I've seen tons of sites claim that it takes only 7 kg (some say 7 lb) of pressure the human collarbone. That can't possibly be true, can it? Wouldn't we see collarbones being broken by the slightest tap in every match if it were? Any 10 year old kid can punch with 7 kg of force. Anyone know whether this is just some urban legend or if the collarbone is actually this magical glass bone that anyone can shatter with the lightest touch?