There’s a lot of interest from both researchers and athletes in understanding the determinants of athletic performance. In the cycling world, much of the recent focus has been on aerodynamics. As coaches though, our primary focus is on the physiological determinants of performance. The most well-known physiological determinant is VO2max while two other key determinants are lactate threshold and efficiency. These three determinants are interrelated yet also independent, and are important to understand to get the most out of your training.
VO2max stands for “maximal oxygen uptake” and is a measurement of the body’s ability to utilize oxygen during maximal exercise. A person’s VO2max is dependent on their ability to get oxygen into the body, transport it to the muscle, and then the muscle’s ability to use that oxygen. Thus, VO2max provides a glimpse of how well systems like the lungs and circulatory system are functioning. These systems determine maximal aerobic capacity and can be improved with training. It’s important to note though, that genetics play a substantial role in determining VO2max.
Another important physiological determinant is lactate threshold, which we’ve discussed in previous posts. In the research world, lactate threshold is often examined as the percentage of VO2max that a person can continuously maintain during exercise. In general, lactate threshold occurs at ~70% of VO2max but this can be improved with training. The percentage of VO2max that lactate threshold occurs at is largely independent of an individual’s VO2max. As coaches of athletes, what we are typically more concerned about is the VO2 value or the power output at lactate threshold. These VO2 values or powers are more dependent on VO2max. For example, an individual cannot have a lactate threshold of 45 mL O2/kg/min (or let’s say 300W) if their VO2max is 40 mL O2/kg/min (or 275W).
The third (and often ignored) physiological determinant is efficiency (sometimes referred to as economy). Efficiency represents the amount of work the muscle can do with a set amount of oxygen. In cycling, we often examine Watts/L O2. Efficiency is interrelated with VO2max and lactate threshold. There is some evidence that training can improve efficiency although the evidence is equivocal. With regards to performance, efficiency can reflect the number of calories you’ll need to fuel your race or event. This can be a major performance determinant, especially in longer events since you want to avoid the dreaded bonk.
An understanding of these physiological determinants can improve your training. Many athletes focus on improving their threshold while ignoring the relationship lactate threshold has with VO2max. For some athletes, improving VO2max can pave the way for greater gains in lactate threshold. Understanding efficiency and fueling properly during training has also helped some of our athletes make substantial gains in fitness. Thus, focusing on these different determinants can help to make you the most competitive or help you finish your event at your best. Thanks for reading!