If you're over-encumbered you walk slow as hell - we all know this.
I found out the other day while playing that if you're over-encumbered and manage to get both of your legs crippled - you walk noticably faster even though you're over-encumbered with a terrible limp.
Through first and third person you can notice you move faster. Just by the speed you're moving with 1st person and with the speed and animation in 3rd person.
It actually makes being over-encumbered bearable.. but it could probably use some fixing.