Inside The Lab: How A VO2max Test Could Help You Take That Next Leap
The purpose of assessing an individual’s VO2max (maximal rate of oxygen consumption) throughout exercise (walking, cycling, swimming), is to objectify cardiopulmonary and metabolic function – the current gold standard. It is widely understood that an individual’s VO2max is strongly correlated with chronic disease risk, longevity, wellness and lifespan. But what does it have to do with endurance performance?
Both individual and team sport participants can reap the rewards of better understanding their physiology, through directly tackling their weaknesses through targeted and specific training interventions. Who doesn’t want to run faster, recover quicker and remain injury free?
After a couple of years of referring my own athletes for VO2max assessments (Melbourne Sports and Allied Health Clinic; msahc.com.au), I decided to put myself to the test and find out the intrinsics of my own running physiology, and where to direct my training to further improve my weaknesses.
The test:
The treadmill running assessment begins at my comfortable jogging speed (13 km/h) and increases by 1 km/h every 3-minutes (the time it takes to reach a ventilatory steady state) until I reach my anaerobic threshold/VT2 (determined through measuring my blood lactate via finger prick/capillary, and via carbon dioxide shifts in relation to oxygen consumption). When I finally reached VT2 (18 km/h; 17:30min) the pace remains, and the incline is adjusted by +2% every 1 minute until I reach my VO2max (respiratory exchange ratio exceeds >1.10 and a plateau occurs in VO2). Additionally, my heart rate and rate of perceived exertion (how I feel/effort at x pace/intensity) is assessed. At the conclusion of the test (22min), I was running at 18 km/h +8%, with 193bpm HRmax, 16 mmol/L blood lactate and 77.0 ml/kg/min VO2max.
The raw data:
Training zones
Z1: 130-145 bpm
Z2: 145-160 bpm
Z3: 160-168 bpm
Z4: 168-175 bpm
Z5A: 175-180 bpm
Z5B: >192 bpm
Glossary of Training Zones/ RPE
Z1 (recovery; light aerobic) 10-11
Z2 (moderate aerobic) 12
Z3 (tempo) 13-14
Z4 (subthreshold) 14-15
Z5A (anaerobic threshold) 15-16
Z5B (VO2max) 19+
What does all this data mean?
My aerobic threshold (VT1), aka top end of zone 2, is equivalent to 71% of my VO2max, 160bpm, at approximately 3:50/km. What I found super interesting was that my zone 2 was quite broad, ranging from <13 km/h to 16 km/h. These are the paces I will be training within for my recovery to moderately paced aerobic runs, Z2 equating to 145-160bpm, 12 RPE.
Anaerobic threshold (VT2) – commonly known as the pace your coach/training partners are always attempting to guess in training! This metric is essentially the final stage prior to tapping into a greater proportion of anerobic energy/fuel, with increased lactate and CO2 production being a prime indicator of this metabolic shift – a shift from mixed fuel (fat + carbohydrate) to exclusively carbohydrate oxidation. My LT2 was identified at 83% of VO2max, 175bpm at 18km/h (3:19/km). My threshold training will be completed at Z4-Z5A, 168-180bpm, 14-16 RPE. Anaerobic threshold that is closer to VO2max is a huge contributor to endurance performance!
The training implications:
The data collected can be quite overwhelming without context and references. My VO2max places me in the 99th percentile for my age (24-25years), which means I have a diesel engine behind me, and very healthy! But why am I not performing with the best in an Australian 5-km final?
Middle-to-long distance performances are not solely determined on the person with the largest VO2max, rather, a combination of VO2max (engine), lactic threshold (max velocity/speed in aerobic zones/top speed in a low gear) and metabolic economy (efficiency/miles to the tank). If I were to place emphasis on any of the aforementioned three variables to influence middle-to-long distance running performance, it would be your metabolic economy!
My metabolic economy measured from a sub-maximal work rate below anerobic threshold, and in my case at end-Z2 was 202.5ml/kg/km, however the ideal target of <185 ml/kg/km means that this is essential for improving my running performance. For my strong engine to perform like an F1, I need to become greener and improve my fuel efficiency.
How is this possible?
The best way to improve metabolic economy is to increase my running mileage, sub-threshold running and maximise my strength training! Having consistently ticked the strength training box with tri-weekly targeted strength, that leaves a much simpler task for my coach and I to target in training. Strategic nutritional modifications are another important factor, with a focus on how my body can use fatty acids more effectively in training and competition.
Final thoughts:
Being a full-time Exercise physiologist and running coach, I invest a fair chunk of my limited spare time toward my own training – which most of you reading may find relatable. Leaving the guesswork out of training with my coach will not only allow me to now capitalise on improving my weaknesses, but also optimise the little time I have remaining in my week toward optimal and specific training.
If you have any questions, please feel free to reach out to me directly!
