Horses, Lactate, and the Science of Steady Running

Lactate levels in horses can tell us a lot about their endurance and training needs. Scientists have found ways to predict how much lactate a horse can handle during exercise without getting too tired. This is called the maximal lactate steady state (MLSS). To figure this out, researchers put ten teaching horses through a series of treadmill tests. They wanted to see how well two different methods, called DMAX and DMAXC, could predict the MLSS. The horses ran on a treadmill at different speeds to create a curve showing how their lactate levels changed with speed. The traditional DMAX method looks at the farthest point from the start and end of this curve. The new DMAXC method uses math to find the point that is the farthest from a straight line connecting the start and end of the curve. Both methods aim to estimate the speed at which the horse's lactate levels stay steady. The results showed that the average lactate levels at the MLSS, DMAX, and DMAXC speeds were different. The MLSS speed was the slowest, followed by DMAXC and then DMAX. The differences between these speeds were small, but they were not exactly the same. This means that both DMAX methods can be useful for predicting the MLSS in horses. The study also found that the DMAX methods did not have constant or proportional biases compared to the MLSS. This means that the methods are reliable and can be used to estimate the MLSS accurately. In the end, the researchers concluded that DMAX approaches are good ways to determine the lactate threshold and estimate the MLSS in teaching horses.