Bad Leg (3.5e Flaw)
From D&D Wiki
You have a bad leg, which slow you down a bit and make it awkward to run. If you fall though, you will feel it.
Prerequisite: Must have legs or limbs for locomotion.
Effect: You take 50% extra falling damage and your land speed decrease by 5 ft, additionally when you take the Run action you only move three time your speed (or twice your speed in heavy armor or while carrying a medium load or heavier). You take a -4 penalty against being tripped, bull rushed or otherwise moved against your will.