Changes

[[File:VO2max.jpg|right|thumb|x200px|A graph showing that O₂ consumption increases with exercise intensity until a maximum is reached, which is V̇O₂max.]]V̇O₂max is the maximum (max) volume (V) of oxygen (O₂) you can use during exercise. Measuring V̇O₂max requires specialist equipment, but there are many locations with the facilities and the cost is usually under $100. The procedure involves running on a treadmill while wearing a mask to capture your breath. There is a warm up period, and then you run at a reasonably stressful pace while the treadmill gradient is steadily increased until you can't keep going. For most of the test, as the workload increases so does the O₂ you use. However, there will come a point where the increased workload does not have a corresponding increase in O₂ usage. This is the point where you are using as much O₂ as you are capable of and you the increased workload is coming from anaerobic systems. While V̇O₂max is interesting, it does not include details of [[Running Economy]], so it does not give a complete picture of a runner's capabilities. Arguably, [[VDOT]] is a more useful measure of fitness.=Estimating VO2max=V̇O₂max can be estimated from a race performance, and this is implemented in the [[VDOT Calculator]]. Another approach is the Cooper test developed in 1968 found that the distance that could be covered in 12 minutes was strongly correlated with VO2max<ref name="Cooper1968"/>. However, the Cooper test requires a lot of [[Motivation|motivation]] and a good sense of pacing, as 12 minutes is a relatively long period for this type of test<ref name="Billat-1996"/>. A similar technique is to increase running speed every two minutes until exhaustion, then VO2max can be estimated from the maximum speed that was achieved using Léger & Mercier formula:<ref name="Léger-1984"/>: V̇O₂max = speed * 3.5Where V̇O₂max is in ml/Kg/min and vV̇O₂max is in km/hr. =V̇O₂max and V̇O₂peak=[[File:VO2peak.jpg|right|thumb|x200px|This graph shows that V̇O₂peak, which is the highest O₂ observed, without the plateau that defines V̇O₂max.]]Some research uses the term V̇O₂peak rather than V̇O₂max, and while the two are similar, there is an important difference. Where V̇O₂max is the highest O₂ uptake seen, even though exercise intensity has continued to increase, V̇O₂peak is simply the highest O₂ seen<ref name="Whipp"/>. It's possible for V̇O₂peak to be the same as V̇O₂max, but only if the test is terminated at just the right point. The biggest problem with V̇O₂peak is that a training program might result in a subject getting better at the test, which would result in a higher V̇O₂peak value, without actually changing their V̇O₂max. For instance, I might have a V̇O₂max of 60, but find the testing protocol so hard that I give up when my V̇O₂ reaches 50 which would only give a V̇O₂peak value. If I do some high intensity training, I'd be more comfortable at these high workloads and I might reach a V̇O₂peak of 55, which would look like a 10% improvement, but is actually not a change in physical fitness.

The velocity that is reached at V̇O₂max is called [[vVO2max| vV̇O₂max. An approximation of ]], and the time that [[vVO2max| vV̇O₂max ]] can be sustained for is the mile race pace, but a more accurate formula is shown below<ref name="Léger-"/>.  vV̇O₂max = V̇Ocalled T_2limmax /3.5 Where V̇Oor T₂max is in ml/Kg/min and vV̇O₂max is in km/hr.   

<ref name="LégerWhipp">THE PEAK VERSUS MAXIMUM OXYGEN UPTAKE ISSUE, Brian J. Whipp, Ph.D., D.Sc., Institute of Membrane and Systems Biology, University of Leeds,Leeds, UK</ref><ref name="Cooper1968">Kenneth H. Cooper, A Means of Assessing Maximal Oxygen Intake<subtitle>Correlation Between Field and Treadmill Testing</subtitle>, JAMA: The Journal of the American Medical Association, volume 203, issue 3, 1968, pages 201, ISSN [http://www.worldcat.org/issn/0098-7484 0098-7484], doi [http://dx.doi.org/10.1001/jama.1968.03140030033008 10.1001/jama.1968.03140030033008]</ref><ref name="Billat-1996">{{Cite journal | last1 LV. Billat, JP. Koralsztein, Significance of the velocity at VO2max and time to exhaustion at this velocity., Sports Med, volume 22, issue 2, pages 90-108, Aug 1996, PMID [http://www.ncbi.nlm.nih.gov/pubmed/8857705 8857705]</ref><ref name= "Léger | first1 = -1984">L. | last2 = Mercier | first2 = Léger, D. | title = Mercier, Gross energy cost of horizontal treadmill and track running. | journal = , Sports Med | , volume = 1 | , issue = 4 | , pages = 270-7 | month = | year = | doi = | , PMID = [http://www.ncbi.nlm.nih.gov/pubmed/6390604 6390604 }}]</ref>