I have to say I just don't understand why parents think physical punishment is necessary. I was never spanked. I was never even grounded. My mother would simply talk to me. And believe me, I listened. I loved her, respected her, and would feel terrible if I disappointed her.
My friends who got spanking and groundings and physical threats were much worse behaved than I was. They were the ones trying to get me to do bad things, like experiment with cigarettes. My mother worked full time, so I was home by myself from the time I got home from school until the time she got home from work. I could have done awful things with all of the freedom I had. But the 'bad' things I did included things like getting a friend to sneak a truck load of horse manure into the yard so I could use it on my garden in highschool (mom didn't like the smell of manure). Not even that bad, really.
I have seen kids chased about the house with a wooden spoon by their mother. What it looks like to me: an out of control adult, terrified kids, no calm communication. Oh, and no change in behavior from the kids. They might be cowed for an hour or two, but then they go right back to being out of control.
I don't train my dog with hitting either - I try to be calm and fair. And he comes when called, pulls a cart, does tricks, sits and waits and the door until I say "o.k." to go outside... and he doesn't cower when I raise my hand, the way some dogs who are trained with hitting do. That's the kind of relationship I like, with kids or dogs - fun, fair, firm when necessary and emphasizing strong communication.