Today we welcome to the pages of Ultra168, Dave Coombs, a stalwart of the Queensland ultra running scene and a pretty tidy runner too. Dave’s a regular on the Glasshouse Trails circuits and puts in some pretty handy performances. So when he asked me if I was keen on an article on VO2 Max Testing and being a little bit of a geek for these types of things, I thought our readers might like a little insight into what it is and how Dave went through his own testing. It makes for some interesting reading. Take it away Dave…
It is the start of a new running season and people are starting to set themselves new goals for 2016. In order to get a clear picture of my own current fitness state and kick start my training I decided, at the tail end of last year, to undertake a VO2 Max Test. This is a service I offer to clients to help guide their training and is something I use myself to make sure I am training effectively. Fortunately, at Physiologic – here on the Gold Coast – we have a fantastic VO2 Max testing facility so I didn’t have far to travel.
VO2 Max is a measure of your maximal rate of oxygen consumption and is usually expressed relative to your bodyweight in ml/kg/min. The people with the highest recorded VO2 Max are generally the most elite endurance athletes with human values topping out around 90ml/kg/min (e.g. runner Kilian Jornet reportedly has a VO2 Max of 92ml/kg/min). Although the general trend is for better athletes to record higher VO2 Max scores, the correlation to race performance is not as close as for other measures such as lactate threshold. What this means is that finding out your own VO2 Max is nice but is not really that useful in itself aside from bragging to your running mates about who has the highest score! So what is the purpose of doing the test if it isn’t to find out your VO2 Max?
The main thing the VO2 Max test does really well is give you a very clear picture of your personal metabolic profile. How well do you burn fat? At what heart rate do you start burning more carbohydrate than fat? Which heart rate zones should you be training in to optimise your training?
My test started in the most relaxing way possible, with a 20 minute resting metabolic test. This measures what your metabolism does when you are not exercising and gives an idea of your fuel usage at rest (more about this later). This is done by wearing a mask connected to an indirect calorimeter which analyses the make-up of your exhaled air. From this analysis, it is possible to work out the percentage of fats and carbohydrates you are burning as fuel.
Next it was over to the treadmill. At first I thought it would be awkward to run wearing a face mask but after a few minutes I got used to it and was able to concentrate on giving 100% during the test. The exercise test is where the real fun begins. Starting at walking pace, Tom, who ran my test, closely monitored what my heart rate registered (via a standard HRM chest strap linked to his laptop) and each time it stabilised he incrementally increased the gradient and the pace of the treadmill until I was running at my absolute limit. The goal of the test is to run (or ride – it is just as easy to do the test on a stationary bike) until you reach RQ=1. This is the point at which you are burning 100% carbohydrate as fuel and basically signals the end of your exercise session – it is impossible to hold this very high intensity for more than a few seconds.
In addition to this my top end carbohydrate burning was quite poor. This is seen in the graph where I almost struggle to get my carbohydrate burning fuel system going even at very high heart rates. This top end is needed for shorter faster efforts, but more importantly for short bursts of strength within a longer event, such as a sudden uphill section in an otherwise flat run, or maintaining leg speed on a taxing technical downhill. This indicated to me that I need to incorporate more strength sessions into my training such as short and fast sprints, or lifting heavy weights.
So what does this mean for my training? Well, I now have some actual numbers to work off for my heart rate zones. For example to train in my aerobic zone, with carbohydrate use kept to a minimum I need to stay under 147bpm when running. Estimating this figure from HR zone formulae would be highly inaccurate.
Many people will be familiar with age-based HR zone estimates such as 220-age=max HR. If I followed this formula I would have a max HR of 220-38= 182bpm. The VO2 Max test showed my actual max HR to be 200bpm. This shows that the estimates can be wildly inaccurate and could lead to poor programming in your training.
The test has also shown where my particular strengths and weaknesses lie and given some clear direction to my training. Armed with this knowledge I can enter into my training for 2016 with confidence that I am training efficiently and not over (or under) stressing my system.
If you would like to learn more about VO2 Max testing or are interested in incorporating HR training into your training please visit these links.