I am quite thoroughly bruised along both arms. And I have lumps on my head. In my opinion, nuwishas_tail hits way too hard, but I come from a school of martial arts where you do not want to waste momentum on over committing to cuts and where misplaced strikes can infact lead to broken bones.
You learn fairly early on that the centifigal force of a two meter long weapon will lead to pain, so you learn accuracy is your friend. You also learn that swinging about wildly will only lead to missed targets, and pain. And possibly broken bones.
Do not strike until you know there is an opening (by forcing an opening or when your opponent opens one themselves), and do not waste your strike by getting it wrong - every strike should be a perfect cut. Perfect form, perfect accuracy, perfect tension of the strike, and the ability to respond once more should that strike fail - a balance between strength and flexibility.
This is how I look at shiai.
I am very, very tired. Too much stress, emotional trauma and work over too long a space of time will do that to you.