THE UD_POWER Link Model Based item computes the unified deformable power at the distal end of foot (or shank). It replaces the old command Compute_UD_Power.

Anatomically-relevant biomechanical models have traditionally been used to quantify joint powers and segmental energies of lower extremity structures during gait. While these anatomically-relevant models contain a series of rigid body segments linked together via mechanical joints, prosthetic below-knee structures are often deformable objects. Additionally these below-knee structures may not have a definable ankle joint. As a result, applying anatomically-relevant models to the study of prosthetic limbs has been problematic.

Takahashi et al (see reference) developed and validated a unified deformable (UD) segment model for quantifying the total power of such below-knee structures. These estimates of total below-knee power derived via the UD segment model were found to achieve similar results compared to below-knee power values derived from an anatomically-relevant model during gait for eleven healthy subjects. Differences in peak power, total positive work, and total negative work were also comparable to the values derived from the anatomically-relevant model. The UD segment model, however, does not require the definition of an ankle joint or foot structures. This technique may therefore be useful for users who are looking to directly compare anatomical and disparate prosthetic below-knee structures.

Takahashi KZ, Kepple TM, Stanhope SJ. “A unified deformable (UD) segment model for quantifying total power of anatomical and prosthetic below-knee structures during stance in gait.” J Biomech. 2012 Oct 11;45(15):2662-7