Falls are identified as the largest risk and leading cause of injury for multiple populations, including young adults and individuals with a transtibial amputation. Furthermore, obstacle crossing is identified as the number one cause of a trip, which subsequently leads to falling. Previous research provides conflicting results and a lack of specificity in certain outcome measures of dynamic stability during obstacle crossing. Therefore, the purpose of this thesis was to gain foundational knowledge on outcome measures related to dynamic stability during an obstacle crossing protocol. An additional purpose was to investigate the dynamic stability of young adults, and speculate on the dynamic stability of a transtibial amputee following the same protocol. It was hypothesized for both young adults and the transtibial amputee, as obstacle height increased, the medial/lateral distance of the COM-BOS relationship will decrease, the medial/lateral distance between the COM-COP will increase, and that there would be increased variability in both peak and regional pressure of the trail limb during single support. Twenty young adults (aged 24.3 ± 2.9) and one transtibial amputee (age 27) completed six trials of level ground walking and 18 blocked and randomized trials of obstacle crossing at three heights (5 cm, 15 cm and 25 cm). Outcome measures for this study included:​ minimum and maximum medial/lateral COM-BOS, minimum and maximum M/L COM-COP, peak total and peak regional pressure distribution, step length, step width, and minimum toe clearance. A series of repeated measures analysis of variance (ANOVA) were performed on the young adult data, whereas the transtibial amputee results were interpreted based off of mean and standard deviation values. As obstacle height increased the minimum medial/lateral (M/L) centre of mass (COM) and centre of pressure (COP) distance significantly decreased (p<0.0001), total peak pressure significantly increased (p<0.0001), and pressure in the heel, lateral midfoot and toe regions of the trail limb significantly increased (p<0.0001) for the young adults. Furthermore, minimum toe clearance (MTC) was significantly lowest at level ground walking, while largest at the 5cm, and then significantly decreased as obstacle height continued to increase (p<0.05). Finally, step length significantly increased compared to level ground walking (p<0.0001). Conversely, the transtibial amputee showed lower total peak pressure, smaller step width, COMbase of support (BOS), COM-COP, and MTC distances. Ultimately, the results indicate obstacle height significantly influenced COM-COP, total peak pressure, regional differences in pressure, MTC, and step lengths of the young adults. Secondary interpretation of the transtibial amputee shows that the individual utilized a less conservative strategy and was therefore less stable compared to the young adults. Even though this individual was less stable than the young adults, he was still able to maintain enough dynamic stability during level ground walking and obstacle crossing tasks to avoid tripping and/or falling. This thesis further provides novel information regarding plantar pressure distribution both holistically and regionally for both young adults and an individual with a transtibial amputation during an obstacle crossing protocol.