is the measurement of maximal oxygen intake passe

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thinks about the balance of sedentary behaviour and activity in all aspects of daily life, including transport, occupa-tional settings, domestic work and leisure,especially around obesity managementand the role of total physical activity inthe prevention of further weight gain.This involves some re-orienting of the

physical activity and health field from itswell-established focus on LTPA to acomprehensive programme of research tounderstand the determinants of sedentary behaviour and both LIPA and MVPA. Itwill also involve studying the effects onhealth outcomes of shifting the balance of these behaviours towards more activity inall domains of daily life.

CLINICAL IMPLICATIONSGiven the recent recognition of thisphenomenon of too much sitting, there

are not yet any recommended clinicalguidelines. Commonsense might suggestthat it may be prudent to try to minimiseprolonged sitting with 5 minute breaksevery hour. However, more specific advicewill require dose-response relationshipsbetween sitting and health outcomes tobe defined using controlled studies. Many of the possible interventions that encou-rage movement may well be undertakenin settings in which prolonged periods of sedentary behaviours are the norm.

CONCLUSIONS

Research, policy and practice on physicalactivity and population health hasfocussed largely on increasing the timethat adults spend doing moderate tovigorous intensity activities; 30 minutesa day is generally the target. However,recent evidence from biomarker studiesand objective-measurement studies (andalso from some prospective epidemiologi-cal studies) highlights the importance of focusing on the balance of light-intensity activities and sedentary behaviours—par-ticularly the high volumes of time that

adults in industrialised and developingcountries spend sitting in their 15.5 ‘‘non-exercise’’ waking hours. A particular con-cern for this new research agenda is howto approach reducing or breaking-upprolonged sitting time, and how thismight relate to increasing light intensity and moderate to vigorous intensity phy-

sical activities. Other research opportu-nities include carrying out studies on howbest to promote higher volumes of overallphysical activity (light intensity activitiesin addition to moderate to vigorousintensity activities), in the context of theubiquitous environmental and social dri-vers of sitting time in occupational,transportation, recreational and domesticsettings.

Particular concerns for exercise scienceresearch agenda include identifying why sedentary behaviour and the associated

health relationships seem to be particu-larly strong for women and examining theeffects of interventions for reducing orbreaking-up sitting time. The issue of toomuch sitting has challenging implicationsfor future healthcare practice and willrequire development of new kinds of clinical and public health guidelines.18

Funding: NO, AB WB are supported by NHMRCProgram Grant funding (#301200); NO is also supportedby a Queensland Health Core Research Infrastructuregrant.

Competing interests: None.

Accepted 24 October 2008Published Online First 28 November 2008

Br J Sports Med 2009;43:81–83.doi:10.1136/bjsm.2008.055269

REFERENCES1. Daar AS, Singer PA, Persad DL, et al . Grand

challenges in chronic non-communicable diseases. Nature 2007;450:494–6.

2. Bauman A, Bellew B, Vita P, et al . Getting Australiaactive: Best practice for the promotion of physicalactivity. Melbourne: National Public HealthPartnership, 2002.

3. Bauman A, Allman-Farinelli M, Huxley R, et al .Leisure-time physical activity alone may not be a

sufficient public health approach to prevent obesity—a focus on China. Obes Rev 2008;9:119–26.

4. Healy GN, Dunstan DW, Salmon J, et al . Objectivelymeasured light-intensity physical activity isindependently associated with 2-h plasma glucose.

Diabetes Care 2007;30:1384–9.5. Anderssen SA, Engeland A, Sogaard AJ, et al .

Changes in physical activity behavior and thedevelopment of body mass index during the last 30years in Norway. Scand J Med Sci Sports

2008;18:309–17.6. Levine JA. Nonexercise activity thermogenesis—liberating the life-force. J Intern Med 2007;262:273–87.

7. Bell AC, Ge K, Popkin BM. The road to obesity or thepath to prevention: motorized transportation andobesity in China. Obes Res 2002;10:277–83.

8. Brown W, Ringuet C, Trost S. How activeare young adult women? Health Promot J Austr 2002;13:23–38.

9. Ainsworth BE, Haskell WL, Whitt MC, et al .Compendium of physical activities: an update ofactivity codes and MET intensities. Med Sci Sports

Exerc 2000;32:S498–504.10. Gunn SM, Brooks AG, Withers RT, et al . Determining

energy expenditure during some household andgarden tasks. Med Sci Sports Exerc2002;34:895–902.

11. Brown WJ, Williams L, Ford JH, et al . Identifying theenergy gap: magnitude and determinants of 5-yearweight gain in midage women. Obes Res2005;13:1431–41.

12. Healy GN, Dunstan DW, Salmon J, et al . Breaks insedentary time: beneficial associations with metabolicrisk. Diabetes Care 2008;31:661–6.

13. Booth ML, Chey T, Wake M, et al . Change in theprevalence of overweight and obesity among youngAustralians, 1969–1997. Am J Clin Nutr 2003;77:29–36.

14. Australian Institute for Health and Welfare. Areall Australians gaining weight? Differentials inoverweight and obesity among adults, 1989–90 to2001. Bulletin No. 11. AIHW Cat. No. AUS 39.Canberra: AIHW, 2003.

15. Venn AJ, Thomson RJ, Schmidt MD, et al .Overweight and obesity from childhood to adulthood:a follow-up of participants in the 1985 AustralianSchools Health and Fitness Survey. Med J Aust 2007;186:458–60.

16. Hu FB, Willett WC, Li T, et al . Adiposity as comparedwith physical activity in predicting mortality amongwomen. N Engl J Med 2004;351:2694–703.

17. Brown WJ, Hockey R, Dobson A. Rose revisited: a‘‘middle road’’ prevention strategy to reducenoncommunicable chronic disease risk. Bull World

Health Organ 2007;85:886–7.18. Hamilton M, Healy G, Dunstan D, et al . Too little

exercise and too much sitting: Inactivity physiologyand the need for new recommendations on sedentarybehaviour. Current Cardiovascular Risk Reports2008;2:292–8.

Is the measurement of maximaloxygen intake passe?

Roy J Shephard

A recent and controversial review1 sug-gests that the measurement of maximal

oxygen intake is passe. The author con-cludes (p. 554) ‘‘ It is now time to developnovel testing methods....That the measured

VO2max is a relatively poor predictor of boththe performance potential of athletes with

similar athletic ability and of the changes in performance that occur with continued train-ing should encourage both basic and applied

sports scientists to reconsider the real value of this iconic test.’’

A number of the arguments that areadvanced in this review seem to needcorrection or refutation. Specifically, thisriposte will examine whether a maximaltreadmill test is an unrealistic procedure forathletes, whether a unimodal approach to

testing is appropriate in sports medicine,and whether an alternative laboratory test

Correspondence to: Roy J Shephard, PO Box 521,Brackendale, Canada BC V0N 1H0; [email protected]

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Br J Sports Med February 2009 Vol 43 No 2 83



will be developed to categorise the perfor-mance of individual athletes. Commentswill also be made on the place of maximaloxygen intake assessment in various areasof science, sports medicine and clinicalmedicine.

IS THE MAXIMAL TREADMILL TEST AN

UNREALISTIC PROCEDURE FORATHLETES?Noakes argues1 that the treadmill test isan unrealistic approach to the testing of athletes for three reasons: the duration of the exercise is not known to the subject,there is a steep and progressive increase inthe intensity of exercise, and the personwho is tested has no control over theultimate intensity of effort. All of thesecriticisms may be true of the test protocolused in some laboratories. However, thestandard recommendation is for a tread-

mill test lasting 9–11 minutes, and thisshould be explained to the subject. Theappropriate treadmill slope and speedshould be ascertained by preliminary submaximal testing; this allows the defi-nitive test to commence close to maximalsteady-state effort, thereby avoiding asteep ramp of intensity. Moreover, themaximal value can be determined by carrying out a series of tests on successivedays, although the values obtained in thismanner do not differ materially from thoseseen with an appropriately conductedcontinuous test protocol.2 Finally, proto-

cols are available that allow the subject toregulate the speed of the treadmill himself or herself as the test proceeds.

There are thus ways of dealing with theproblems cited by Noakes. However, thereremain some important differencesbetween a laboratory treadmill test andathletic performance that Noakes doesnot discuss. Most treadmills cannotmatch the speed of short-distance run-ners. While on a treadmill, an athlete doesnot encounter wind resistance3 and can-not profit from ‘‘drafting’’.4 Few labora-

tories simulate radiant heating or coolingby cross-winds, and the running surfaceof the treadmill differs substantially fromthe usual track. However, these variouslimitations apply only to laboratory mea-surements, and do not negate the value of maximal oxygen intake testing, since it isquite practicable to measure oxygen con-sumption when an athlete is running on astandard track.5

Other factors affecting athletic perfor-mance include an appropriate choice of tactics (including selection of clothing),motivation of the individual, and the

mechanical efficiency of movement. Nolaboratory test seems likely to evaluate

tactical skills. The motivating power of the observer is important to the reachingof an oxygen consumption ‘‘plateau’’, andlaboratories that have difficulty indemonstrating this phenomenon6 prob-ably need to upgrade their motivationalskills. Mechanical efficiency can be esti-mated roughly from treadmill data,

although other forms of ergometer pro-vide more precise values.7

IS A UNIMODAL APPROACH TO TESTINGAPPROPRIATE?

Another puzzling feature of the recentreview1 is the apparent assumption thateveryone will be tested on a treadmill. TheInternational Working Party that standar-dised procedures for the measurement of maximal oxygen intake suggested thatthree possible modes of testing were suita-ble for ordinary, non-athletic individuals,

based on a treadmill, a double step and acycle ergometer.8 In non-athletic indivi-duals, the largest values were obtained onthe treadmill; step test readings were onaverage 4 per cent smaller, and cycleergometer values 7 per cent smaller.

Intermodal differences in maximal oxy-gen intake are thought to reflect thediffering proportions of the total musclemass that are used in the differentprotocols9; intermodal differences aremuch larger in athletes who have trainedone particular group of muscles. Forathletes, it is thus critical to select a testmodality that allows use of the musclesengaged in their chosen sport; for acyclist, the natural choice would be acycle ergometer or a racing bicyclemounted on rollers,10 for the oarspersona rowing ergometer or the collection of gas samples during actual rowing,11 for thecross-country skier a skiing ergometer oruphill skiing,12 and for the swimmer aflume or the collection of gas samplesduring swimming in a pool.13 14 Plainly, formany categories of athlete, the treadmillis an inappropriate test modality.

CAN LABORATORY TESTS OFFER AUSEFUL PREDICTION OF ATHLETICABILITY?

Given the various constraints notedabove, it seems unlikely that any labora-tory test can be devised that will categor-ise athletes of similar ability with usefulaccuracy. Rather, athletes should beranked based on the actual performancesachieved over several recent competitions.Here, tactics, motivation and mechanicalefficiency all come into play, and the

mode of exercise is entirely natural.Moreover, individual performances can

be determined to a small fraction of asecond. This compares very favourably with the laboratory treadmill, since evencareful determinations of maximal oxy-gen intake have an experimental error of 2–4 per cent, and superimposed upon thisis an intraindividual biological variation of 10–20 per cent.15

WHAT ARE APPROPRIATE USES OFMAXIMAL OXYGEN INTAKEDETERMINATION?Maximal oxygen intake tests are of littlehelp in ranking athletes of similar ability.However, this does not imply that suchmeasurements are passe. On the contrary,the testing of maximal oxygen intake hasmany appropriate and important applica-tions. This concluding section highlightsjust a few such applications, in integrativebiology, sports medicine, doping control,

epidemiology and clinical medicine.

Integrative biology Analysis of the oxygen conductance equa-tion under conditions of maximal aerobiceffort16 provides helpful insights into thefactors limiting various types of physicalperformance.9 In activities that involvelarge muscle groups, oxygen transport isdetermined almost entirely by maximalcardiac output, and, taken together withdeterminations of heart rate, the measure-ment of maximal oxygen intake offers a

useful method of examining cardiacstroke volume during maximal aerobicexercise. If the external work is measured,the mechanical efficiency of various typesof activity can also be determined.7

Sports medicineGrouped data on the maximal oxygenintake of top competitors provide insightsinto the extent of aerobic demands invarious forms of sport.17 Comparisons of the grouped physiological profile with theindividual’s personal data may suggesthow large an emphasis the individual

should place upon enhancing his or heraerobic power. Careful records of anindividual’s maximal oxygen intake arealso helpful in evaluating the extent of any deterioration in aerobic functionfollowing injury or overtraining, and inmonitoring the recovery of aerobic func-tion following such episodes.18

Doping control A variety of drugs19 and manipulations suchas blood transfusions20 can induce smallincrements of maximal oxygen intake

that have an important influence on theoutcome of endurance competitions.

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84 Br J Sports Med February 2009 Vol 43 No 2



Measurements of maximal oxygen intakeunder carefully controlled double-blindtrials are thus important in distinguishingmedications that are acceptable (forinstance, certain drugs used in the treat-ment of bronchospasm induced by exerciseor cold) from those which would giveathletes an unfair advantage.

Epidemiology It is widely agreed that the majority of the population in developed countriescurrently takes insufficient physical activ-ity, with adverse consequences for many facets of health.21 Nevertheless, the deter-mination of the physical activity of apopulation, whether by questionnaire orby use of accelerometers, is unreliable, andthe mass testing of maximal oxygenintake provides a helpful alternativeapproach when assessing the extent of

endurance activity within a population.

2

Maximal oxygen intake data can also beused to demonstrate secular trends inhabitual physical activity; for instance,repeated measurements in a Canadiancircumpolar community have shown aprogressive decrease of maximal oxygenintake as the community has adopted thesedentary lifestyle typical of their peers insouthern Canada.22

Clinical medicineIn many clinical situations, the oxygenintake is limited by warning symptoms or

signs before a ‘‘plateau’’ is reached. Thevalue thus reported is termed the peakrather than the maximal oxygen intake.The peak aerobic power provides a usefulindication of prognosis in patients withvarious types of cardiac disorder.23 Such

observations also provide an optimal basisfor the setting of a safe and effectiveintensity of training in programmes of cardiac rehabilitation.24 Clinical informa-tion can be derived from the extent of STdepression at various fractions of anindividual’s maximal oxygen intake.25

Finally, determinations of maximal oxy-

gen intake are helpful in gauging recovery following bed rest, injury, and exposure tozero gravity environments.

Competing interests: None.

Accepted 7 August 2008Published Online First 21 August 2008

Br J Sports Med 2009;43:83–85.doi:10.1136/bjsm.2008.052506

REFERENCES1. Noakes TD. Testing for maximum oxygen

consumption has produced a brainless model ofhuman exercise performance. Br J Sports Med

2008;42:551–5.2. Shephard RJ. Aerobic fitness and health.Champaign, IL: Human Kinetics, 1994.

3. Pugh LGCE. The influence of wind resistance inrunning and walking and the mechanical efficiency ofwork against horizontal or vertical forces. J Physiol 1970;213:255–76.

4. Yamaji K, Shephard RJ. Grouping of runners duringmarathon competition. Br J Sports Med 1987;21:1661–7.

5. McMiken DF, Daniels JT. Aerobic requirements andmaximum aerobic power in treadmill and trackrunning. Med Sci Sports Exerc 1976;8:14–17.

6. Noakes TD. How did AV Hill understand the VO2maxand the ‘‘plateau phenomenon’’? Still no clarity?

Br J Sports Med 2008;42:574–80.7. Shephard RJ. Physiology and Biochemistry of

Exercise. New York, NY: Praeger Publications, 1982.8. Shephard RJ, Allen C, Benade AJS, et al . Themaximum oxygen intake- an international referencestandard of cardio-respiratory fitness. Bull World

Health Org 1968;38:757–64.9. Shephard RJ, Bouhlel E, Vandewalle H, et al . Muscle

mass as a factor limiting physical work. J Appl Physiol 1988;64:1472–9.

10. Hagberg J, McCole S. Energy expenditure duringcycling. In: Burke ER, ed. High Tech Cycling.Champaign, IL: Human Kinetics, 1996:167–84.

11. Jackson RC, Secher NH. The aerobic demands ofrowing in two Olympic rowers. Med Sci Sports Exerc1976;8:168–70.

12. Stromme SB, Inger F, Meen HD. Assessment ofmaximal aerobic power in specifically trained athletes.

J Appl Physiol 1977;42:833–7.13. Holmer I. Physiology of swimming man. Ex Sport Sci

Rev 1979;7:87–123.14. Pendergast DR, Di Prampero PE, Craig AB, et al . Theinfluence of biomechanical factors on the energy costof swimming. In: Eriksson B, Fu rberg B, eds.Swimming Medicine IV . Baltimore, MD: UniversityPark Press, 1978.

15. Wright GR, Sidney KH, Shephard RJ. Variance ofdirect and indirect measurements of aerobic power.

J Sports Med Phys Fitness 1978;18:33–42.16. Shephard RJ. The oxygen conductance equation. In:

Shephard RJ, ed. Frontiers of fitness. Springfield, IL:C.C. Thomas, 1971:129–164.

17. Shephard RJ, Astrand P-O. Endurance in Sport . 2nded. Oxford, UK: Blackwell Science, 2000.

18. Jeukendrup AE, Hesselink MKC, Snyder AC, et al .Physiological changes in male competitive cyclistsafter two weeks of intensified training. Int J Sports

Med 1992;

13:534–41.

19. Williams MH. Smoking, alcohol, ergogenic aids andthe endurance performer. In: Shephard RJ, Astrand P-O, eds. Endurance in Sport . 2nd ed. Oxford, UK:Blackwell Science, 2000:438–50.

20. Gledhill N, Warburton D. Hemoglobin, blood volumeand endurance. In: Shephard RJ, Astrand P-O, eds.

Endurance in Sport . 2nd ed. Oxford, UK: BlackwellScience, 2000:423–37.

21. Bouchard C, Shephard RJ, Stephens T. Physical activity, fitness and health. Champaign, IL: HumanKinetics, 1994.

22. Shephard RJ, Rode A. The health consequences of‘modernization.’ Evidence from circumpolar peoples.London, UK: Cambridge University Press, 1996.

23. Kavanagh T, Hamm LF, Beyene J, et al . Usefulnessof improvement in walking distance versus peakoxygen uptake in predicting prognosis aftermyocardial infarction and/or coronary artery bypassgrafting in men. Am J Cardiol 2008;101:1423–7.

24. Shephard RJ, Miller HS. Exercise and the Heart in Health and Disease. 2nd ed. New York, NY: MarcelDekker, 1999.

25. Shephard RJ. Ischemic heart Disease and Exercise.London, UK: Croom Helm, 1981.

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is the measurement of maximal oxygen intake passe

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