Interval Training: One way…

vVO2Max Training

There have been scientific studies which concluded there is a pace for running (cycling, or exercising in general) which increases leg muscle strength and power, and that pace is pretty close to vVO2Max. Running at this pace during training tends to improve economy through strengthening muscle cells (meaning fewer cells are needed to run at a particular pace), and boosting neuromuscular responsiveness and coordination.

What is vVO2Max?

vVO2Max is a scary looking term, but it’s just a convenient way of writing the speed at which an athlete runs (or cycles) for maximal oxygen uptake. Let’s look at the components of the term:

v
Stands for “velocity” or speed.
VO2
Refers to the volume (V) of oxygen (O2) your body is capable of utilising in one minute. Oxygen is consumed by the body in the conversion of the stored energy from the food you eat into the energy molecules, called adenosine triphosphate (ATP) which are used at the cellular level during exercise. VO2 is expressed either as an absolute rate in (for example) litres of oxygen per minute (L/min) or more commonly as a relative rate in (for example) millilitres of oxygen per kilogram of body mass per minute (e.g., mL/(kg·min)).

VO2Max
The maximum rate of oxygen consumption.

So, we’re interested in finding vVO2Max, the minimal running velocity (slowest speed) which “causes” VO2Max i.e. causes your muscular system to utilise oxygen at its highest possible rate.

In addition to knowing the slowest speed which causes VO2Max, we also need to know how long we can sustain that pace i.e. the limiting time, or tlimvVO2Max. Fortunately for us, a professor of Sport Sciences at the University of Lille was able to show that tlimvVO2Max, on average, was 6 minutes1, so we can use this limiting time when determining an estimate of our vVO2Max.

How to estimate your vVO2Max?

You can go to a sports laboratory and have this professionally measured and get a very accurate result, for a cost. The cheaper way is to get a close-enough result by doing some testing ourselves, by performing our own “stress test”.

This is a stress test, with very strong emphasis on stress!

Anyone who has undergone a stress test will know that it is not easy. A stress test although relatively short does require you to push your body and your heart to the very limit. Before undertaking a stress test, you should be certain of the following:

  • You have not got a cold, flu, stomach bug or other illness. If in any doubt check with your doctor.
  • You have not fully recovered from a previous race, training session or another stress test.
  • Do not undertake a stress test with any hint of an injury. Ensure all old injuries are fully repaired before deciding to undertake stress test.
  • Anyone who is overweight or over the age of 35 is advised to see their doctor before undergoing a stress test.

I hope that you get the idea that a stress test is not easy. It is the very limit of your heart and body’s capability and should not be treated lightly.

Conduct of testing

  1. It is important to warm up thoroughly.
  2. The test: Run as fast as possible, as consistently as possible, for six minutes. This can be achieved on a treadmill (preferred option, as it prevents the runner from (subconsciously) slowing down) but is still achievable outdoors. Running on a flat track is preferred to cross-country or trails.
  3. Record the distance covered (in metres) during the effort.
  4. Compute vVO2Max by dividing the distance covered (in metres) by the time taken (in seconds) i.e. dividing the distance (in metres) by 360 (seconds). The units of the resultant vVO2Max will be metres per second (m·s-1).
  5. After a recovery period (suggest 10-15 minutes) run the test again and determine a second vVO2Max value.
  6. Use the faster velocity as vVO2Max.
  7. Cool down and stretch.

The purpose of running the second interval is to determine whether the maximum effort was performed in the first interval. Athletes sometimes will subconsciously hold some effort in reserve, or some athletes won’t have a proper mental appreciation of the duration of the test; some may run too slow for the entire test, or run too fast at the start of the test and fade at the end. A second effort will often resolve this, but may not be required with more experienced athletes.

If the athlete is wearing a Heart Rate Monitor (HRM) at some point in the second effort, they should achieve a heart rate which closely approximates their Maximum Heart Rate (HRMax) and it would be prudent to record this value.

Training regime

For three weeks following the vVO2Max test, in addition to their tempo and endurance training, athletes should conduct one session of the following, preferably in the order listed.

To provide an example, let’s say a runner covered 1800m in the 6 minutes of the stress test. Their vVO2Max is 1800÷360 = 5m·s-1. (This is a LOT faster than I run, but the numbers are nice to use for this example.) Their training would look like:

30/30 intervals

  • 30 seconds at 100% of vVO2Max
  • 30 seconds recover at 50% of vVO2Max

This cycle is repeated for as long as the 30 seconds at 100% vVO2Max can be sustained. I like to use a “three-strike” policy when it comes to achieving each effort: If the athlete fails to run the required distance in the required time, once, it might be because of a factor beyond their control or they lost concentration, or whatever; strike one. If they fail to meet the distance in the required time for a second instance, it probably means they are beginning to fatigue but they have to dig deep and keep trying; strike two. After the third instance of failing to meet the distance and time target, it’s time to end the session; strike three, you’re out. The strikes don’t have to be consecutive.

e.g. Based on achieving 1800m in the 6 minute stress test (5m·s-1) then in 30 seconds they can cover 5×30 = 150m. This training session would comprise of 150m run in 30 seconds followed by 75m jogged in 30 seconds. This is repeated until they are unable to maintain the 150m run in 30 seconds.

The 30 seconds at 100% vVO2Max is important, as this is the element from which the gains in fitness will be achieved. The recoveries need to be run slowly and reasonably close to 50% vVO2Max.

60/60 intervals

  • 60 seconds at 100% of vVO2Max
  • 60 seconds recover at 50% of vVO2Max

This cycle is repeated for as long as the 60 seconds at 100% vVO2Max can be sustained (three-strikes).

e.g. Based on achieving 1800m in the 6 minute stress test (5m·s-1) then in 60 seconds they can cover 5×60 = 300m. The session would comprise of 300m run in 60 seconds followed by 150m jogged in 60 seconds. This is repeated until they are unable to maintain the 300m run in 60 seconds.

3/3 intervals

  • 3 minutes at 100% of vVO2Max
  • 3 minutes recovery

This cycle is repeated for as long as the 3 minutes at 100% vVO2Max can be sustained or 5 repetitions have been completed.

e.g. Based on achieving 1800m in the 6 minute stress test (5m·s-1) then in 3 minutes (180 seconds) they can cover 5×180 = 900m. This session would comprise of 900m run in 3 minutes followed by 3 minutes recovery, jog or walk (the distance is not important). This is repeated until they are unable to maintain the 900m in 3minutes or 5 repetitions have been completed (whichever happens first).

Post-intervals

After each intervals session, cool down properly by going for a slow jog, slowing to fast walk and then finally a period of walking at slightly quicker than normal pedestrian pace. Stretch as required.

Generally, keep moving for as long as possible following the session; don’t flop onto the couch!

Re-evaluation

The week after the third vVO2Max session, conduct the vVO2Max stress test again to determine a new vVO2Max and quantify any performance improvement.

If the athlete is not suffering from fatigue or injury, their vVO2Max should have improved as their VO2Max, running efficiency and onset of blood lactate accumulation (OBLA) should have also improved. For subsequent training sessions, use the faster vVO2Max value, even if that value was determined from a previous stress test.

Comments

One of the many things I like about this method is that anyone can use it. What I don’t like about a lot of the interval plans you see on the net or in books is that most of them are distance based and not everyone can run, for example, 3 one mile (1600m) intervals. Some people have to dig deep and struggle to run (walk) 3 miles (5km) at a steady pace, especially at the start of their training, so, a lot of people wont do an interval session during their training and therefore wont receive the benefits they can provide. Timed intervals i.e. putting in an effort for a period of time rather than for a specific distance can be more easily implemented by more people; runners or walkers.

Another thing I like about this method is that the interval sessions don’t have a finish per se; you do as many repetitions as you can (don’t overdo the 3/3 though, stop after 5 reps). This means that if you’re genuine about your effort, there is no way you cannot achieve your goal because there isn’t one! If you were supposed to run, say, 10 intervals in a session but could only manage 8 then you might think you’ve failed, even though a genuine 8 efforts is still a worthy achievement. Using the “three-strike” method to determine the end of the session even gives a little bit of latitude, but it encourages the runner to put in little more effort when they think they want to quit. If there is no magic number of repetitions to be achieved, there is no way to fail; I like this positivity during training.

If you’re still in the building phase to your fitness, this will be apparent in the stress testing, now when compared to the improvement which will become evident in the following months. With this intervals method, you get a “progress score” each month… the sooner you start, the sooner you get to see progress.


Disclaimer

I’m NOT a qualified coach or sports physician or expert. Use this information for education and entertainment purposes only.


References:

1. BILLAT, V. (1999) Interval training at VO2 max: Effects on Aerobic Performance and overtraining markers. Medicine and Science in Sports and Exercise, 31 (1), pp. 156-163

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