VO2 Max: Improve your Aerobic Power

After our previous analysis of the anaerobic threshold (see HERE), today we move onto the cream of the aerobic training crop – VO2 Max. Like our threshold, the term VO2 max can be defined and implemented into a runners program with great effect. By the end of this blog, we hope you have an understanding as to what your VO2 Max is and how you can use it to effectively train towards your next PB!

 What is your VO2 Max?

Your VO2 Max can be defined as the maximum amount of oxygen you can use to fuel your aerobic energy system. To understand this, we need to refer back to how our body uses O2 for energy (aerobic metabolism). For O2 to be used for energy, it is breathed into the lungs and diffused into the bloodstream. Once in the blood, the heart will pump it around the body, where the O2 is taken up by working cells for fuel. Any O2 that is not needed is then returned to the lungs and breathed out. As our exercise intensity increases, the cells in our muscles will demand more and more O2 to keep them working. So our body will begin to breathe in more O2 and continue to pump the blood around the body for use by the cells. If you keep running faster, there will become a point when your body can no longer keep metabolising O2. This is unique for each person and can be due to a lack of efficiency at the respiratory (diffusion of O2 from the lungs to the blood) or the cellular (diffusion of O2 from the blood to the working muscles) level. It’s important to note that it’s not that you don’t have any more O2 available (there will still be O2 in your lungs and blood) but the fact that your body can no longer effectively use this O2 to fuel your aerobic metabolism, resulting in the body breathing out the excess O2 that you can’t effectively use. Once the body reaches a point where you continue to run faster, but are not metabolising any more O2, you have reached your VO2 max – the ceiling of your aerobic system. Where and when this occurs is unique between individuals and is result of your genetics and environment (training) which will be the focus of this blog.

AT

Understanding where our VO2 Max training sits in relation to our other aerobic zones is crucial to maximising the improvements to your running performance

Will Training at my VO2 Max Enhance my Running Performance?

Yes – depending on your goal event. Whilst the AT is the most significant predictor to distance running performance, your efficiency at VO2 max will be of significant importance in events ranging from 2min to ~20 – 25min. If your goal event is likely to take over 30min, improvements in VO2 max will not be of significant benefit to you, without a concurrent improvement in your AT. However, events that are performed above (faster than) your AT, rely on rapid uptake of O2, which is improved with VO2 max training.

 Measuring your VO2 Max

A VO2 max test that measures your O2 uptake with increasing intensity can accurately define the point at which you are no longer able to metabolise O2 for energy. Given the limited access to the equipment required to measure O2 uptake, a more practical solution is the use of a critical velocity (Vcr) or Coopers (CT) field test. If you have recently tested your AT using a Vcr test, you can also use this to accurately estimate your VO2 max. Based upon the best pace you can sustain for 30min (defined as your Vcr), your VO2 Max will fall ~ 15s per km quicker than your Vcr pace.

E.g. If your Vcr Pace = 5min/km, your VO2 Max pace = 4.45min/km

The 12min CT is also an effective way to field test your VO2 max. Simply run for 12min with the aim of covering the maximum possible distance in this time. Once you work out your average pace over the 12min, this equates to your VO2 max training pace.

E.g. If you were able to cover 3000m in 12min, your VO2 Max = 4min/km

Both Vcr and CT methods should net you a similar result, provided your muscular system is conditioned to running that far (12min vs. 30min). If you are coming from a longer distance background (10km or longer) we would recommend the 30min Vcr method, or if you are coming from a shorter distance background (<10km) then a 12min CT can be more appropriate.

 Training at Your VO2 Max

Once you have the pace that correlates with your VO2 max, we can set about training to improve it! As we discussed earlier, your genetics will typically determine the ceiling of your VO2 max (how much O2 you can use to fuel your aerobic metabolism) once you are well trained. However, what we can improve is the efficiency at which your body functions when running at an intensity that correlates with your VO2 max. So if you are new to running and are building up your training load, certainly expect to improve your VO2 max, but for moderate to highly trained runners, expect to see an improvement in the time you can spend training and racing at your VO2 max. To improve your VO2 max, we need to stimulate the aerobic system at its ceiling. As your VO2 max is above your AT, expect an accumulation of H+ and the associated feeling of heavy and fatigued muscles, however we must keep in mind that this is a necessary bi-product of VO2 Max training. Due to the accumulation of the H+, the pace needs to be performed in an interval structure with recovery being very light (either static rest, walking or a very light jog) to allow the body to clear the H+ and continue to perform your VO2 max pace for the next interval.

How long you can spend at your VO2 Max pace is primarily a reflection of your current conditioning to VO2 Max training due to the lower session volumes. Recreational runners should find that in training, they should be able to run for ~10 – 12min worth of intervals at their VO2 Max if they work hard. More seasoned runners should find they can spend up to 12 – 15min at their VO2 Max pace. To enhance your efficiency at VO2 Max we need to gradually increase the amount of time we spend running at your VO2 Max pace. This can be achieved by having either longer reps or more reps at VO2 Max, with greater recovery between the intervals as a compromise. All intervals should be performed at your VO2 max pace, so if you are fading at the end of your reps or cannot sustain the pace at all, there is no point continuing on with that session as you will lose the specific adaptations. Recovery time is typically between 90s and 3min, due to the half-life of H+ ~ 90s. This means that after 90s of static recovery, your body will clear approximately half (~50%) of the acid in the blood and after 3min, approximately another half (~75% total clearance).

Finding a consistent, firm and uninterrupted section of grass is perfect for VO2 Max training

Finding a consistent, firm and uninterrupted section of grass or track is perfect for VO2 Max training

If you can achieve up to 15min of training intervals at your VO2 macx pace, then it would be recommend to re-test either your Vcr or CT to quantify the improvement you have seen in your training. Some example sessions can be seen below:

Recreational Runner

  • 2 sets of 4 x 300m @ VO2 max with 100m jog recovery & 3min rest between sets
  • 8 x 400m @ VO2 max with 60s rest
  • 4 x 800m @ VO2 max with 2min rest 

Serious Recreational Runner

  • 2 sets of 5 x 300m @ VO2 max with 100m jog recovery & 3min rest between sets
  • 10 x 400m @ VO2 max with 60s rest
  • 5 x 800m @ VO2 max with 2min rest

Advanced Runner

  • 2km @ Threshold, 3min recovery, 2 sets of 5 x 300m @ VO2 max with 100m jog recovery & 3min rest between sets
  • 1600m @ threshold, 3min recovery, 10 x 400m @ VO2 max with 60s rest
  • 6 x 800m @ VO2 max with 2min rest

 The 3 principles of progressive overload can be applied to VO2 Max training to improve the aerobic stimulus the session will provide. However, remember that the aim is to spend more time at VO2, so only overload once you are happy with the time you are spending at VO2 max.

  • Firstly, make the run more continuous. E.g. Instead of running 8 x 400m @ VO2 Max with 1min rest, complete 4 x 800m @ VO2 max with 2min rest. Both will stimulate the body for the same volume, but a more consistent application of the training stress will make the run more difficult.
  • Secondly, increase the time period you spend at your VO2 Max. If you can aim to get up to 12min – 15min of interval running at your VO2 Max, you will see a nice improvement in your aerobic power.
  • Lastly, gradually become more active in your recovery (e.g. walking > light jogging). As you accumulate H+ during your intervals, the body needs to clear most of these out of the blood before commencing the next interval, so don’t try to be too active in your recovery and compromise the session

We trust you now have a greater understanding as to what VO2 Max is and how you can use this knowledge to improve your running. If you wish to know more about this topic, or anything to do with your running training, please get in touch with our expert coaching team who are ready to assist you towards your next running goal! Please email or see our website.

 

Running Regards,

Front Runner Coaching Team