Values tested with Bizhawk using the ram viewer.
|Movement Type||Movement Value|
|Walking in Grass||30|
|Walking on Stairs||20|
|Swimming While Pressing A||40|
Note: Walking on Grass and Stairs slows you down, but if you jump over them, you do not slow down. Also, walking on ice works by starting out at 5, then increments by 5 every 5 frames.