Kai's Project Page

Who:  I am from Reno, Nevada and committed to the University of Utah right after I toured because it felt like home. The incredible engineering programs, ACCESS and opportunities for research, and the beautiful outdoors are major bonuses. In my limited free time I enjoy skiing, reading, and hammocking.

My scientific/engineering interests:  My diagnosis with Celiac Disease was the beginning of my interest in medicine and science. That was in second grade, so over the next ten or so years I researched various STEM disciplines. Biomedical engineering is creative and technical, developing new technology to help people in a number of ways. Quickly learning that I cannot stand examining internal organs, blood, and tissue, I discovered an interest for prosthetic devices.

Academic goals:  I am majoring in biomedical engineering with a mechanical emphasis, and plan on pursuing the BS/MS degree here at the U. My work in the bionics lab has allowed me to explore this interest further. The experience has been incredibly valuable, and I have learned so much.

Career goals:  In the future, I want to work on developing prosthetic devices, and am especially interested in pediatric prostheses.

Lower limb powered prostheses aim to support amputee mobility by attempting to match physiological movements of an intact limb. To accomplish this goal, powered prostheses provide assistive torque at the joint level in response to the user’s movements. The joint torque of the prosthesis must closely match the torque produced by the biological leg throughout an activity. The biomechanics analysis of non-amputee individuals provides a necessary reference to optimize the assistance provided by the powered prosthesis. As various activities are performed, biological muscles produce torque that can be used a reference for the level of assistance required by an amputee. However, the relationship between muscle activity, joint torque, and assistance for many common activities is still unknown. Here we show that the relationship between knee torque and hamstring electromyography (EMG) signal is linear and consistent during standing activities such as sit-to-stand transitions, lunges, and squats. We recorded the joint motion, joint torque, and muscle activation (EMG signals) of two non-amputee individuals. Each individual performed sit-to-stand transitions, lunges, and squats. Motion capture data analysis was performed with Vicon Nexus, Visual3D, and MATLAB. Our results show that the linear relationship between hamstring EMG and knee extension torque is consistent across all activities and between non-amputee individuals. This analysis suggests that hamstring EMG signals can be used to control the knee extension torque of a powered prosthesis to support all standing up activities. Implementing the relationship between hamstring EMG signals and knee extension torque as a control strategy for powered prostheses has the potential to make the device more intuitive, safe, and user friendly.

The Relationship Between Knee Torque and Muscle Contraction for Powered Prostheses Download The Relationship Between Knee Torque and Muscle Contraction for Powered Prostheses