Hi Cyrilpdev!
I really like your drawings and I could never draw in the same way. Critique end.
Just kidding, I skimmed through the tutorial, so let's get to the real critique. ;') (What I said before is still right though)
You got a great flow in your lines and I think you do well at getting grip on how the human body works. I get the impression your style works better for women or you practised female anatomy a little more. Anyways: I'd take a look at male anatomy here and try focus on how angular and blocky the male body is. Especially around the hips and arms, your figures seem a little clumpy. A good way to practice drawing arms is to imagine them as a chain.
For the muscles and stuff, I'd take a look at the masters (Michelangelo, Bernini, Raphael, etc.) and how they practised. Imo you are at a point, at which you could dive right into getting a few more details into your work!
You do a great job on simplifying the human body and on keeping your lines clear and not too scribbly! Though, I'd accentuate muscles and details a little more.
That's about it. You're doing great! Keep on that amazing work bud!