It can not be denied that Michelangelo was an outstanding draftsman. He was empathetic. Just look at the pain or twisting or reaching out from his figures. Below I showed a very few that hopefully exhibits what I mean and will help students see how contour and gesture with keen observation yields great
Here in this sketch the lines and contour lines with the hatching describe the whole of the body, mass and weight.
The drawings above show the use of contour, the shape, the the addition of contour line with hatching start to bring the bodies to life
This feels more like a gestural study than a contour. The lines are quick. They give direction but do not really describe shape. In this one it feels more like Michelangelo was searching to find the figures.
What a Horse, now check out Michelangelo's chief rival Leonardo.
Drapery, you know you can draw realistically when the drapery has weight. Notice the hatching to describe the direction of the material or folds. Also the light is so delicately drawn that the clothe feels stiff but not not to stiff.
above, the gestures capturing the thinking of the master. now notice the scale of the writing and the scale of the drawing. the drawing is small, thumbnails size