Check: Your Move Silently
check is opposed by the
Listen check of anyone who might hear you. You can move up to one-half your normal
speed at no penalty. When moving at a
speed greater than one-half but less than your full
speed, you take a -5 penalty. It's practically impossible (-20 penalty) to move silently while running or charging.
Noisy surfaces, such as bogs or undergrowth, are tough to move silently across. When you try to sneak across such a surface, you take a penalty on your Move Silently
check as indicated below.