just be careful of trapping/breaking your own hands in an attack. Punching certain areas of the chest etc can result in a "reflex headbutt" from the opponent, or your hand getting trapped. A lot of people will have a reflex to pull their elbow back when hit (especially around their ribs), so make sure your fist isn't striking anywhere in that region, or it will get broken/trapped. Just a few things worth considering that don't necessarily manifest themselves in sparring, particularly if all your sparring partners have conditioned themselves not to perform these "reflexes"