Why This ???

Info from Summit

"Running vs Walking"
You may be wondering why you would want to walk instead of running everywhere. When you are running, any melee monster within range will always hit you. If you were to run into an arrow or any other missile that doesn't automatically hit, they will be auto-hit then. By running near melee monsters, you leave yourself vulnerable to attacks. However, when you are walking near monsters, the normal chance to hit, determined by your Dexterity, your character's level, etc., will apply. You might want to return to walking when facing monsters, especially if you're using a class that relies on melee attacks, like the Barbarian, Paladin, and, at times, the Amazon.

When you are running, there is a slight chance that a monster's attack will hit an area that you have already run past. While there's a good chance that you will get hit, it's not absolutely certain. If you find you're getting hit too often while running, try walking for a while.

Since melee monsters will almost always hit you when you're running, classes that need to run a lot don't need to worry too much about Defense stats. In the later Acts and at higher levels, Necromancers and Sorceresses need to run a lot to evade groups of enemies. These classes should use shields to increase their odds of block, rather than focus on Defense. "