Through endurance training, how much might you be able to improve your maximal oxygen consumption?

What is VO2 Max? Charts, Tests and Training

VO2 max (or maximal oxygen uptake) refers to the maximum volume of oxygen used during intense exercise. It’s considered to be the gold standard measure of cardiovascular fitness and has been shown to be important for success in a range of endurance sports.

Not only is VO2 max important for endurance sports, it’s also an important indicator of overall health and fitness.

WHAT IS VO2 MAX?

VO2 max gives a measure of cardiovascular fitness, but what does it actually mean?

VO2max is a measure of the efficiency of your whole aerobic system. It provides a quantifiable way to assess cardiovascular fitness by measuring the maximum amount of oxygen consumed during intense exercise. This is expressed as millilitres of oxygen consumed per kilogram of body weight per minute of exercise (ml/kg/min).

As such, it provides insights into the combined efficiency of your respiratory, cardiovascular and muscular systems.

In this way, your VO2 max is dependent upon:

1. The efficiency of your respiratory system (lungs) to inhale and absorb oxygen.
2. The ability of your cardio vascular system (heart, blood, blood vessels – arteries, veins, capillaries) to efficiently pump, transport and distribute oxygen around the body.
3. Your muscles ability to consume large amounts of oxygen – this is dependent on factors like the proportion of slow twitch muscle fibres, the amount of mitochondria, aerobic enzymes and muscle capillary density (very small blood vessels that deliver oxygen to individual muscle fibres).

Absolute vs Relative VO2max

Whilst VO2 max is most commonly expressed in relation to bodyweight it is sometimes expressed as an absolute value:

• Absolute VO2 max – the total volume of oxygen consumed per minute e.g. 4 Litres per minute (or 4.0L/min)
• Relative VO2 max – the volume of oxygen consumed per kilogram of bodyweight e.g. 60ml per kg per minute (60ml/kg/min)

Both are useful, however, relative VO2max is considered more beneficial since it takes account of bodyweight.

What’s a normal VO2 max Value

VO2max values can vary greatly between individuals with untrained individuals typically recording a VO2 max in the range of 25-45ml/kg/min. However, some people naturally have a much higher aerobic capacity, even when untrained.

So, what is considered a good VO2 max?

The table below provides information on what’s considered a good VO2 max. However, as you will see later in this article, elite athletes can achieve more than double these values.

WHY IS VO2 MAX IMPORTANT?

So, why is a high VO2 max important?

The higher your VO2 max, the greater your ability to use oxygen during exercise i.e. greater cardiovascular fitness. As such, it’s an important predictor of success in many endurance sports like running, cycling, triathlon, duathlon, rowing and cross country skiing. It’s also a useful predictor of overall health.

While, there are numerous benefits to improving your aerobic fitness, the greatest benefit comes from an improved ability to consume and use oxygen.

In this way, an improved VO2max indicates an improved ability to:

• Uptake oxygen (greater lung function)
• Circulate oxygen (improved heart and cardiovascular system)
• Consume oxygen (stronger and more efficient muscular system)

This is important for two main reasons:

1. Improved health
2. Athletic/sports performance

Health Benefits

Firstly, improving aerobic fitness is extremely important from a health perspective. In fact, there are numerous research articles demonstrating the link between aerobic fitness and:

• Improved quality of life and longer lifespan
• Reduced risk of disease (heart disease, strokes, cancer and diabetes)
• Improved mental health (reduced risk of depression, better sleep quality)

It’s also an important predictor of exercise performance.

Endurance Sport

VO2 max is considered an important predictor of success in endurance sport. So, why is that?

An athlete with a higher VO2 max has a greater ability to uptake, transport and use oxygen during exercise.

In this way an athlete with a high VO2max will have:

• A very efficient respiratory and cardiovascular system that can uptake and transport large amounts of oxygen around their body.
• They will have muscle fibres that can efficiently absorb and use oxygen from the blood.
• And, the conditioning to work at high intensities ‘aerobically’ for sustained periods of time.

Taken together, this means they have the potential to work at higher intensities, or work rates, before the demand for oxygen exceeds the supply.

An important predictor of success in endurance sport

Not surprisingly VO2max is considered to be a key determinant of endurance exercise performance (Conley and Krahenbuhl, 1980; Morgan et al., 1989; Jacobs et al., 2011).

Interestingly, a high VO2 max may be even more important for older athletes, where research suggests that it may be a better predictor of endurance performance capacity than the lactate threshold (Marcell et al., 2003; Wiswell et al., 2000).

Whilst, it’s importance has been questioned by some researchers and coaches; the majority of elite endurance athletes record very high VO2max values (Noakes, 1991; Daniels and Daniels, 1992). And it’s uncommon to reach elite level in endurance sport, without a high aerobic capacity.

Having said that, it’s important to remember that VO2 max is one of many factors that contribute to endurance exercise performance: exercise efficiency, Lactate threshold and vVO2max or the power at VO2max.

As such an athlete with a higher VO2 max will not necessarily out perform an athlete with a lower VO2max. And while, a high VO2 max gives an athlete the potential to reach an elite level, their performance is also be dependent on other factors (Conley and Krahenbuhl, 1980; Morgan et al., 1989; Fallowfield and Wilkinson, 1999).

As well as improving endurance exercise performance, there’s another key benefit of having a high VO2max…

Improved recovery from exercise

One often overlooked benefit of having a high VO2 max is improved recovery from exercise.

So why is aerobic capacity important for improve recovery from exercise? This is likely linked to an improved capacity to transport blood, oxygen and key nutrients around the body.

In this way, a high VO2 max can allow athletes to:

• Complete larger training volumes
• Recover more quickly during training sessions – require shorter recovery periods between intervals
• Recover more quickly after training sessions

Why is improved recovery important for success in endurance sport? 

• Simply put, an improved recovery is important due to the physiological demands of the large training volumes and intensities utilised during endurance training.
• In this way athletes with a higher VO2 max may be able to train harder, or at higher intensities, and cope with larger training volumes.
• Being able to cope with and adapt to these volumes and intensities is key to long term success in any endurance sport.

This supported by research, looking at the effects of interval training on excess post-exercise consumption (EPOC). In this study, researchers found that those with greater cardiovascular fitness (i.e. higher VO2 max) had a reduced magnitude of EPOC (Matsuo et al., 2012). In other words, they had a quicker return to resting metabolism than those with lower VO2 max.

VO2 MAX CHART ELITE ATHLETES

Elite endurance athletes record much higher VO2max values than those recorded for untrained or trained individuals. Typically elite endurance athletes may have a VO2 max in the region of 60-85ml/kg/min – 60-75ml/kg/min in women and 70-85ml/kg/min in men – with some athletes recording values of greater than 90ml/kg/min.

VO2 MAX Chart Elite Men

The following chart shows examples of some of the highest recorded VO2 max scores for elite men.

VO2 MAX Chart Elite Women

The chart below shows some of the highest recorded VO2 max scores for elite women.

FACTORS AFFECTING VO2 MAX

There are a number of factors that affect an individuals VO2max, including:

• Age,
• Gender,
• Genetics/physiology,
• Altitude,
• Bodytype/bodycomposition,
• Training status,
• Exercise type

Age

Not surprisingly, age is strongly linked to VO2 max, with the highest values typically recorded between the ages of 20-25.

Why is that?….well, as we age our VO2 max is known to decrease linearly with age. In most cases, it declines at a rate of approximately 0.5ml/kg/min per year. This is due in part to the age related decline in maximum heart rate and heart stroke volume.

Aerobic training, particularly high intensity training, can help to delay the age related decrease in VO2 max. This is likely due to the way cardiovascular training can slow the age associated decline in maximum heart rate and help to maintain stroke volume.

Gender and VO2max

Gender is also linked to VO2 max, with male athletes generally recording slightly higher values – approximately 15-30% higher than female athletes.

The difference between men and women is influenced by a number of factors including:

• Differences in %body fat,
• Muscle mass,
• Blood volume,
• Haemoglobin levels.

Genetics and physiology

As you would expect, genetics/physiology also plays a significant role, with approximately 10-30% of the variability being attributed to genetics.

Genetics appears to influence VO2max in a number of ways including:

• Cardiac output (Poole and Richardson, 1997) ,
• Muscle fibre composition (percentage of type 1, Type IIa and Type IIb),
• Body size, Muscle mass and body fat %,
• Mitochondrial density,
• Aerobic enzyme levels,
• Capillary density,
• Lung capacity,
• Viscosity of the blood
• Concentration of red blood cells.

Genetics also influences how well we adapt to training. Some individuals show a greater level of training adaptation. And, even if two athletes follow exactly the same training plan, there can be significant differences in how they adapt to this training. The differences in training adaptation can be seen both in the short term and long term.

Altitude

Altitude can affect VO2max on two levels.

Firstly, the decreased air pressure at altitude reduces the availability of oxygen, which in turn decreases aerobic capacity. So when at altitude we see a decrease in aerobic capacity compared with when at sea level. The extent of this decrease accelerates with increasing altitude.

Interestingly, there can be wide individual variation in the effect of altitude, with larger decreases typically being observed in athletes with a higher VO2max (recorded at sea level).

A secondary effect of altitude, is that the adaptations that occur following sufficient exposure to altitude, can lead to increased aerobic capacity at sea level.

Bodytype/body composition

Since VO2max is normally expressed relative to bodyweight, any variation in bodyweight will affect it. In this way, athlete’s with a large bodymass (even if it’s lean bodymass) tend to record lower values than smaller athletes.

Body composition is also known to influence VO2max: an athlete with a higher % bodyfat will tend to have a lower VO2max than a similarly sized athlete with a lower % bodyfat.

So, why is bodyweight an important factor? Simply put, a lighter bodyweight allows a greater distribution of oxygen per kilogram of body mass.

Let’s consider an example:

• Athlete A: Weighs 70kg and has an absolute VO2 max of 4 Litres of oxygen per minute.
• Athlete B: Weighs 80kg and also has an absolute VO2 max of 4 Litres/minute.

Whilst they both have the same absolute Value, Athlete A’s lighter body weight means they have a higher relative VO2max of 57 vs 50 for athlete B. In this way, athlete A has a 14% greater relative oxygen uptake, compared with athlete B.

Changes in bodyweight can significantly affect VO2max values:

• A reduction in bodyweight (e.g. reduced body fat) would normally result in an increased VO2max.
• Increased bodyweight (whether that be increased body fat or muscle) would result in a reduced aerobic capacity.

This is one of the reasons why most successful endurance athletes tend to have low body weights.

The exception to this being in non-weight baring endurance sports like rowing.

Whilst the absolute value can be useful in non weight baring sports like rowing, it is less useful in sports like running, cycling or cross country skiing. Here the relative VO2 max value tends is more useful.

Training status

Training can significantly influence VO2max. The extent of any increase varies greatly between individuals but aerobic capacity can be increased by up to 20%, depending on current fitness, previous training history and your current training programme.

Despite this, highly trained elite athletes are unlikely to see further significant improvements in aerobic capacity. In most cases, further improvements in exercise performance come from improvements in the lactate threshold, % sustainable VO2 max and improved exercise economy and the speed or power at which VO2 max occurs.

Exercise Type

The type of exercise is known to affect VO2max with greater values generally recorded in weight-baring exercises (e.g. running) than non-weight-baring exercises (e.g. swimming). Another factor here is that athletes tend to record higher values in their primary sport. As an example you would expect to see a runner score higher during a running test, compared with if they underwent a cycling VO2 max test.

VO2 MAX TESTS

Most elite athletes undergo VO2 max testing in order to monitor fitness levels and sometimes for determining training zones. However, these tests are not just for the elite and can also be useful for all endurance athletes.

They can also be used for health screening as an indicator of overall cardiovascular fitness.

How the VO2 max test is performed

• In order, to accurately measure your VO2 max the test must be completed in a controlled laboratory environment. And requires special gas analysis equipment capable of accurately measuring oxygen consumption.
• Oxygen consumption is measured via a face mask, connected to a special gas analyser. This measures the total volume of inhaled air, the percentage of oxygen and CO2 in the exhaled air, and from this calculates oxygen consumption.
• The test also requires you to exercise at an intensity where you achieve VO2 max. Since, we do not know what intensity corresponds with VO2 max, sports scientists use an incremental exercise test.
• During an incremental test, exercise intensity should start at a low intensity and each time a work stage is completed, the intensity is then increased in increments – either by increasing speed (treadmill), gradient (treadmill) or power (cycling).
• Typically, intensity is increased every 30-60 seconds. However, in some cases this may be combined with a longer work interval, which allows researchers to also measure lactate levels.
• This process continues until a work stage cannot be completed.
• VO2max is then measured as the highest average VO2 recorded over a 60 second period.
• Heart rate is also recorded, allowing identification of maximum heart rate.

VO2 Plateau

One feature of a VO2max test is the way oxygen uptake increases linearly and then plateaus at higher intensities. This allows the identification of the minimum intensity required for VO2 max.

The two graphs (below) demonstrate the plateauing of oxygen consumption with increasing speed or power output. In these examples oxygen consumption increases linearly until at a given speed (running) or power output (cycling) it begins to plateau.

In some cases there may not be a plateauing of oxygen consumption. When this happens, VO2 max is recorded as the highest volume of oxygen consumed during the test (averaged over 60 seconds).

The general criteria for achieving VO2Max is:

• Levelling off of VO2 with increased work rate <150 ml/min or <2.1 ml/kg/min
• Expiratory exchange ratio > 1.1
• Post exercise blood lactate of > 8 mM
• Rated perceived exertion (RPE) > 18 (Borg 6 – 20 scale)
• If a levelling off is not observed then VO2 max is considered to have occurred if two or more of the above criteria occur.

There are also a number of field based tests that can be used as an estimate of VO2 max (see below).

Treadmill running tests

During treadmill running tests, the speed or gradient are increased incrementally. By using running speed you can then identify the velocity at VO2 max (vVO2max), which is useful for training prescription.

Cycling tests

During Cycling VO2max tests, power is used rather than speed. Again, identifying the power at VO2max is useful for training prescription.

Although the measurement of VO2 max can be useful for athletes it is primarily a measure of cardiovascular fitness. Many coaches and sports scientists view the measurement of the lactate threshold to be of greater importance for both training prescription and assessment of race fitness.

VO2max Calculation Using Field tests

There are a number of fitness tests that can be used to give an estimate of VO2max, these include:

The Cooper Test

The Cooper run test estimates VO2 max based on the distance covered during a 12 minute run. The formula for the cooper test is:

VO2 max calculation = (distance covered in 12 mins – 504.9) / 44.73

I found this test to be fairly accurate for myself:
My lab recorded VO2max = 81
My Cooper test VO2max calculation = (4020 – 504.9) / 44.73 = 78.6

The Cooper test is not accurate for everyone, especially those with particularly good running efficiency. It’s also far less accurate for those who participate in other sports such as swimming or cycling.

HRmax and HRrest Ratio

The ratio between HRmax and HRrest can be used to estimate VO2 max (Uth et al., 2004). In this method you divide your maximum heart rate by your resting heart rate and multiply this by 15 to get an estimate of VO2max.

For me this tended to overestimate my VO2max predicting it to be 87ml/kg/min ([197/34]*15 = 86.9) however it is more applicable across multiple sports than the cooper test.

The Balke Test

The Balke Test was originally proposed by Bruno Balke (Balke, B. 1963) and involved running on a track for 15mins. VO2 max is then calculated by the following:

VO2 max = 6.5 + 5*Laps completed.

This formula was then modified by Frank Horwill (Horwill F, 1991) so:

VO2max = (0.172*(distance in metres/15 – 133)) +33.3.

This method tended to underestimate my VO2 max predicting a value of around 68 (difference of 16.1%). This particular test appears to be better suited for people with good running economy (reduced oxygen consumption at given speeds) making it less likely to be accurate across other sports.

GPS Watch VO2max Calculation

A number of GPS watches now attempt to calculate VO2max.

This is based on either the relationship between heart rate and speed (running), or heart rate and power (cycling). These can be useful as a basic calculation/estimation of VO2 max, although you often see variation in the VO2max calculation on a day to day basis.

From my own experience there can be quite wide variation on a daily basis, as well as between activities. As an example, my calculated Cycling VO2 max is normally around 10 higher than my running calculation.

During a lab based max test, it would be the other way around.

HOW TO IMPROVE VO2 MAX

So, can VO2 max be improved with training?

The good news is…if you’re new to endurance/fitness training then you should be able to achieve some quite significant improvements.

• Firstly, your lungs and heart will become more efficient, which will increase your ability to uptake and transport oxygen around your body.
• Secondly, your muscles will become more fatigue resistant and efficient at consuming oxygen during exercise. This will allow you to exercise at higher intensities for longer.
• Thirdly, endurance training increases calorie expenditure, which can lead to a reduction in bodyweight. As VO2 max is linked to bodyweight, any reduction in bodyweight can help to push up your aerobic capacity.

One point to note: in order to achieve the greatest improvements, you need to train at close to your aerobic capacity. Research has demonstrated that intensive aerobic training can increase VO2 max by 10-25% (Gormley et al., 2008; Green et al., 1995; Smith and O’Donnell, 1984; Pollock 1973;).

Not everyone achieves the same improvements

Another point to note – the level of improvement can vary significantly between individuals:

• Some individuals achieve only small improvements
• Others can achieve quite significant improvements

This is believed to be primarily due to genetic factors, with some individuals having a genetic advantage. In this way some individuals show a much greater training response than others. Essentially, they have a greater level of adaptation.

Timespan of improvements

When we first start fitness training, our body adapts quickly and we often see significant improvements. Overtime, these training adaptations begin to slow down.

Although we can continue to see improvements, significant improvements in VO2 max are harder to achieve in well trained, or, elite level athletes.

Research in cross country skiers found that there was no significant change in VO2max across a training season, even though there were significant changes in both the volume and intensity of training across the season (Losnegard et al., 2012).

In fact, improvements in performance of well-trained endurance athletes tend to be more associated with an increased ability to sustain higher percentages of VO2 max, improved lactate threshold profile and exercise efficiency (Jones, 2006).

Interestingly, in one case study (Jones, 2006) the previous women’s Marathon record holder, significantly improved her running performance despite her VO2max remaining fairly constant (~70ml/kg/min) between 1992 and 2003. And over this time period, her VO2 max did not increase significantly, despite her training volume increasing from approximately 25-30miles/week up to 120-160 miles/week over the course of the case study.

Should you train to improve aerobic capacity?

If you’re new to fitness/endurance training then improving aerobic capacity should be an important target, especially as it’s known to be a key predictor of overall health.

As we’ve seen, highly trained and elite level athletes, are much less likely to achieve improvements in VO2 max.

But here’s the thing: the training methods used to improve VO2 max are highly effective for improving endurance exercise performance.

So, even if these may not lead to significant improvements in VO2max they will improve exercise performance, and should still form a key part of endurance training.

Let’s take a look at the current recommendations for improving your VO2 max:

1. Increase Training volume

One way to improve your VO2 max is to increase your training volume. As an example, completing 4 workouts per week is more beneficial than completing 2 workouts.

Having said that, the benefit from increasing training volume begins to diminish as training volume continues to increase. And, completing more than 6-7hours of aerobic training per week is not believed to result in further increases in VO2max.

Whilst, large training volumes may not significantly improve VO2 max in elite athletes; it’s an important approach for improving exercise efficiency, lactate threshold and the sustainable %VO2max. As such, all endurance athletes should include significant amounts of low and moderate intensity training to maximise their endurance potential.

One other advantage of high volume training is decreased body fat percentage, which as we’ve seen can improve your VO2 max. Another advantage, is improved recovery from exercise.

2. Include Interval training

High intensity interval training – is believed to be one of the best training methods for improving VO2 max.
The benefit from interval training comes from the increased levels of physiological stress placed on the cardiovascular, muscular and aerobic energy systems. The increased training stress, then leads to improved adaptation in the respiratory, cardiovascular and muscular systems.

In fact, amongst well trained endurance athletes, interval training is considered to be the best way to bring about further improvements in VO2 max. It’s also one of the most time effective training methods for developing cardiovascular fitness.

What intensity should you use?

The most important factor is to ensure that intensity is near to VO2 max intensity (ideally above 90% of VO2max). If you’re not sure what this is: VO2max intensity is an intensity that can normally be sustained for around 6-9minutes during intense exercise.

As an approximate guide:

• 3km running pace is close to 100% VO2max
• 5km running pace is close to 95% VO2max
• 10km running pace is close to 90% VO2max

One point to note: this depends on your running speed. For instance, a 30minute 10k runner will be running at a higher percentage of VO2max than a 60minute 10k runner.

Here’s some example running interval sessions to develop aerobic capacity:

Longer VO2 max intervals: 

• *4-5 x 3minute intervals at 3km running pace, separated by 3minutes of low intensity exercise
• *5-6 x 3minute intervals at 5km running intensity, separated by 90seconds of easy running
• *4-6 x 5minute intervals at 10km running intensity, separated by 75-90seconds of easy running
• *Long hill VO2 max intervals

Shorter intervals:

• *10-12 x 60seconds at 3km running pace, 60seconds easy
• *2-3 x (10 x 30seconds at Mile/3km running pace, 30seconds easy), 3-5mins easy between sets
• *Short hill repeats

*These should only be completed, if you have a good level of training experience. Always, include a good warm up before completing any intense training session.

3. Altitude training/simulated altitude

Altitude training has been popular amongst elite endurance athletes looking to improve VO2 max and enhance endurance exercise performance at sea level.

This is mainly due to the increased stimulation of red blood cell production following exposure to altitude. However, the benefits of living and training at altitude are controversial mainly due to the decrease training intensity at altitude.

Research suggests that a better approach is to either, live at altitude whilst training at sea-level, or, to utilise simulated altitude tents (Levine and Stray-Gundersen, 1997;Bonetti and Hopkins 2009) although it should be noted that there appears to be a minimum exposure of 12h/day required for stimulation of erythropoiesis (red blood cell production) at altitude (Millet et al., 2010).

Final thoughts on improving VO2 max

VO2 max is clearly an important predictor of health, endurance exercise performance, and is linked to improved recover after training.

It’s important to remember, that VO2max does not appear to significantly improve amongst elite, or highly-trained athletes. As such, coaches should consider the extent to which they are using training to specifically target VO2 max.

Despite this, there are clear benefits to training at VO2 max intensities. And, while these can bring about quick training adaptations, we know less about the longer term training benefits. In fact, most research has only used very short term interventions (typically just 4-week interventions).

From my own experience VO2 max interval training can led to very quick adaptations. And often, just a few weeks training can yield significant results. For this reason, VO2 max intervals can prove particularly useful in the build up to important races. They should also feature within all phases of training. And even during base training.

One point here: this doesn’t always lead to improved endurance performance, particularly in events of greater than 30mins duration.

As with everything, we don’t all gain the same training benefits from interval training. And with this in mind, it’s important to also remember that most research looks at the average response and not the individual response to training. As such, some athletes may achieve greater long term progression through lactate threshold training and sub-maximal intervals.

Having said that, including VO2max training is clearly beneficial, it just needs to be considered as part of the larger training picture.

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VO2 Max Summary

• VO2 max is the maximum amount of oxygen that can be absorbed, transported and consumed during a given physical activity. It’s normally expressed relative to bodyweight (militres of oxygen per kilogram bodyweight [ml/kg/min]).
• Untrained individuals may have VO2max figures in the region of 25-40ml/kg/min, whereas elite endurance athletes often achieve substantially higher values in the range of 60-85ml/kg/min.
• Since it’s expressed relative to bodyweight any change in bodyweight can affect VO2 max values.
• Your VO2max is influenced by a number of factors including age, gender, genetics, physiology, body-type/body-composition, training status, and exercise type.
• It’s normally established during a laboratory based incremental exercise test in which the speed/workrate is increased, until the oxygen uptake peaks, or there is a levelling off (plateau) in the oxygen uptake.
• A number of field tests (Cooper test, Balke test, ratio between HRmax and HRrest) have been established to calculate your VO2max, although the accuracy of these tests has been questioned and they tend to produce varied results.
• VO2max can be significantly increased in the untrained or moderately trained.
• The greatest improvements occur with high intensity interval training – although the level of increase appears to be affected by genetic factors.
• Significant increases in VO2max appear to be unlikely in well trained or elite athletes.
• A high VO2max appears to enhance recovery rates after exercise.

References

BALKE, B. (1963) A simple field test for the assessment of physical fitness. Rep Civ Aeromed Res Inst US. 1963 Apr:1-8. PMID, 14131272

Bonetti DL, Hopkins WG. (2009) Sea-level exercise performance following adaptation to hypoxia: a meta-analysis. Sports Med. 2009;39(2):107-27. doi: 10.2165/00007256-200939020-00002.

Conley, D.L. and Krahenbuhl, G.S. (1980). Running economy and distance running performance in highly trained athletes. Medicine and Science in Sports and Exercise, 12, 357-360.

Daniels, J. and Daniels, N. (1992). Running economy of elite male and elite female runners. Medicine and Science in Sports and Exercise, 24, 483-489.

Fallowfield, J.L. and Wilkinson, J.L. (1999). Improving sports performance in Middle and Long-Distance Running. Chichester: John Wiley and Sons, LTD.

Gormley SE, Swain DP, High R, Spina RJ, Dowling EA, Kotipalli US, Gandrakota R. (2008) Effect of intensity of aerobic training on VO2max. Med Sci Sports Exerc. 2008 Jul;40(7):1336-43. doi: 10.1249/MSS.0b013e31816c4839.

Green HJ, Jones S, Ball-Burnett M, Farrance B, Ranney D. (1995) Adaptations in muscle metabolism to prolonged voluntary exercise and training. J Appl Physiol. 1995 Jan;78(1):138-45.

HORWILL, F. (1991) Obsession for Running – A Lifetime in Athletics. London: Colin Davies Printers

Jacobs RA, Rasmussen P, Siebenmann C, Díaz V, Gassmann M, Pesta D, Gnaiger E, Nordsborg NB, Robach P, Lundby C. (2011) Determinants of time trial performance and maximal incremental exercise in highly trained endurance athletes. J Appl Physiol. 2011 Nov;111(5):1422-30. Epub 2011 Sep 1.

Jones AM (2006). The physiology of the world record holder for the women’s marathon. Int J Sports Sci Coaching 1,101–116.

Levine BD, Stray-Gundersen J. (1997) “Living high-training low”: effect of moderate-altitude acclimatization with low-altitude training on performance. J Appl Physiol. 1997 Jul;83(1):102-12.

Losnegard T, Myklebust H, Spencer M, Hallén J. (2012) Seasonal variations in VO2max, O2-cost, O2-deficit and performance in elite cross-country skiers. J Strength Cond Res. 2012 Sep 19. [Epub ahead of print]

Marcell TJ, Hawkins SA, Tarpenning KM, Hyslop DM, Wiswell RA. (2003) Longitudinal analysis of lactate threshold in male and female master athletes. Med Sci Sports Exerc. 2003 May;35(5):810-7.

Matsuo T, Ohkawara K, Seino S, Shimojo N, Yamada S, Ohshima H, Tanaka K, Mukai C. (2012) Cardiorespiratory fitness level correlates inversely with excess post-exercise oxygen consumption after aerobic-type interval training. BMC Res Notes. 2012 Nov 21;5:646. doi: 10.1186/1756-0500-5-646.

Millet GP, Roels B, Schmitt L, Woorons X, Richalet JP. (2010) Combining hypoxic methods for peak performance. Sports Med. 2010 Jan 1;40(1):1-25. doi: 10.2165/11317920-000000000-00000.

Morgan, D.W., Baldini, F.D., Martin, P.E. and Kohrt, W.M. (1989). Ten kilometer performance and predicted velocity at VO2max among well trained male runners. Medicine and Science in Sports and Exercise, 21, 78-83.

Noakes, T.D. (1991). Lore of Running. Human Kinetics: Champaign, IL, USA.

Poole, D.C. and Richardson, R.S. (1997). Determinants of oxygen uptake. Sports Medicine, 24, 308-320.

Pollock ML. (1973). Quantification of endurance training programs. Exercise and Sport Sciences Reviews. 1,155-188

Smith, D. A. & O’Donnel, T. V. (1984). The time course during 46 weeks’ endurance training of changes in Vo2max and anaerobic threshold as determined with a new computerized method. Clin Sci, 67(2), 229–236.

Uth N, Sørensen H, Overgaard K, Pedersen PK. (2004) Estimation of VO2max from the ratio between HRmax and HRrest–the Heart Rate Ratio Method. Eur J Appl Physiol. 2004 Jan;91(1):111-5. Epub 2003 Nov 18.

Wiswell RA, Jaque SV, Marcell TJ, Hawkins SA, Tarpenning KM, Constantino N, Hyslop DM. (2000) Maximal aerobic power, lactate threshold, and running performance in master athletes. Med Sci Sports Exerc. 2000 Jun;32(6):1165-70.