Not every child responds to pain as punishment. =/ I was a really active kid so I ended up hurting myself all the time anyways (on accident of course) and I have a high pain tolerance, so had my parents taken the physical approach on punishments I would probably have just become bitter rather than be too afraid of getting spanked. But I know that's not true for every child, which is why you have to adapt accordingly to your child's needs.

For instance, my parents tried using the "go to your room" punishment for a while, which was really effective for my brother who craves attention and social interaction, but was completely ineffective for me since I would just go in my room and play with toys like I usually would.