Final answer:
The lactate threshold in untrained people typically occurs at 50-60% of their maximal oxygen uptake. Training can improve the ability to manage lactate production, thus delaying the onset of the lactate threshold and contributing to better exercise performance.
Step-by-step explanation:
In untrained individuals, the lactate threshold typically occurs at around 50-60% of their maximal oxygen uptake (VO2 max). The lactate threshold is the intensity of exercise at which there is an abrupt increase in blood lactate levels.
In more trained individuals, this threshold occurs at a higher percentage of their VO2 max due to adaptations that allow their muscles to manage lactate more efficiently. During exercise, lactate is a by-product of anaerobic glycolysis, and the body usually clears lactate from the blood and recycles it.
However, at high levels of physical exertion, production can exceed clearance, causing an increase in lactate concentration, and leading to muscle fatigue and the associated perception of pain.
Factors that contribute to fatigue during intense exercise include not only increased lactate concentration but also energy availability, oxygen delivery, perception of pain, and other psychological factors.
Therefore, training can improve the effectiveness of anaerobic activity by delaying the onset of the lactate threshold and enhancing the body's ability to manage the by-products of intense exercise.