I will try answering this question as it will help me gain a better understanding of the concept. Be sure to correct me where I am wrong as I did not do units 1/2 last year and find it as a little tricky concept to get around.
Apparently, LIP wasn't done very well last year, and so, like always, VCAA tests topics that were not done well in the previous year. It is very likely that they will have LIP this year, if not all the past exam papers.
From my understanding, Lactate Inflection Point (LIP) is where lactic acid starts to accumulate in the blood stream. This occurs because lactic acid is produced faster than it can be metabolised/removed.
Intensities beyond the LIP = fatigue. The higher the exercise intensity above the LIP, the more rapid the fatigue is. This is because there is a greater reliance on the anaerobic metabolism to supply ATP, which results in accumulating by-products.
[IMG]http://img133.imageshack.us/img133/5236/fdsfme0.th.jpg[/img][IMG]http://img133.imageshack.us/images/thpix.gif[/img]This graphs shows where LIP occurs. Be sure to know how to look at a graph and pinpoint where it unfolds.