The problem is that anatomy and motion or flow or force--should be studied separately.
Anatomy is great--but it can be the thing that prevents you from drawing motion and bring stiffness to your drawing. If you want to capture motion--you should try to not be too tied to getting detailed anatomy. Of course, your first few sessions wont be great--but thats the point. You fail so that you can succeed later.
Just look at my 30sec drawings--I wasn't too worried about anatomy here.
https://imgur.com/a/v4WOHwS
And for comparison, here are my most recent 2min drawings. Here, because I set up some fundamentals with motion, I could get both motion and some anatomy in.
https://imgur.com/a/7V5d0up
2min drawings, 1min drawings, 30sec-- the point of the short drawings are to force you to draw the overall form.
Also, like the previous comment, sometimes its great to change focus and come back later. You can draw other things, do other things. Sometimes you need a break.