I answered a similar question a couple days ago in a META thread, actually. The answer is that medieval fighting men did have bone markers that we can use to identify some of their likely occupations, and that may have caused stress over time.

The exact thing I was answering was regarding longbowmen, who could be identified among remains found on the English ship Mary Rose which sank in the Solent in 1545 and was raised in 1982. Cheryl A. Fury edited a book about the archaeology of the ship, which includes a section about the skeletal remains found and how the scientists distinguished between longbowmen, who have repetitive-stress markers related to a condition called os acromiale, and sailors who had other injuries that showed up in skeletons (mostly fused spines and broken bones). Here is the book on Google Books, with references to the condition highlighted.

You may also be interested in this post from /u/evanrwt in that same thread, which mentions archaeological work done at the site of the battle of Towton; there, researchers were able to distinguish between skeletons of bowmen vs. men using other weapons based upon bone markers. A good reference for more on Towton is Fiorato et al., Blood Red Roses: The Archaeology of a Mass Grave from the Battle of Towton AD 1461 (Oxbow, 2007), which is also available on Google Books.