Blood lactate markers are used as summary measures of the underlying model of lactate production in athletes. Several markers have appeared in the literature in the last 20 years and papers comparing their performance (i.e. relation to endurance) presented.

A typical lactate curve exhibits a curvilinear pattern but there is no consensus on the true model of lactate production. The main debate concerns whether a lactate curve is comprised of two sections -- linear baseline and a region of rapidly increase lactate production. The intersection of these two sections is thought to represent a breakpoint, or threshold [1,2,3,4,5]. The alternative suggestion is that a lactate curve is simply a smooth monotonicly increasing curve [6]. Given this debate several markers have been suggested. Typically each marker corresponds to a workload in the region of high curvature in the lactate curve.

To date no free software exists that allows the sports scientist to calculate these markers in a consistent manner. In this paper software is introduced for precisely this purpose. The software will calculate a variety of lactate markers for an individual player, a player across different time points (e.g. across a season) and simultaneously for a team.

A concise description of the markers considered is given in addition to the algorithms used to calculate the markers. Keywords: Lactate Curves, Endurance Markers, Software.