First of all thanks for your kind words about the book and website.
You chose your parents well! Someone with just 3 years of training under their belt and a maxVO2 of 72ml/kg/min has probably got a genetic predisposition for endurance. I’ll address your points below but with a brief summary first.
A person’s oxygen uptake (rate they use oxygen in their muscles during exercise) is an indirect measure of human power. It does not correlate particularly well with endurance performance. It is not a measure of endurance per say (as is often misinterpreted). It IS a measure of endurance POTENTIAL. When it comes to predicting or measuring actual endurance the best biometric indictor if the speed at ones lactate threshold (also called anaerobic threshold). However top endurance athletes often have very high maxVO2. People make the old correlation is not causation mistake.
Lactate Threshold and maxVO2
Well trained endurance athletes can achieve LT HRs as high as ~90% of their maxVO2. 90% of 72ml/kg/min (like yours) is going to be higher than 90% of 62ml/kg/min. MaxVO2 puts an upper limit on endurance. Improve maxVO2 and you can potentially improve endurance by raising the LT. But keep in mind that it is performance in the filed that athletes are concerned with: Your running speed, your uphill skinning speed or the speed you can front point up the 3rd ice field on the N Face of the Eiger. These are real performance metrics. Just increasing the LT HR or VO2 at LT doesn’t necessarily translate to performance becasue of little thing called economy. An athlete with high economy uses less oxygen to for the same speed than one with low economy. This explains why races are held: If all the mattered was a laboratory measurement of maxVO2 or LT, athletes would only need to present their lab test results and the medals could be handed out based on those. We often see athletes with low maxVO2 beating those with very high numbers due to better economy.
Relative vs Absolute maxVO2
Relative is also sometimes called “Specific”. Absolute is a gross measure like the horsepower of the engine in your car. 200 horsepower in a car or 6L/min of O2 uptake in a human. But a 200 horsepower engine in a heavy car will not yield as much performance as a 200 horsepower engine in a light car. So we divide the absolute O2 uptake by the athlete’s body mass in Kg to get a measure of horsepower per kg. This allows us to compare from athlete to athlete regardless of the size of the person. Relative maxVO2 is important in endurance sports where athletes have to overcome the effects of gravity in their locomotion (running uphill). In a sport like Rowing where the athlete mainly has to overcome the resistance of the water on the boat’s hull with our lifting his body mass relative to the earth (gravity) the absolute maxVO2 is very important and is why you see a natural selection of bigger athletes in rowing than in running. As to your question regarding the 70 vs 60kg athlete having more upside in LT. I can’t see any reason why that would be so.
First Wave Response
This means that the adaptations that result in increased maxVO2 occur quite rapidly when engaging in endurance training. Especially in the young and untrained. Genetics seems to play a big role in response rates and ultimate values. Notice that the numbers you present for Kilian were recorded when he was young. The young (adolescents through mid twenties) are the most trainable in most athletic qualities.
If you stay on the treadmill 2-3 minutes longer using the same test protocol this will mean that you will be moving faster and will most like see an increase in maxVO2. But an increase in speed can come from improved economy and a higher LT as well.
I hope this helps