As I mentioned previously, I'm planning on having the character "run" when the player is standing normally and "walk" when player is crouching slightly. The only movement speed factor remaining is "sprint".
"Lean forward + D-Pad Up" will therefore become "sprint".
NOTE: The above example is "stand and sprint", but you can also "crouch and sprint" by ducking low and leaning forward. "Crouch and sprint" is slower. Also notice that "leaning forward" is bound to "optical zoom" when the D-pad is not pressed.