Hello there! Exaggerating proportions doesn’t really affect the shading itself. What would affect it is not understanding the volume of the body and, as a result, not shading according to the forms. As for your painting, you only need to adjust or define the shadows a bit more in certain areas. For example, notice how there should be some ambient occlusion around the shorts, where the foot overlaps the leg, slightly underneath the armpit, and in other areas where forms are pressed together or receive less light. There are also a few areas that could be pushed slightly darker, such as the side plane of the torso and the extended leg. Honestly, there isn’t much else to add. Just pay close attention to the value of your shadows, since they play a huge role in defining the volume and solidity of the forms. Hope this helps!
