Hello voxfour!
I'm sorry I wasn't able to get to your topic sooner, I've been on sick leave and was unable to check in here before. I hope Nikki.May's and my posts will still be helpful to you though!
Nikki.May raises excellent points. I don't know about Proko, but the site itself also has a couple of articles on gesture drawings that are useful:
https://line-of-action.com/gesture-basics-1-line-of-action/
https://line-of-action.com/gesture-basics-2-torso-and-hips/
https://line-of-action.com/gesture-basics-3-joints/
My main recommendation is to try and draw everything in less strokes. Instead of multiple strokes (even back and forth motions) to draw the spine, try to draw the spine as one line, from A to B. It probably sounds silly, but it'll give your strokes more confidence and strength! :) It'll really make the motion pop out more.
Please let us know if you need more help. I will be around more frequently from here on.
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