistency, conservation of energy and realistic parameters. The four stages were described in separate chapters in this thesis.
The findings were used to increase our insights and contributed to the development of our theory on TF prosthetic gait. The predictions of the models changed our thoughts on certain choices in strategies that are made when using prosthetic limbs. These models can be of interest when forming new ideas about how to improve prosthetic knees and feet and how to improve rehabilitation programs.


Figure 1: Four models that were used in this thesis to study specific stages during gait: gait initiation, weight bearing, prosthetic limb swing and gait termination.


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