Whilst in the US I took with me a book about figure drawing which encourages you to break the body down and begin with a basic framework that you focus on getting proportionally right. It encourages you to try to pose the figure in different ways to convey emotion and to look at what that does to the limbs etc. Below are some examples I did on the plane.
After we arrived at the ranch where we were learning sword fighting for our charity performances, the training workload was such we had little down time and what there was my brain needed as rest. I did manage two brief A5 drawings from life using the above method when my husband was running through sword parries with our wonderful host and coach, Anthony De Longis. As I tend to draw face portraits rather than full bodies, this was useful practice although I am not sure how valid the approach is.