An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Cook JL, Khan KM, Harcourt PR, Grant M, Young DA, Bonar SF.Cook JL, et al. Among authors: khan km.Br J Sports Med. 1997 Dec;31(4):332-6. doi: 10.1136/bjsm.31.4.332.Br J Sports Med. 1997.PMID: 9429013Free PMC article.