Run( Player's Handbook v.3.5, p. 99)
You are fleet of foot.
When running, you move five times your normal speed (if wearing medium, light, or no armor and carrying no more than a medium load) or four times your speed (if wearing heavy armor or carrying a heavy load). If you make a jump after a running start (see the Jump skill description, page 77), you gain a +4 bonus on your Jump check. While running, you retain your Dexterity bonus to AC.
You move four times your speed while running (if wearing medium, light or no armor and carrying no more than a light load) or three times your speed (if wearing heavy armor or carrying a medium or heavy load), and you lose your Dexterity bonus to AC.