Good overview, but begs the question — when you say “messy”, is this a comprehensive review of all the studies written to date on criterion validity? A metareview would be appropriate to pass a final judgement. As a pure field based test (although it maybe not related to lab measures), to compare performance from month to month, season to season … perhaps FTP is useful. Proponents who say that it is a field based alternative to a lab test need to do more reading into all the papers published to date.