Undergraduate Honors Theses

Thesis Defended

Spring 2017

Document Type


Type of Thesis

Departmental Honors


Integrative Physiology

First Advisor

Dr. Alena Grabowski

Second Advisor

Dr. Jana Jeffers


In healthy adults walking on level ground at a steady speed, the ankle plantar-flexors provide the majority of the push off work necessary to redirect and accelerate the CoM during the step-to-step transition. People with a transtibial amputation lack these muscles, compensate for the lack of powered plantarflexion with more proximal muscles, and exhibit biomechanical asymmetries when using a passive-elastic prosthetic foot. Use of a biomimetic powered ankle-foot prosthesis has resulted in normative metabolic costs and biomechanics during walking in people with a transtibial amputation compared to non-amputees. Therefore, use of a powered ankle-foot prosthesis likely affects leg muscle activity, but these effects are currently unknown. We investigated changes in activation of the gluteus maximus, gluteus medius, rectus femoris, vastus lateralis, biceps femoris, tibialis anterior, soleus, and lateral gastrocnemius muscles of the affected and unaffected legs of 10 people with a unilateral transtibial amputation using a passive-elastic and powered ankle-foot prosthesis during level-ground walking at 1.25m/s. We hypothesized that peak muscle activation and integrated electromyography (iEMG) would decrease in the unaffected leg, and increase in the affected leg. Peak muscle activation was greater in unaffected leg gluteus maximus, rectus femoris, lateral gastrocnemius, and soleus while using a powered prosthesis compared to passive-elastic prosthesis (p<0.05). There were no changes in affected leg peak muscle activation or iEMG in either leg with use of a powered compared to passive-elastic prosthesis. Though use of the powered prosthesis did not reduce unaffected leg peak or iEMG, or increase affected leg peak or iEMG, other biomechanical changes may be responsible for overall increases in leg muscle activation.

Included in

Biomechanics Commons