stress fracture

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A fracture of bone caused by repeated application of a heavy load, such as the constant pounding on a surface by runners, gymnasts, and dancers.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A small crack in a bone caused by repeated stress.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun fracture resulting from excessive activity rather than a specific injury