My first idea would be: Use bigger paper. And more. Crunching all of a 30 minute class on one single page doesn't really help a lot in developing line quality and makes critiquing individual drawings a bit awkward.
In some of your drawings I had the impression, that you are not 100% clear about position and function of the hips, others look more competently. The five-minute sitting female's front leg for example doesn't really connect to the hip.
The gap between 1 minute and 5 minute drawings is a bit of a problem for me, too. I try to tackle it partially by taking a deep breath and concentrating more on placing the initial lines accurately.
Well, well, Sonnemaker, I must admire your 30 second-1 minute quick sketches, cause they're on the right track in terms of action and acting.
In the meantime, my critique is that your forms are a bit too wobbly and loose, despite the forces are a bit more bolder and broader, and overplaid. Would you kindly construct out the lines and spaces with 30 minutes of 2 minute quick attitude drawings? (15 of 'em)
The reason is as a result, you'd be able to improve your understanding of your body constructions and silhouettes, and lines of action. Good luck to you, and I hope you've found these completely and defintely beneficial.
I think you've got a good grasp of the forms, I assume these were done digitally so the comments about the size of the workspace probably won't be of much importance for you. I do think the line quality on some of the sketches is kind of... sketchy? I know these aren't meant to be perfect, obviously. But I think that practicing with a focus on the lines themselves would help. The second sketch from the top left (both of them really, the one to the right, and the one beneath it) I can really see the sketchiness in the feet, and the form/gesture get's lost.