Lactate threshold training will help to improve performance times in endurance events such as distance running, cycling and swimming. As its name suggests, this form of conditioning is designed to increase the exercise intensity at which the anaerobic or lactate threshold occurs.
There is some confusion amongst coaches and athletes as to the role of blood lactate and lactic acid in the body. Central to this confusion is how it contributes to fatigue. But regardless of the underlying causes, the accumulation of blood lactate remains a good indicator for subsequent exhaustion (1) and can predict performance in many endurance events (2).
During submaximal exercise, lactate concentration in the plasma remains at a near resting level. As the intensity increases, there comes a point when blood lactate begins to accumulate rapidly in the blood (1). Some researchers contest this suggesting that no specific breakpoint or threshold exists and that lactate accumulation is continuous (3,4,5).
However, from a practical point of view what is most important is that lactate threshold training can delay blood lactate accumulation, in effect shifting the lactate curve to the right. See the graph below:
Although it is difficult to accurately measure lactate threshold outside of a laboratory setting, there are some field tests that may be worth considering in order to determine your own anaerobic threshold. You may even want to consider using a portable lactate monitor and testing kit, which have become much less expensive in recent years.
There is a substantial body of research that shows training at or close to the lactate threshold increases the intensity at which it occurs (6,7,8,9,10,11,12,13). Recall that lactate threshold is often expressed as a percentage of VO2 max. For example, if an athlete reaches VO2 max at a running speed of 24km/h (15mph) and lactate begins to accumulate at 16 km/h (10mph), they are said to have a lactate threshold of 67%.
World-class endurance athletes typically have thresholds of up to 90% VO2 max compared to 50% in untrained individuals (1).
Threshold training (also known as pace, tempo or aerobic/anaerobic training) can be either continuous or intermittent in nature. Both require an exercise intensity at or slightly above the lactate threshold.
One of the most common ways to gauge lactate threshold training intensity is to monitor heart rate. While, a very quick and simple method is to simply assume your lactate threshold will occur at 85-90% of your maximum heart rate, this method lacks accuracy and reliability for many athletes. If you do want to determine training intensity this way, use the Karvonen formula rather than simply deducting your age from 220.
A more reliable method is to determine your heart rate at the lactate threshold and then to train at this heart rate intensity. This is by no means flawless however, especially as heart rate often tends to rise slowly over prolonged exercise periods without increases in intensity a phenomenon known as cardiac drift.
Cyclists can use a power meter to determine the work rate at lactate threshold and thus a suitable intensity for lactate threshold training sessions.
Here is a typical interval lactate threshold training session:
|Interval Training Session|
* LT = Training intensity at Lactate Threshold measured via heart rate or power output etc.
And here is a sample continuous lactate threshold training session:
|Continuous Training Session|