I would recommend not working on gesture and muscle groups at the same time like this. As it was said, focus on proportion and balance.
The center of gravity is going to be directly between the feet if the figure is balanced on both feet. If the weight is shifted then the head is over the standing leg.
In my opinion, Hogarth's books are not helpful to a beginner. It's overly stylized and the exaggeration is unnatural. Of course, reading the theory is good, but I think there are more helpful books to buy first.
I find that drawing dancers and athletes is a good way to practice gesture.
I got this book and it was a great read. There's a lot about relationships and balance. When I recently took figure drawing, this turned out to be he recommended reading as well, so I already had it.
The Loomis books are good too. Art training gets expensive though, so if you have time, go to the bookstore with your sketchbook and a notebook and as you read, make yourself some notes. Copy diagrams into your sketchbook carefully, paying close attention to the proportions. (I'm recommending things that we did for my figure drawing class.) Most of all, don't just buy the book and then read it. Make sure it's something you feel will help you or it may get frustrating. I know that happened to me.
An open mouth and an open mind go hand in hand. - me