Hello, I'm pretty new to the site, but drawing the torso is probably my favorite thing to draw :) Your quick sketches seem ok, but you say you're not seeing progress despite practicing a lot. I'm curious if you only do quick studies. I find it best to alternate quick sketching sessions with longer, more focused ones. Maybe taking more time to study a single picture could help you figure out the shapes better. I like studying bodybuilders as it's really obvious on them how the muscles work together.