prone 'jump up'
When you get tripped or bashed in combat, your position is set to "resting". While resting you heal faster, but your combat options are extremely limited. You cannot cast spells, and most active skills cannot be used either. In addition, you suffer a 25% penalty to your attack rolls. Standing up from prone provokes an attack from every opponent targeting you. Each round of combat there is a chance you will automatically leap up into a fighting position, without provoking an attack of opportunity. The jump up skill increases this chance.