In general I don't think studying how the forms of the body fit together and affect one another is ever a waste of time. There are some really good tutorials on this site about simplifying the shapes then working toward more detail and realism. For me I think studying how the forms join together is really key. What I mean is, for instance, how the muscles from your feed all the way to your head weave together into a single mass that moves together. This idea was driven home for me, ironically, when I was still a runner and went for a sports massage after an injury. The therapist showed me how (and why) an injury in one place can cause a secondary injury in a seemingly unrelated place. It clicked for me then how the muscles fit and work together. You can apply the same concept as Reilly rhythms to the entire body. I also find that doing quick gestural sketches can help with more natural-looking forms as well. For a great demonstration of working this way look at Karl Kopinski's or Kim Jung Gi's work. They start with sort of rough gestures and fill in the details right on top. Sorry for the kind of meandering answer. My mind is kind of spent after a long day punching code but I hope it helps somewhat.