how long did it take you to draw each of these, and did you use references?
a really useful exercise in nailing dynamic poses is to limit yourself to two minutes, one minute, even down to thirty seconds. when you start acting instinctively and making bold, continuous strokes to imply the body's shape and movement, the results can be really interesting. for example:

(credit to senshistock)
so the drawing looks kinda weird, and not like a human, but you start to get to grips with the feeling of the pose. from this you can build up through basic shapes into a finished drawing.

(forgive me, these are kinda naff and lotsa mistakes, i jus woke up :') )
you're off to a great start!! be sure to look at references, and there are lots of helpful youtube tutorials out there