I think these are a little stiff and could be more exaggerated. It’s very hard to not focus on the contour which I feel like you might be doing a little and just try to show the motion. Something that might help you do that is just try to see where the main motions are and where to exaggerate before you start drawing it.

Title should be "foreshortening"!

Yes. This way you can download the videos seperately instead of the whole 40min video.

#7 should actually be two different sketches!

I think they overall work and make sense from what I understand. The only critique I have is to work on improving your line quality. I'm noticing some heavy areas that have a little bit of overwork to them. I also am seeing you struggle a little with transitioning along curves, where you can see a start and stop when you hit a strong curve. I'm not perfect at ellipses either, but I think this lesson from drawabox may help you. https://www.youtube.com/watch?v=tHJ3rzk6kno

I'd recommend you focus more on the flow of the figure, Vilppu does it really nicely, it helps to see him draw here : https://www.youtube.com/watch?v=aOtVUHgJqQk&ab_channel=NewMastersAcademy

Reviewing your drawings I can see what you mean about having difficulty with the arms and legs. I'm wondering if you're trying to imbue too much detail in both the hands and joints. For instance the gesture on the far right I can see some definition of the elbow joint when really I should either by a sharp transition to show the tension or a smooth one. Instead, I have a feeling you're looking too much at replicating the contour vs the gesture itself. In other words, concentrate more on the main gesture and the feeling of the gesture vs getting caught up in replicating the details/contours.