In the case of disabling blows to arms, participants no longer utilize the arm. Shoulders count as Torso. Legs strikes do not require the fighter to sit, fall, kneel or lie down. They may continue standing and fighting, but must restrict their movement to limping. Hips count as torso.
All hits depend on the honor system.
If in doubt, ignore a hit. The defender gets the benefit of the doubt. Next time hit them better. All hits should be acknowledged by the defender, unless it was obvious to both parties. If you feel you made good contact and your opponent says nothing, then question it.