I find it impressive that you can get a really strong motion down in just a few seconds for these figures. Great job on that! I can read the action, but it would be good if you could get more definition of the limbs' volume, instead of showing just lines for those. Drawing in the volume for say, the calves and forearms should help you make more detailed stuff down the road. Since this was a few second exercise, maybe try quickly sketch the shape (outline?) of the limbs with one continuous line.
THANK YOU for this comment!!! Totally true about the limb's volume, its a bit tricky tho, I've been trying it a bit, but some detail that blew my mind a bit was the CALVES detail, it gives more stability to my figure drawing helping more to understand the motion from the arms connected to the torso, and it lays an easy path for me to sketch the trapecious and the neck; such a small detail but it improves a lot my sketches, thanks for sharing that!!!