So let's look at what kicked this whole thing off.
The question is:
Is it possible to train VO2max in a virtual race setting?
Let's have a look at some terms and definitions.
Vo2max is defined at the maximal amount oxygen uptake and utilisation that the body is capable of (with a margin of error because - humans). Vo2max is a physiological state, not tied to any other measures ie: you can only really know vo2max by measuring vo2max. This involves being a lab, hooked up a monitor to record gas exchange, HR, power, sometimes core temperature etc.
Maximal Aerobic Power is often used synonymously with vo2max, especially with the standard methods used to determine vo2max (ramp tests etc).. However there are definitions for both, similar does not mean the same, especially when it comes to training. Maximal Aerobic Power is the maximal amount of power that can be produced aerobically. For training purposes this could potentially be expressed as a percentage of Vo2max (depending on testing protocol). More on this below.
Now, there are some issues with vo2max, in terms of the standard measurements, and implications for training. Let's have a look at that:-
This study is deep look at the limitations of vo2max measurements - https://journals.physiology.org/doi/ful ... 01063.2016
This one also looks at the limitations of measurement tests and that in some cases, higher vo2max is recorded *after* the peak power is reached and starts to decline https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3733001/
This study used a different kind of vo2max test, key point :- “therefore, 14 subjects performed two incremental cycling tests: (1) a classical incremental test (CIT) to determine VO(2max), the power at VO(2max) (PVO(2max)) and at the lactate threshold (PLT) (2) a new incremental test (NIT) in which the power was decreased just after the subject reached VO(2max). During both protocols, heart rate, stroke volume, cardiac output, the arterio-venous difference and the oxygen blood saturation were recorded. The results showed that, with the NIT, subject could maintain a long VO(2max) plateau (6 ± 3 min),”
Takeaway - once vo2max was reached, a lower power output continued to work Vo2max at a plateau for a good amount of time.
This looks at the differing ramp protocols. All reached vo2max, but differing peak values. https://link.springer.com/article/10.10 ... 013-2705-9
Close values, but not always the same:-
https://onlinelibrary.wiley.com/doi/abs ... .tb00027.x
The key difference here is vo2max is a simple measurement that is independent of power (or speed etc). It is possible to be putting out relatively lower power than peak power and still be at vo2max, as above.
These points of difference between MAP and Vo2max are relevant for the execution of training.
Lets now focus on Vo2max.
Looking at vo2max we can break it down essentially to two key parts which will determine the given value, basically demand and supply. .
Demand is peripheral - that is to say the working muscles (mostly in the legs for cyclists). Say with me now: the mitochondria are the powerhouse of the cell.
However we must always keep in mind that the rest of the body also needs oxygen. This is important later.
Supply is central, the cardiovascular system. Oxygen is delivered to the working muscles (and keeping the rest of the body alive). Now there are a number of things that can impact how well this system works. Stroke volume, heart rate, plasma volume, lung volume, gas exchange, red blood cell concentration etcetc. You may see Ficks Equation around which is used for the calculation of Vo2:
VO2 = HR x SV x a-vO2diff
HR - Heart Rate
SV - Stroke Volume
A-v02diff - difference of arterial and venous oxygen content.
Study looking at differing measures of Vo2 https://www.atsjournals.org/doi/pdf/10. ... 0or%20both
Charts on here are interesting, and relate to the below. https://pubmed.ncbi.nlm.nih.gov/18006574/
Impacts on training
Training MAP is not necessarily the same as training VO2max. It will definitely work at a high rate of work the “demand” side of vo2, and the supply. However, if we really want improve the supply side of things we need to change variables in the above equation to get more O2 delivered. This could be increasing HR, increasing stroke volume, increasing plasma volume, increasing red blood cell count (EPO anyone?). This is more evidence in more advanced athletes. Getting off the couch, almost anything will improve vo2max.
Now, in other sports, such as running and rowing, operating at ~95% of vo2max may work this aspect just fine. The reason being the increased muscle mass being utilised and the contraction of those muscles results in greater cardiac preload. The preload increases filling in the heart which triggers the Frank-Starling Effect. If you want to read more on this:- https://www.cvphysiology.com/Cardiac%20Function/CF003
For cycling this effect is far less, and this is where the cadence comes in.
These all show that there are generally inefficiencies for cyclists when performing efforts at a higher cadence than usual.
The last study is probably the most relevant:-
“These results demonstrate that pedaling cadence affects the VO2 response profile. The higher cadences speed the primary or fundamental response and hasten the emergence of the slow component. This may have implications for the sport of cycling and should be considered when evaluating cardio-respiratory and metabolic responses to cycle ergometer exercise.”
Normally, we don’t want inefficiencies. However sometimes this causes more work to be done, and in circumstances this is a good thing. Hence, if we use high cadence we not only potentially cause a better preload effect, the process costs more oxygen, hence taxing the central system more (and faster)
Another factor is the “slow component” of vo2max work (just mentioned above). The slow component is basically delay in response in the delivery of oxygen when a given work rate commences. Some reading:-
https://www.researchgate.net/profile/Da ... VO2max.pdf
One quick take away from all of this is that a high initial workload can help the speed of the slow component... as long as you don’t blow up completely and stop.
This study is an important one comparing the slow component between cycling and running. It helps to highlight that you cannot simply adopt training methodologies from one sport to another without CONTEXT.
https://journals.physiology.org/doi/ful ... .85.6.2118
In similar vein, perhaps due to some of the above, maybe a little bit of running goes a long way for cycling….
Can a virtual racing scenario, such as Zwift elicit suitable stimulus for adaptation to vo2max?
Yes, but….. it depends.
Can be highly motivating in a racing setting (higher pain tolerance)
May help with those who are reluctant to do “structured” training
Lack of negative environmental factors (rain, wind, etc)
Potentially better access to hydration and fuel for longer sessions and repeated bouts (highly important for high range efforts).
May not be optimal depending on the nature of the racing and virtual topography
Potential lack of repeatable and consistent efforts - again, due to the above
Negative effects of indoor training - namely heat stress
Inconsistencies of some smart trainers (if only source of power data).
Analysis of TPs race file:
In addition to my earlier quick take, with the above information, hopefully we can all see a circumstance that definitely work vo2max. High initial load, a decay in power but still at a sufficient level to drive a longer vo2max exposure. Had the high initial load resulted in complete exhaustion then the work done at vo2max would have been far too little. In this case it was kept pretty damn high.
I mentioned above the oxygen demands of the body. “Going anaerobic” is not always a negative, as long as you don’t stop, the oxygen demands of the continuing working muscle, the anaerobic glycolytic replenishment and all other demands means that the circumstances by which vo2max will be experienced is very possible.
The only other piece of the puzzle would have been the cadence for the effort. If sufficiently high, then this would have helped the cardiac preload.
I am sure i have skimmed over pieces and left out crucial bits...but hopefully this all makes sense.
Note: This does not invalidate other short duration steady state efforts - they 100% still have their place.
Note: Your mileage may vary.