Sorry to go into a big tangent about swordfighting in your thread, but its something i'm super nerdy about
If the sword was really THAT heavy, there would be no way to move your body effectively behind it -- imagine trying to chop someone apart with a 50 pound barbell. You would get annihilated. For those clean, smooth, samurai style strokes it's all about the footwork and posture of the fighter behind the blade. Swordfighters move a lot like boxers -- the sword glides, and the fighter needs to be able to evade or block or riposte or circle his opponent or what have you after or during the strike, so you usually see that tight, almost sideways footwork.
An artist who captures this fairly awesomely very often is Takehiko Inoue in Vagabound
, which is full of awesomely drawn and characterized swordfights. See how clumsy he makes the two fighters in white look, just by drawing them 'chasing' their swords?
Another REALLY AWESOME reference is the Dog Brothers footage -- They're a loose group of mma fighters, martial artists, and knife fighters interesting in maintaining full contact weapon based martial arts. Devolves into wrestling a lot more than a fight with a real bladed weapon would be, but is still fantastic reference
for what kind of movements it takes to bring weapons to bear with force and accuracy.
So in conclusion, basically, how much your drawing deviates from 'good' form for swinging a weapon makes your fighter look extremely wild and clumsy and reckless... Which completely works, as characterization!