This is extremely good I think! Wonderful sense of movement and proportions. I really like the way you have explored the various poses. Some of them are just too good! Just one thing I think which lacks is variety of proportions. I definitely encourage your to do a female version. It will not only be good for you but also for other artists for reference. Also, I think this is really clean! I can never do such clean stuff as far as practice is concerned*hehe*. Each of these can be taken for a full fledged drawing! Great Stuff mate! A wonderful resource it is.