The purpose of this study was to investigate the kinetic and kinematic effects of load carriage while wearing a robotic transtibial prosthesis. Nine separate tests were conducted with a unilateral transtibial amputee test subject wearing the robotic foot-ankle prosthesis. The subject walked on a treadmill at 1.3 m/s with a back pack weighing 0 kg, 4.5 kg and 9 kg. Direct measurement of the kinematics and kinetics of the robotic prosthesis at varying loads and ankle joint stiffness using embedded sensors is presented. The test data suggest that the coping strategy for load carriage is one of kinetic variance and kinematic invariance for subjects using a powered, computer controlled foot-ankle prosthesis. The finding suggests that modulation of the spring stiffness as a function of load condition may reduce system energy expenditure by 10%.