Hey João, Your gestures are made up of flowing lines which shows the gesture but lacks dimension. They also are made up of lines that start and stop, meaning they lack gesture all the way through the pose. I took one of your gesture drawings and did a sketch over it that should show what I mean, I hope it helps :)

Your gestures are loose and seem pretty explanatory of what you’re seeing, so I would suggest adding 3 dimensional forms to your gesture drawings so you have to learn how to see gesture in simple forms rather than using just lines. That’ll most definitely give you a difference in feeling between the lengths of the intervals.  More time = more complex and descriptive Less Time = simpler and looser  Therefore  If you don’t have a defined personal goal of why you would need to practice these concepts it’ll be hard to see the differences. You’ll just be practicing gesture in general otherwise. So figure a way to add your gesture practice into what you would like to draw that's completely separated from the strictly educational aspect.