I really like the "life" in these. I have a tendency to get lost in an aspect of a pose and forget I only have a short while to capture the sense of movement or rhythm. I get a sense that happened here and as as reult you where working too tightly in the first few of these and at the same time tried to capture too much inthe time allowed.
Your sense of proportion is great, and in longer poses you have added nice shading. A good exercise might be to warm up with the short pose, use the same pose for the next longer session, and then (using the same pose) really allow yourself time to develop what you learned in the first two exercises. Doing the same pose in seccession will open up the work, while allowing to you to ultimately build out some detail. A couple of these would be great starts to a full study! Nice job.
I think you're being too hard on yourself. You have captured a nice sense of each pose in the quick sketches. The third set of studies is nice. I think every artist sees the set of shapes differently and it's often a matter of finding what works best for you. The key is to focus on how the shapes you chose to use work in relationship to each other. I often use aseries of quick lines to give me a sense of the general flow, and then build the shaps working along the axis I've laid out. That seems to work for me. In the first two studies I think the proportion is a little off, and that skews the overall perspective. SOme of these poses are tough when there is not a sense of how light and shadow is working across the figure. you might try playing with the addition of some basic values - that can really change how perspective and proportion are rendered by the eye. Keep it up!
