What is the purpose of a lactic threshold test and how is it used to determine an individual's optimal training intensity?

A lactic threshold test is used to measure the point at which lactic acid starts to accumulate in the muscles during exercise. This helps determine an individual's optimal training intensity by identifying the level of exercise intensity at which they can perform for an extended period without accumulating too much lactic acid. By training at or near this threshold, athletes can improve their endurance and performance.