The purpose of this study was to analyze kinetic and kinematic data of individuals with unilateral transtibial limb loss and the effect different alignments have on the individual’s gait while they walk over uneven terrain. Individuals with lower limb loss are currently having their prostheses dynamically aligned to ensure a satisfactory walking gait on level ground with smooth surfaces, usually in the clinician's office or hallway. This study was looking to determine whether or not current prosthesis alignment procedures are adequate for determining a satisfactory walking gait on non-level and non-smooth terrains as well level smooth surfaces. An effective and efficient walking pattern is necessary to prevent degenerative conditions within the bones, muscles or other tissues of the body, due to compensations of the gait pattern. Sometimes, individuals are able to mask any compensations if their safety is unaffected by their surroundings and they are able to maintain a gait that appears normal or optimal. However, if terrains used on a daily basis present a sense of insecurity, gait compensations could be more problematic to the individual and they need to be addressed and corrected as best they can. This study determined that while there were some changes in gait on the uneven surface, due to the number of subjects it is unclear whether the changes are significant. The individuals showed a decrease in walking speed and step length and an increase in step width. There were also changes in the peak axial force.

The CAREN-Extended system is a fully immersive virtual environment (VE) that can provide stability-challenging scenarios in a safe, controlled manner. Understanding gait biomechanics when stability is challenged is required when developing quantifiable metrics for rehabilitation assessment. The first objective of this thesis was to examine the VE’s technical aspects to ensure data validity and to design a stability-challenging VE scenario. The second and third objectives examined walking speed changes and kinematic strategies when stability was challenged for able-bodied and unilateral transtibial amputees. The results from this thesis demonstrated: 1) understanding VE operating characteristics are important to ensure data validity and to effectively design virtual scenarios; 2) self-paced treadmill mode for VEs with multiple movement scenarios may elicit more natural gait; 3) gait variability and trunk motion measures are useful when quantitatively assessing stability performance for people with transtibial amputations.