This drawing clearly shows the balance and weight of the body and how it is all placed on the hands on the left of the drawing and the leg which is stretched out to the right shows the balance of the body. The posture of the body is very important as it conveys the balance of the body, this shows whether it is going to fall over or stand straight or lean etc.
The pose of the model clearly identfies what gesture he is making, the model is stretching out his leg to show he was relaxing and his hands show he is leaning to the left as that is where all his body weight is being held. You can clearly see the active and passive sides to the body which show the gesture that the body is making of stretching, these are the passive sides, where as the muscles are contracted and bunched are the active sides.