This is a drawing made in 1 minute, part of the directed study from the human anathomy lecture about movement. I've picked up to go into a local pub and tried to sketch really fast some postures as told in the lecture.
I started off by building the axis, and drawing some smooth lines to get the right shape. After that I tried adding some details to my drawing, such as adding in a chair, and even clothes, to make it look more natural.
Another detailed sketch of mine regarding postures, I had a female model to change from a position to another so I can sketch out the poses. Similar to the first drawing, I started by doing the construction lines smoothly just so I can get an idea about how the angles made by the body are going to define the poses. Towards the end, I finished the sketch by adding details, such as shadows and a more organic look to my character.