Standing Man

It looks like you're really trying to study the anatomy of the figure, which is great! That said, in the reference photo, can you actually see all the muscles you drew? Is the model ripped and flexing? If not, don't try to draw muscles you can't actually see.

Proportion-wise, the figure on the right is better than the one on the left (left looks like the legs are too short). In fact it looks like the figure on the left you went right to the details without first sketching out the overall figure. Overall I would first focus on getting the proportions right before moving on to the details.

you got the forms right, now try and get more into the meat of the drawing. Try to get some shading and detail in.

You are trying to draw the muscle groups under the skin, good observation! The proportioin still need to pay attention at. Try to locate joints like the elbows, knees before draw them all. Find how each part relate to each other and even think of the negative space will help. Nice job, keep working!