Hey!
Your drawings are excellent at capturing the movement of the character, I can certainly feel it when I look at them. If you want to improve anatomy with gestures, I suggest blocking out broad shapes of the body (hips, rib cage, etc) and comparing the sizes of these objects with limbs, etc. Also just as important with the line-of-action are the relationship of limbs. For example, if someone were to do a pull-up, their lower body would stretch significantly due to gravity, but the upper body (esp the neck area and such) wouldbe squashed together.
Keep up the great work!
