This paper provides insight into the burden when people are walking up and down slopes in a virtual environment (VE) while actually walking on a flat floor in the real environment (RE). In RE, we feel a physical load during walking uphill or downhill. To reproduce such physical load in the VE, we provided visual stimuli to users by changing their step length. In order to investigate how the stimuli affect a sense of burden and body ownership, we performed a user study where participants walked on slopes in the VE. We found that changing the step length has a significant impact on a burden on the user and less correlation between body ownership and step length.