Players can change their position manually, though a number of things can force different positions on players or mobs. Being bashed or hit by the Earthquake weave will cause the target to sit, while the Sleep weave will make the target sleep. Other things such as falling off of a horse can cause similar effects.
List of Positional Effects
|Mortally wounded||-6 to -10|
|Incapacitated||-1 to -5|
1 - Offensive bonus and Dodge bonus are both reduced to 1 when Sleeping.
-  - WoTMUD Archives forum posting on OB/DB/PB testing