VO2 Max, lactate (anaerobic) threshold, and running economy are all considered central to increasing endurance performance. While sports coaches and scientists have their own opinions as to which is most important, most usually give preference to either lactate threshold or running economy; however, there is no strong evidence to support claims that any one alone is key. For the biggest increase in power, speed, and sustained effort, athletes need to work on all three factors.
VO2max is the maximum amount of oxygen that can be used for energy in an endurance activity. The higher an athlete’s VO2max, the greater his or her endurance capability. VO2max is limited as to how much it can be increased; Core Running reports the estimate is somewhere between five to 15 percent depending on fitness status, training history, and training program, although VO2max is unlikely to improve much for those who already have been training for many years. In these cases, it is often better to work on lactate threshold.
For those who can still improve their VO2 Max, quality trumps quantity. Wenger and Bell’s definitive study on VO2 Max and training found that athletes can still increase VO2 Max with as little as three or four solid training efforts per week. The same study further indicated that 35 to 45 minute workouts yielded more improvement than shorter workouts. The key is to train at moderate to high-intensity levels.
The lactate (anaerobic) threshold is reached when lactic acid accumulates in the blood to such an amount as to cause fatigue, muscle discomfort, and a burning sensation. It is generally considered to be the most difficult of the three factors to improve; in fact, the exact methods to effectively increase lactate threshold are often disagreed upon. While some studies show greater improvement when training above the lactate threshold, still others provide evidence of greater improvement training at or even below it.
In the face of such contradictory data, athletes may want to use the principle of training specificity: when trying to increase endurance performance (and thus lactate/anaerobic threshold), athletes may want to err on the side of training at or above lactate threshold.
Running economy refers to how effectively the body can convert oxygen into forward motion. The faster an athlete can run at any given rate of oxygen consumption, the more effective his or her running economy. Pure endurance workouts often do not yield any improvement in running economy; in fact, several studies have shown a decrease in running economy for athletes who train only with steady-pace jogging. There is increasing evidence to suggest that strength training improves running economy.
Athletes trying to increase their endurance performance may want to experiment with longer-period interval training sessions (4 minute runs separated by 2 minute recovery periods) or exhaustive distance training (continuous runs at or near lactate threshold) such as tempo runs. These techniques have shown to improve running economy, lactate threshold, and VO2 max, providing athletes a way of addressing all three critical endurance performance metrics in one workout.