this is great so far! I love gesture drawings! I would recommend finding landmarks for anatomy on the inside of your figures--right now you have great landmarks for the silhouette, like the hips and the shoulders--but nailing the inner landmarks like the belly button, the nape of the clavicle, the V you get on your lower back (not all at once obviously because it's a short gesture). Those can create natural S curves across the front that can quickly define the volume of your figure and really help direct the action more and make them more 3 dimensional.
I'm not super great at explaining this, but basically inside stuff. Muscle stuff. You can draw the volume inside of your gesture more, so long as it's clean and not confusing.