Groundings usually only work if a child respects their parents and their decision. Ultimately, it is how you raise the child. Instead of telling them what they shouldn't be and what they shouldn't do, you should show them what they should be doing. The best parents are usually those that don't advocate "Do as I say, not as I do" (That isn't to say these parents are bad, though), but instead try to set an example. And that includes admiting to when they are wrong and apologizing when they make a mistake. Hitting may work for some children, but for others they connect pain not with the action of what they did, but instead with the parent. Some don't see it as a form of punishment, but rather a call of dominance, the parent basically telling the child to obey their whims or they shall feel their wrath. :/