Lactate testing is not a new procedure. It does yield some information that is important for understanding performance. It is still used in sport physiology research but seems to be losing favor for use in applied settings. Australian swimming should heed what is known world-wide. Those understandings and verified uses are far different to what is promoted in Australian swimming.
Lactates are a partial measure of the amount of anaerobic work that is performed in a task.
In sports where localized fatigue is prevalent, it is higher in some parts of the body than in others. When measures are taken in local-fatigue activities such as swimming, those measures are dubious. Lactate measures are affected by many factors. The existence of these modifying factors will decrease the value of the information that is generated by lactate measures. However, a lack of control is also one of the reasons why they are receiving less emphasis in sport settings.