Hey there SpiritDreamer,
I like that you are working on some nice dynamic poses in your scenes. Something I noticed however, was the placement of the feet in your knockout boxer. If you are delivering a powerful punch like that, (and granted I am not a boxer ) your feet would not be together like you have them here. That fighter looks as if he is about to fall on his face. You need one leg out in front for balance. I would encourage you to stand in front of a mirror or have someone pose for you and just watch how they would naturally stand and where the weight is placed.
Also, on the placement of the figure on the ground. You are starting to get some nice follow-through with rotation of the torso of the main fighter but it looks like he hasn’t actually hit the spot where the other figure was standing before he was knocked out. Does that make sense? The fighter on the ground needs to be visually further back in space to convince the viewer that fighter B was just hit by fighter A.
I hope that helps. Looking forward to seeing what happens and good luck!