Blair: We all possess the capability for anaerobic and aerobic energy metabolism. By definition, anaerobic metabolism doesn’t require oxygen for energy i.e., for immediate and short-term exercise. Aerobic metabolism uses oxygen as it’s main energy source. The capacity for each varies considerably among individuals and this between-individual variability underlies the concept of individual differences in metabolic capacity for exercise. A person’s capacity for energy transfer is not simply a general factor, but is highly dependent on the form of exercise with which it is trained and evaluated.
A high oxygen uptake in running, for example, doesn't necessarily assure a similar metabolic power when different muscle groups are activated, as in swimming, cycling, or rowing. The effects of systematic training are highly specific in terms of neurologic, physiologic, and metabolic demands.
Maximum oxygen uptake, also called V02 max or max V02 is a measure of aerobic fitness. Maximum oxygen uptake is simply the maximum capacity for oxygen consumption by the body during maximum exertion. V02 max is a commonly used determinant of aerobic (cardiovascular) fitness and provides important information on the power of the long-term energy system. . Aerobic fitness relates to how well your cardiovascular system works to transport and utilize oxygen in your body. The better your aerobic fitness the higher your V02 max.
This is not to say that V02 max is the only determinant of aerobic work capacity. Other factors, especially those at the muscular level, such as the number of capillaries, enzymes, and muscle fiber type, exert a strong influence on the capacity to sustain high levels of aerobic exercise.
Distance runners, swimming, cyclists, and cross-country skiers have some of the highest V02 max levels recorded. Measurement of V02 max has become one of the fundamental measures in exercise physiology. The most accurate way to measure your V02 max is to perform a maximal exercise stress test in a laboratory but some field tests can estimate (with a certain degree of variability) what a person’s maximum aerobic capacity is. Field tests for predicting V02 max should be viewed with caution but can provide valuable information in the absence of more valid laboratory methods.
V02 max is influenced by many factors. Of these, the most important appear to be the mode of exercise used to evaluate V02 max, heredity, state of training, age, sex, and body composition. Each factor contributes uniquely to an individual’s V02 max.
The question is frequently raised concerning the relative contribution of heredity on exercise performance. Some research has concluded heredity alone can account for 93% of the observed differences in aerobic capacity as measured by V02 max. In addition, the capacity of the short-term energy system (anaerobic metabolism) was shown to be genetically determined by about 81 to 86%. This data was researched using 15 pairs of identical twins and 15 pairs of fraternal twins. It is possible that these estimates represent the upper limit of genetic determination, but the data do suggest that the aerobic systems are significantly influenced by factors related to heredity.
Recent studies have shown that not only is our starting point genetically determined, but also our adaptability to training (how much we improve) is quite variable and genetically influenced.
Never the less, at any level of competition, it may be the effect of training that determines superior performance in aerobic activities.
Measuring V02 max will help an individual ensure that their training is at the correct intensity and will help achieve better results. Furthermore, regular testing throughout the season can be beneficial to tracking and quantifying progress.
V02 testing only works when the individual comes away with a clear understanding of how and why the training approach needs to be altered to improve performance. This requires an individual with the expertise and time to educate the client on the meaning of their results and the implication of those results on personal training goals.
Most of the athletes who have a tendency to push into their anaerobic zone, at almost every workout, and then go home are those that don't know what their bodies really need in order to improve. And these are the kids who's performances have kind of flatlined...not improving. Kind of the train hard or go home type attitude. No pain, no gain. This is a particular problem with high school cross country runners, for example. Clint was having problems with Nicole and Nick always wanting to push and then push harder at every workout. Long Runs for them were races. We tested that whole group of Limestone runners 3 times over their last cross country season and were able to show them from the results that there was a time to run "easy" either aerobically or for recovery....and a time to push past their AT's. Ended up with 2 state champions that year and great overall results for the team. Clint knew how to take the results from our discussions and apply them to his runners. Physiologically their AT's and V02's were off the chart, but the numbers from the tests also gave them the confidence they needed to know they could win. Knowing when to train hard enough or easy enough is important....Greg schedules that into his plans. You aren't out there hammering all the time. Most people quite honestly have to slow down to get faster....maximize their base potential and then work on running harder. This requires patience from most runners/athletes. It's a hard concept to understand much less realize. I've had a lot of people come in, take the test, have me outline what I thought they needed and go right back to what they were doing before and wondering why they weren't improving. It's whether you can come in with an open mind and be willing to step back and take a chance so to speak. The results will speak for themselves. There is a balance between training hard and training easy that most athletes don't understand. We're doing some testing on some Bradley/Notre Dame runners right now to establish a baseline and plan to follow them throughout the season til the end of the school year. It will be interesting. I do think it's important to be re-tested on a regular basis like we did with the Limestone kids so you can track progress and tweak the training program.
Rob:Thanks. I understand VO2 a little better. You’ve got me intrigued. I would like to keep this discussion specific to running for my blog since it’s a site about kicking Schroffs A## in a marathon. Here are a few more questions spurred from your reply….(If I am completely missing one of your premises, please correct me).
1) Why do I really care about VO2? From what I understand you are saying, I cant really change it.
2) Opinion: Isn’t training to run faster at long distance a matter of achieving a higher aerobic threshold (i.e. LT)?
3) How does age and current fitness fit into this discussion (physiology)? I mean if athletic prowess is predetermined at birth, why do old fat men run slower than young skinny men?
4) If I understand you, you’re saying a high percentage of a runner’s potential VO2 is genetic. Does this mean regardless of how fit she is, she’s going to perform at a level that is nearly 90% of what she’s capable of? Does the distance of the run play into this? Do we even need to train to get most of what we are ultimately capable of? (I know it’s really 3 questions J)
5) How does LT play into this discussion? Is it simply the point of exercise intensity where we go from an aerobic to an anaerobic state?
6) I have an (perhaps irrational) fear of being tested. What if I come in and you test me and tell me the fasted marathon I will ever run is 2 hours and 57 minutes. I am not sure I want to be told that. What would you tell me?
Blair:
V02 Max -- First, all of your endurance training depends on you developing your aerobic base (V02 max) to it’s fullest. If your V02 max is relatively high, your measure of improvement may not be that great 2-5% at most. Remember these adaptations in V02 max depend on the type of overload imposed. The specificity principle states that if you want to improve as a runner this is most effectively achieved when the exerciser trains the specific muscles involved in the desired performance i.e., running. Truly, specific exercise elicits specific adaptations creating specific training effects. Of note, even when you develop your V02 to it’s maximum potential; improvements in performance are supported by other mechanisms only partly related to the oxygen transport system. In some tests you may see only a slight increase or no change in V02 max, but an increase in maximum work time to reach that value. So there is a partial independence of performance measures from physiologic measures which may explain why V02 max values of certain endurance athletes in the 1930’s and 40’s were similar to those of present day athletes, even though the performances of contemporary athletes substantially exceed those of athletes from that era. This illustrates that a clear distinction be made between physiologic and performance changes with training. So even though V02 max may peak, performance need not have to.
Knowing your V02 max will give you the proper training intensity to maximize your base fitness. Staying in the appropriate training zones will allow your body to chew up your fat reserves for fuel instead of simply relying on that day’s carbohydrate intake. Why? Your body has up to 50 times more energy dammed up in its fat stores than the measly 2,000 carbohydrate calories that can be stored as glycogen. Tap the fat, and you’re likely to see improvements in both body-fat composition and performance. The more aerobically fit you are, the higher percentage of fat you’re burning at every level of intensity. The increase efficiency will show up in faster times, achievable at the same heart rate.
Training at these zones requires some getting use to. It takes an entirely different mental approach. Most athletes, both recreational and elite, warm up for their workout, get to feeling OK, and then push it into their anaerobic zone so they can go home and say they got a good workout. They don’t train hard enough or easy enough, and so they’re stuck in a perpetual no-man’s land. The bottom line is, to train aerobically requires patience: The emphasis is long-term gain, not immediate gratification.
Anaerobic Threshold (AT) -- there exists an effort level called the anaerobic threshold (AT) steady state than an athlete can continue at for an extended period of time without having to slow down, usually and hour but sometimes longer. As long as the athlete maintains this effort level his or her lactate level with remain constant. At small effort levels above this point the athlete’s lactate level will rise slowly and he or she will be forced to stop, sometimes within a few minutes or sometimes after and extended period of 20-30 minutes. Above this AT steady state there are no more steady states but an inevitable and frequently rapid progression to exhaustion.
The AT is the single best indicator of endurance performance known. Generally the athlete with the maximal AT steady state at the higher effort level (speed or power) will be faster in an endurance event. Increases in AT steady state are almost always accompanied by improvements in race performance in endurance events. So frequent AT testing (every 4-6 weeks) is usually the best indicator or potential race performance for endurance events. It is also generally the best measure for improvements due to training or a lack of response to training. For short events the maximal AT steady state is also highly correlated with performance but anaerobic capacity or the ability to produce lactate and speed will become more important as the events get shorter.
Training at AT or higher is very stressful and can be a formula for over-training and/or injury. Very often endurance athletes do not feel much stress when training at AT or higher but this can be deceiving as the stress they are putting on the aerobic system at these high intensities can break down this system too much and result in less aerobic capacity, not more. That is why is essential to first build a strong aerobic/endurance base before introducing this type of training into your program. Once the foundation is built, the athlete can start to add in training above their AT.
V02 variables---SEX --V02 max values are typically higher for men than women even among trained athletes (15 to 30%). This is generally attributed to differences in body composition and hemoglobin levels. The aerobic capacity of active females is typically higher than that of sedentary males.
BODY COMPOSITION -- It is estimated that 69% of the differences in V02 max scores among individuals can be explained by differences in body weight, 4% by differences in height, and 1% by variations in lean body weight. This is why oxygen consumption is expressed in terms of body size (ml – kg – min).
AGE – After age 25, the max V02 steadily declines although active adults retain a relatively high V02 max at all ages.
V02 max is not the only variable that determines endurance running performance. Multiple factors such as body weight and body fatness, running efficiency, nutrition, motivation, and the percentage of one’s aerobic capacity that can be sustained without lactic acid buildup all contribute significantly to successful running.
As far as telling you your fastest marathon is 2:57…..I don’t think one can accurately predict what an individual’s optimum level of performance is based solely on measuring his V02 max. I know I can’t. There’s too much else that needs to be factored in.
Rob:
When you say they don’t work hard enough is that because they go Anaerobic and are forced to stop too soon? If they picked a slower pace, they would be able to work longer? Is that what you mean by patience?
Blair:
Most of the athletes who have a tendency to push into their anaerobic zone, at almost every workout, and then go home are those that don't know what their bodies really need in order to improve. And these are the kids who's performances have kind of flatlined...not improving. Kind of the train hard or go home type attitude. No pain, no gain. This is a particular problem with high school cross country runners, for example. Clint was having problems with Nicole and Nick always wanting to push and then push harder at every workout. Long Runs for them were races. We tested that whole group of Limestone runners 3 times over their last cross country season and were able to show them from the results that there was a time to run "easy" either aerobically or for recovery....and a time to push past their AT's. Ended up with 2 state champions that year and great overall results for the team. Clint knew how to take the results from our discussions and apply them to his runners. Physiologically their AT's and V02's were off the chart, but the numbers from the tests also gave them the confidence they needed to know they could win. Knowing when to train hard enough or easy enough is important....Greg schedules that into his plans. You aren't out there hammering all the time. Most people quite honestly have to slow down to get faster....maximize their base potential and then work on running harder. This requires patience from most runners/athletes. It's a hard concept to understand much less realize. I've had a lot of people come in, take the test, have me outline what I thought they needed and go right back to what they were doing before and wondering why they weren't improving. It's whether you can come in with an open mind and be willing to step back and take a chance so to speak. The results will speak for themselves. There is a balance between training hard and training easy that most athletes don't understand. We're doing some testing on some Bradley/Notre Dame runners right now to establish a baseline and plan to follow them throughout the season til the end of the school year. It will be interesting. I do think it's important to be re-tested on a regular basis like we did with the Limestone kids so you can track progress and tweak the training program.
Blair T. Gorsuch, MS
Exercise Physiologist
Director, Cardiac Rehabilitation
Proctor Hospital
5405 N. Knoxville Ave. #1
Peoria, IL 61614
