Australian mountain biking history and urban legend is thick with stories of stars with great VO2max ratings. Back on day two World Cup cross country winner Cadel Evans blew the doors off the AIS (device used to measure VO2max) cart with his hot air balloon sized lungs.
Amazingly, strangely (and sadly it won't happen again unless it's an Olympic sport) the Reversers were even invited to the AIS to test their physical condition. Sports legends Mick Ronning and Scott Sharples shocked many at the test site with their incredible VO2max numbers. Rumors circulated in the national Suntour MTB series that “they weren't far off the XC riders VO2 numbers”. This article contacted then coach Damien Grundy about the actual VO2max ratings of the riders but Damien remained tight-lipped and Cadel, Mick and Scott's numbers remain a mystery.
What is VO2max?
More than a century ago the pioneering scientists Hill & Lupton conducted seminal studies that still influence sports science today. Hill studied runners who ran in his backyard and noticed that the faster they ran the more oxygen they needed until there was space on the plateau for oxygen, not because the runner “didn't need oxygen” but “because he couldn't get it”.
They could continue to run or increase their running power but the actual oxygen consumption rates were not increasing—they were plateauing—and it is this plateau that defines the magnitude of VO2. Currently, mainly in laboratory tests the emergence of the Vo2 plateau has been checked against Heart Rate plateaus, lactate levels above 8mmol mmol·L−1 and Perceived Performance Level above 17 out of 20 to determine the VO2max Plateau happened (Milet). and others, 2023).
VO2max is defined in two ways: absolute and relative. Absolute VO2max is a measure of the total amount of oxygen (O2) can enter the body in one minute (L/min), which is related to the amount you can get compared to your body weight per minute (mL/kg/min).
Taller, more muscular riders tend to have higher VO2max, think Sam Gaze, Greg Minnar, Anika Langvad. Taller and smaller muscular riders – Tom Pidcock, Jackson Goldstone, Mra Mitterwallner may have a lower overall VO2max but when measured against body weight the VO2max per kilogram may be greater. This equates to big, powerful riders having an advantage on flat or rolling terrain, while smaller riders dominate on steady climbs.
Can VO2max be trained?
A little bit. This is where the old trope of choosing your parents well comes into play. Continuous training over the years improves the heart's left ventricle size and stoke volume so with every heart pump more blood and this O.2 it is transported to the muscles. Training also increases the number and mitochondria and the density of the capillaries in the muscle which increases the absorption of O.2 from the blood to the muscles which can be used to create ATP to power the body. All this adds up to the consensus that VO2 can be improved by about 5–15% (Couzens, year unknown). The limit to VO2max training adaptation is the size of your lungs and thoracic cavity to which they can grow, both of which you inherited from your elders, especially your Mother!
Does VO2max predict MTB performance?
Well then. It depends on the discipline of MTB and also runs into a big debate about VO2 as a predictor of athletic performance in sports. It seems that good performance in sports, especially endurance sports VO2 only makes up one part of the three part body composition equation (the mental aspect plays a role in performance as well but this article will focus more on body composition).
The three main pillars of sports performance seem to be VO2max (low training), maximum lactate threshold (high training) and really good performance (high training) wherever you intend to go (Joyner, MJ, & Coyle, EF 2008).
Although it has been shown that a greater VO2max can be useful in predicting athletic performance it is not the whole picture. Cyclist with the highest measured VO2 – Oskar Svendson from Norway with a speed of 96.7 ml/kg/min! Cadel reference is rumored to be in the mid to high 80s.
You can imagine that Svendson will be handling bikes for many years to come. With a good start winning the 2012 time trial in the road world, he did not succeed as a U23 rider and quit the sport two years later. Svendson's departure many believed was due to his lack of efficiency; because he had such a high VO2max he burned many matches attacking and using his strength all the time.
Still, it's a good example of VO2max being a predictor of cycling success but not the only factor. Among the athletes I train for XCO those with very high VO2max ratings do not achieve the best performance compared to athletes with low VO2max ratings and good tracking skills (efficiency) who achieve better performance.
The Gravity athletes I train seem to get fitter the better they play and the more they train their results seem to improve, but this is a myth for now: I need to get them into the lab and start testing their VO2max. comparing it to race results for a more scientific take on this.
Overall it seems that being good at all three rocks – (VO2max, high lactate threshold, efficiency) creates the best chance of performance while being elite in one but lacking in the other seems to lead to less performance.
What role does VO2max play in Mountain Biking, a summary
If we look at the chart above we can see the body has a number of energy systems, some are extremely powerful and create a lot of energy (y-axis) but for a very short time (x-axis) e.g. the muscles of the human body to power from motionless to very fast in a few seconds think at the start of a pump track race. Some energy systems burn less energy for a long time: the Glycogen system can build energy for a few minutes and this can be the best energy system in a downhill race.
And then the small power (iy-axis) but theoretically lasts forever the aerobic system (VO2max) – think and XCO or XCM event; these use the glycolytic system for short bursts of energy, but the hardest working system is their aerobic energy system.
A common misunderstanding is that the body uses one energy system separately: this is never the case. It always uses a mixture of aerobic, lactic (mainly to give energy to the heart and mind) and glycolytic so that the body can meet the demands of the running event.
The role of VO2max in XCO/XCM Mountain Bike racing?
To meet the energy needs of the long distance, duration XCO (90mins) and XCM (3hrs+) A rider with a high VO2max uses a large combination of endogenous aerobic energy sources supplemented with small amounts of glycogen. A rider with a low VO2max on the same stage is able to access smaller amounts of aerobic energy supply and is forced to use larger amounts of limited glycogen to cover the same course. Glycogen quickly depletes leaving the rider unable to perform vigorous efforts (hills!) quickly.
They can still ride but it will be at a lower intensity and they will struggle if higher intensity (more hills!) is demanded of their bodies, this is what XC riders call bonking, or being cooked. Of course, once the glycogen has been used it can be replenished with the right food, but the benefit of having a high VO2max at this stage of the race can be seen in the way it saves glycogen for energy efforts in the long term.
The role of VO2max in DH and enduro Mountain Bike racing?
The chart above shows that in the first 2 minutes the dominant energy system used to meet the energy demands of a DH/Gravity race is ATP-PC, glycogen and lactate. Most DH and enduro races are 3mins+ so it's important that DH riders and enduro riders have a strong aerobic/VO2 system so when the race goes through the first 2mins of glycolytic energy they have plenty of energy supply are found in the aerobic system. Think back to Ronning and Sharples, both mixed DH and XC racing so they had a very large VO2max, hence no problem with getting into an aerobic program during the last brutal minutes of a DH race and probably one of the reasons they were so good .
On top of the demands of a DH/Gravity race are pre-race energy demands including– track walking, high repetitions in track training and fitness runs all repeat the process of exhausting the high energy systems and relying on the aerobic/VO2 system. Being aerobically fitter/higher VO2 aids in recovery among all these things! The role of maximum VO2max is underestimated in DH and Gravity racing.
How should you VO2 train for XC and Gravity racing?
That will be in the next issue, stay tuned!
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