You move five times your normal speed while running 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 Acrobatics), you gain a +4 bonus on your check. You retain your Dexterity bonus to your Armor Class while running. Associated Movement Mode: Ground. Associated Skill: Acrobatics. Associated Feat: Run.
You can run as a full-round action. If you do, you do not also get a 5-foot step. When you run, you can move up to four times your speed in a straight line (or three times your speed if you’re in heavy armor). You lose any Dexterity bonus to AC unless you have the Run feat.
You can run for a number of rounds equal to your Constitution score, but after that you must make a DC 10 Constitution check to continue running. You must check again each round in which you continue to run, and the DC of this check increases by 1 for each check you have made. When you fail this check, you must stop running. A character who has run to his limit must rest for 1 minute (10 rounds) before running again. During a rest period, a character can move no faster than a normal move action.
You can’t run across difficult terrain or if you can’t see where you’re going.
A run represents a speed of about 13 miles per hour for an unencumbered human.