Bookmark Website  | Free Registration  | The Team
The Lounge  | Champions  | The Wire |  Schedule |  Audio  |  Arcade  |  The Top Ten  |  Historical  |  Email  |  Video

VO2 Max- Exposing the Myth


VO2 max is defined as the maximal amount of oxygen the body is able to extract and use to support work performed by the body. It is therefore an indirect measure of the aerobic power of the body, which is controlled by complex interactions between neural (brain and nervous system), cardiovascular (heart and lungs) and skeletal muscle factors. The equation for VO2 max it is equal to the product of stroke volume (the maximum volume of blood the heart ejects in a contraction) and the arterio-venous difference (the difference between the saturation of the arterial blood and that of the venous blood). The aerobic power of the body will change constantly throughout a well-designed running program due to physiological changes and therefore its usefulness in designing a program and determining running capabilities is questionable. This article aims to explain the reason VO2 max is a better indicator of fitness levels than running potential and conditioning program design.

Many physiological adaptations occur as one becomes more fit, some of these include: an increased size and efficiency of the heart, increased blood volume, increased muscle capillarization (more capillaries developed) and increased mitochondria (small bodies in the muscle cell that use oxygen to burn fat and make energy) density. So it should be obvious then that if we increase the stroke volume or the a-v difference (or both), the VO2 max will increase. With a more muscular heart and an increased blood volume you may increase the stroke volume and with a greater extraction of oxygen from the blood at the muscle level (more mitochondria) you can increase the a-v difference, which equals a higher VO2 max. Thus, VO2 max is a good indicator of physical condition or fitness.

The question arises whether it is beneficial to know your VO2 max to develop an ideal training regimen or whether a high VO2 max automatically determines you as a great runner. From evidence accumulated by Prof. Tim Noakes and his colleagues at the Sports Science Institute of South Africa the answer is that knowing your VO2 max will not answer either question. Here's the explanation according to Dr. Andrew Bosch at the Institute. Dr Bosch questions whether VO2 max is genetically determined (i.e. an athlete with a high value has muscles that are capable of utilizing large amounts of oxygen and has a cardiovascular system capable of delivering this quantity of oxygen). This athlete can then run at a maximum aerobic speed that can be sustained by this amount of oxygen. If VO2 max was determined genetically, then it would make no difference if the athlete was highly unfit or superbly fit since the result of the test would be the same. However, it should be intuitively obvious that a fit and more conditioned runner can run at a higher speed (higher power output) on a treadmill than when unfit. Dr. Bosch suggests that in this situation the (high) VO2 max value would be attained at a very low running speed, which would be impossibly inefficient.

Dr. Bosch confirms the common knowledge that oxygen demand increases incrementally as the speed (power output) of the runner increases. This increase in oxygen consumption continues until the athlete can no longer continue running at that speed and stops. The volume of oxygen consumed at that instant is termed the VO2 max and the running speed, the peak running speed. Historically, exercise scientists have attributed a leveling out or a plateau to VO2 max and that at the point this occurs determines the value. Research by Noakes and colleagues indicate that half of athletes tested in laboratories fail to demonstrate a plateau and that their VO2 or oxygen consumption is still increasing when they cannot continue further. This poses a question as to why these runners stopped if their oxygen consumption (the supposed limiting factor) was still on the increase. Prof. Noakes feels and is continuing to search for evidence that some "central governor" regulates the power output to the exercising limbs to help protect the body from "running itself to death" via a heart attack (see VO2 Max or the Brain?). The fact that oxygen consumption continues to increase until ultimate fatigue indicates that as the fitness level of the athlete increases and he is able to run faster, so does his VO2 max. Therefore, the inability to use the VO2 max test as a predictor of future performance of an athlete that can still improve his running by using a scientifically devised program becomes obvious - a great training induced increase in running speed (decrease in race times) will transfer into a substantial increase in VO2 max and visa versa. Even knowing the peak speed is unlikely to help an individual for the same reasons and also possibly because of the unlikelihood of being able to sustain such a speed/intensity for the duration of a long distance run.

Professor Tim Noakes feels that running economy is the true measure of performance. Running economy is the relationship between maximal power output and oxygen consumption. Good running economy in this context means that a highly economical runner may actually achieve a higher treadmill speed or power output at a relatively low VO2 max and is therefore more efficient. A less economical runner will require a higher volume of oxygen to achieve the same power output. Noakes is proposes that biomechanical efficiency contributes to running economy - for example, a runner with good core stability will waste less energy and power than a competitor with poor core strength that allows for inefficent movement. Also, Dr. Noakes considers superior runners to have superior fatigue resistance. That is, they have a superior heart that can maintain a high cardiac output at the maximum coronary blood flow and skeletal muscles that are efficient, elastic and possess a high degree of contractility.

Dr. Bosch concedes that even though it may be of little use in predicting running ability or program design, there are some uses for the VO2 max test. He advises that if a program is being designed for a beginning runner who has not run any races and therefore has no running times, a VO2 max test will give a good indication of the current condition of the athlete and how to base running schedules. Also, if performed regularly, a VO2 max test can give an indication of the effectiveness of the training program. Lastly, it is fun to compare own VO2 max to those of elite runners who often have values exceeding 70ml/kg/min.

David Petersen is a Personal Trainer/Certified Strength and Conditioning Specialist and the owner and founder of B.O.S.S. Fitness Inc. based in Oldsmar, Florida. More articles and information can be found at http://www.bossfitness.com

NOTE: You're free to republish this article on your website, in your newsletter, in your e-book or in other publications provided the article is reproduced in its entirety, including this note, author information and all LIVE website links as above.


MORE RESOURCES:

New York Times (blog)

Exercise to Lose Weight? Stay Warm
New York Times (blog)
Noting these inconsistencies, researchers at the University of Aberdeen in Scotland and the University of Birmingham in England began to wonder whether the ambient temperature in which people exercise might affect their appetite and eating habits ...



CBS News

The best exercise for controlling belly fat
CBS News
Men who did regular weight-training had less gain in their waistline (-0.67 cm) over the 12-year period, compared with those who participated in moderate-to-vigorous aerobic exercise (-0.33 cm), or physical labor from daily life such as yard work or ...
An Unexpected Exercise That Targets Belly FatHuffington Post
Stay in shape over the holidays: 3 exercise toys to take on a tripToday.com
Using weights to target belly fatHarvard Gazette
Live Science
all 80 news articles »


Asthma & Exercise
The Daily Advertiser
Known as exercise-induced asthma, or exercise-induced bronchoconstriction (EIB), the condition can be managed and should not interfere with an exercise program. If you experience wheezing, coughing, shortness of breath, a tightness in the chest, during ...



Will exercise & nutrition slow down early puberty?
Philly.com
BEING THE mother of a 6-year-old, I go to lots of children's birthday parties. I've been noticing a phenomenon called precocious puberty, which hits girls especially hard, though increasingly I've noticed it in boys, too. I'll find myself thinking ...

and more »


Body Shop | Moderate versus vigorous exercise
The Courier-Journal
Time to get back in shape, and that means exercise. This week, I begin a four-part series on exercise that is intended to help you make choices best suited for you. Is jogging and other forms of vigorous exercise the only approach that works, or can ...



Why You Need to Exercise Much More Than Your Ancestors Did
Healthline
Why You Need to Exercise Much More Than Your Ancestors Did. Our ancestors, who had to hunt and gather their food before the invention of agriculture, were more physically active than we are. Their bones were much stronger, too. Written by Nina Lincoff ...

and more »


UPI.com

Mind over matter, the brain alone can tone muscle
UPI.com
24 (UPI) -- New research suggests muscles respond to simple thoughts of exercise; simply imagining exercise can trick the muscles into delaying atrophy and even getting stronger. It's further proof that brain and body, which evolved together, are more ...
Muscles Can Get Stronger by Imagining Exercises, Study FindsHeadlines & Global News
Mind over matter, brain alone can tone muscleWND.com

all 5 news articles »


Fox News

Exercise tied to prostate cancer survival
Fox News
Among men with prostate cancer, those who lead active lifestyles have better survival rates than those who don't, a new study suggests. There are many benefits to being physically active, but the new results suggest there are “specific effects also on ...
Lower Death Rates in Men With Prostate Cancer Who ExerciseMedscape

all 20 news articles »


Design & Trend

How Does Exercise Affect Our Genes?
Design & Trend
We are all aware of the health benefits of exercise and how they reduce the risks of certain diseases. However, scientists are uncertain what impact exercise has on our genes. In a new study, researchers at the Karolinska Institute in Stockholm have ...
How exercise changes our DNADeccan Herald

all 2 news articles »


Care2.com

5 Tips for Successful Winter Weather Exercise
Care2.com
While cuddling around a fireplace or TV with a cup of hot cocoa may seem tempting when the temperature drops during the winter, exercising in the crisp, cool air can be good for you. An article in Women's Health quotes Kevin Plancher, M.D., head of ...


Google News


Advertisement



Section Site Map - Submit News - Feedback - Comments - Advertise with Us

Copyright © 2006 Luminati Inc. All rights reserved.