Some think that the Hoshanos beating is supposed to sound like a huge downpour. So you need to hit it hard but not constantly beating. They should be hit 5 times, not more. Al Pi Kabalah there is an Inyan to have some leaves fall off. I often beat it 5 times into the ground moderately hard. If no leaves fell off, I pluck two off with my hands and then pick them up before I leave Shul.
