In first excuse my english...
So I think the legs are too short. I think is better to draw the legs a bite too longer than shorter.
The arms should arrive to the half thigh.... so they are a bit too short too, but it's not problematic like legs....
The pelvis itself is more of a rhombus like shape rather than a circle/sphere. Thinking more about how the anatomical structure is shaped while gesture/ figure drawing will improve your knowledge of how the human body works. In terms of the gesture of the pose, I feel like you nailed it down! I can see what the essence of the pose is and approaching your lines in a fluid manner, thinking about directions and looseness. The next step would be just continued practice as well as utilization of CSI lines. Also something to think about, think more about the directions that the pose is making and less about the contours of the body. The limbs, for example, show that you're too consious about the contours of the arms and legs and trying to render it in one go. Instead of that, think about the limbs as components or parts rather than one think. Overall, good job!
Here are some resources that may help you further!
Wow, some ability you display, DarkRou, but I've got two questions: 1) How long did it take you to sketch out those gestures. And 2) Why don't you do your first ever 5 minutes of 30 second actions, pretty please? The reason why is because, it'll totally loosen your hand up. Hope and pray that it'll work out for you.
Polyvios Animations, i set the timer for a 2 mins. Yeah, not so fast, but i did it like Proko advised. I know that i must work on it, but due to the fact that i practiced at gestures only 3-4 days, so i can't do it faster
Hey!! I love those curves. I'm not an expert but I've been studying 2D animation and practicing some anatomy lately. I'd suggest you trying not to use circles or round shapes for important parts of the body, like the chest or hips. Instead, try using triangles; they are more interesting shapes and they kinda fit better for sketching human figure. Keep doing like this, great work!