CHARACTERIZATION OF WALKING STRATEGIES DURING SLOPE AND STAIR TRANSITIONS
Open Access
- Author:
- Sheehan, Riley Clifford
- Graduate Program:
- Kinesiology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 27, 2010
- Committee Members:
- Jinger Gottschall, Thesis Advisor/Co-Advisor
Jinger Gottschall, Thesis Advisor/Co-Advisor - Keywords:
- Strategies
EMG
fall risk - Abstract:
- Slope and stair walking are common, yet challenging, tasks which we encounter everyday. In addition, we are constantly transitioning between these walking tasks in a safe manner. Both slope and stair walking require modifications to force production, joint range of motion, and muscle activity from the normal level walking patterns. The overall goal of these studies was to determine the walking strategies involved in slope and stair walking, as well as the transitions between them. More specifically, I first sought to better characterize the fall risk associated with slope and stair walking as well as determine if transition steps are more or less risky than steady state steps. Second, I wanted to characterize the locomotor strategies used to safely transition between different locomotor tasks. To achieve these goals, I recorded kinetic, kinematic, and electromyography data while participants performed various walking tasks. These tasks included level walking, stair ascent and descent, and upslope and down slope walking at 4 different slopes (7°, 15°, 23°, and 31°). I collected not only steps on just the slopes and stairs, but also the transition steps onto and off of the apparatus, and 2 steps from the transition. To quantify the fall risk of these different steps I created a locomotor risk index which combined variables related to fall risk. Based on this index, I determined that transition steps have a greater fall risk than level, slope, and stair walking alone. By comparing the joint angle and muscle activity patterns of the transition steps to steps on the surfaces being transitioned between, I found that transition steps are not simply a midpoint between the two, but are more similar to a step on the new surface. This means that we are anticipating the demands of the new surface. I also found that these anticipatory changes are occurring at least 2 steps from the transition and that they scale with the demand of the new surface, i.e. angle of the slope. Overall, transition steps are a unique balance between the demands of the two surfaces being transitioned between. This leads to adaptations to the forces, joint positions, and muscle activity which may be related to the increased fall risk associated with transition steps.