While there may be exceptions, the measurements noted are generally defined as--Constantly: 5.5+ hours per 8-hour day; Frequently: 2.5 - 5.5 hours per 8-hour day; Occasionally: 0 - 2.5 hours per 8-hour day. Occasionally sit, walk, reach overhead, reach at shoulder, reach at knee, reach at floor, bend, stoop, squat, crouch, kneel, stair climb, pivot.