Maximal Accumulated Oxygen Deficit Research Articles

Maximal accumulated oxygen deficit must be calculated using 10-min time periods.

The accumulated O2, calculated by an extrapolation procedure from measurements of the O2 uptake at moderate powers, has been suggested as a measure of the anaerobic energy release during high intensity exercise. While some suggest that repeated 10-min bouts are required to establish the relationships in question, other use bouts of shorter durations. The purpose of this study was to examine how different exercise durations influence the calculated accumulated O2 deficit. Eight endurance trained male cyclists with the following characteristics (Mean +/- SE): age, 25 +/- 3 yr; weight, 69.9 +/- 1.7 kg: height, 178.2 +/- 1.0 cm; and VO2max 57.5 +/- 2.4 mL x kg(-1) x min(-1) volunteered for participation in this study. The O2 uptake was measured at 2-4, 4-6, 6-8, and 8-10 min of exercise at ten different constant powers. These O2 uptakes were used to establish four relationships between the power and O2 demand for each subject. On a separate day the subjects cycled at a power of 336 +/- 42 W (corresponding to about 110% of the maximal O2 uptake) for 296 +/- 43 s to exhaustion while the O2 uptake was measured continuously. For each subject the accumulated O2 deficit was determined from the different relationships. The accumulated O2 deficit determined from the relationships from the 2 to 4-min exercises in the pretests were significantly less than the value calculated from the relationships obtained after the 8-10 min of exercise at constant power, the values being 39.6 +/- 11.6 mL O2 eq x kg(-1) and 53.4 +/- 14.6 mL O2 eq x kg(-1), respectively. This study suggests that reducing the exercise duration used in the pretests to establish the relationships between power and O2 demand from 10 min may lead to a too low accumulated O2 deficit.

Exercise that induces substantial muscle glycogen depletion impairs subsequent anaerobic capacity.

The purpose of this study was to develop a model of muscle glycogen depletion and to study the effect of this model on aerobic and anaerobic capacity of horses. The maximal rate of oxygen consumption (VO2max), maximal accumulated oxygen deficit (MAOD), muscle glycogen concentration and blood lactate concentration of 6 fit Standardbred horses were measured on 3 occasions 7 days apart (Trials 1, 2 and 3). Between Trials 2 and 3, strenuous exercise intended to deplete muscle glycogen was performed by exercising horses on the treadmill on 3 consecutive days. Strenuous exercise resulted in reduction of muscle glycogen concentration by at least 55% (from mean +/- s.e. 155.1 +/- 5.6 mmol/kg, wet weight, before Trial 2 to 55.4 +/- 5.5 mmol/kg before Trial 3; P < 0.05). VO2max was similar in Trials 2 and 3 (140.4 +/- 5.4 ml O2/kg bwt and 141.8 ml +/- 6.2 ml O2/kg, respectively). Run time to fatigue during a single high-speed exercise test (253.9 +/- 33.3 s and 153.8 +/- 16.4 s, P < 0.05), accumulated oxygen deficit (95 +/- 13.2 ml O2/kg and 35 +/- 13.9 ml O2/kg, P < 0.05) and blood lactate concentration at the end of the sprint (17 +/- 1.2 mmol/l and 10.5 +/- 1.1 mmol/l, P < 0.05) were less during Trial 3 than Trial 2. These data suggested that repeated strenuous exercise that causes muscle glycogen depletion results in impairment of anaerobic, but not aerobic, metabolism.

Influence of Time of Day on Anaerobic Capacity

12 volunteers performed exhaustive exercise tests in the morning and afternoon. Paired-means t tests indicated that anaerobic capacity, as reflected by maximal accumulated oxygen deficit, was 26% higher (p < .01) in the afternoon than in the morning. VO2max appeared higher and VO2 kinetics seemed faster in the afternoon, but differences did not attain statistical significance. Thus, the time of day affects anaerobic capacity and may influence other responses to exercise.

Metabolic profile of high intensity intermittent exercises.

To evaluate the magnitude of the stress on the aerobic and the anaerobic energy release systems during high intensity bicycle training, two commonly used protocols (IE1 and IE2) were examined during bicycling. IE1 consisted of one set of 6-7 bouts of 20-s exercise at an intensity of approximately 170% of the subject's maximal oxygen uptake (VO2max) with a 10-s rest between each bout. IE2 involved one set of 4-5 bouts of 30-s exercise at an intensity of approximately 200% of the subject's VO2max and a 2-min rest between each bout. The accumulated oxygen deficit of IE1 (69 +/- 8 ml.kg-1, mean +/- SD) was significantly higher than that of IE2 (46 +/- 12 ml.kg-1, N = 9, p < 0.01). The accumulated oxygen deficit of IE1 was not significantly different from the maximal accumulated oxygen deficit (the anaerobic capacity) of the subjects (69 +/- 10 ml.kg-1), whereas the corresponding value for IE2 was less than the subjects' maximal accumulated oxygen deficit (P < 0.01). The peak oxygen uptake during the last 10 s of the IE1 (55 +/- 6 ml.kg-1.min-1) was not significantly less than the VO2max of the subjects (57 +/- 6 ml.kg-1.min-1). The peak oxygen uptake during the last 10 s of IE2 (47 +/- 8 ml.kg-1.min-1) was lower than the VO2max (P < 0.01). In conclusion, this study showed that intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally.

Effect of muscle glycogen availability on maximal exercise performance.

This investigation determined the influence of pre-exercise muscle glycogen availability on performance during high intensity exercise. Nine trained male cyclists were studied during 75 s of all-out exercise on an air-braked cycle ergometer following muscle glycogen-lowering exercise and consumption of diets (energy content approximately 14 MJ) that were either high (HCHO(80% CHO) or low (LCHO-25% CHO) in carbohydrate content. The exercise-diet regimen was successful in producing differences in pre-exercise muscle glycogen contents [HCHO: 578(SEM 55) mmol x kg(-1) dry mass; LCHO: 364 (SEM 58) P < 0.05 mmol x kg(-1) dry mass]. Despite this difference in muscle glycogen availability, there were no between trial differences for peak power [HCHO 1185 (SEM 50)W, LCHO 1179 (SEM 48)W], mean power [HCHO 547 (SEM 5)W, LCHO 554 (SEM 8)W] and maximal accumulated oxygen deficit [HCHO 54.4 (SEM 2.3) ml x kg(-1), LCHO 54.6 (SEM 2.0) ml x kg(-1)]. Postexercise muscle lactate contents (HCHO 95.9 (SEM 4.6) mmol x kg(-1) dry mass, LCHO 82.7 (SEM 12.3) mmol x kg(-1) dry mass, n = 8] were no different between the two trials, nor were venous blood lactate concentrations immediately after and during recovery from exercise. These results would indicate that increased muscle glycogen availability has no direct effect on performance during all-out high intensity exercise.

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P < 0.01) (mean +/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d.wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Is the maximal accumulated oxygen deficit an adequate measure of the anaerobic capacity?

If these three assumptions are justified, the accumulated 0, deficit is an ac-curute or unbiased measure of the anaerobic energy released during exercise. All measurements used to calculate the accumulated 0, deficit are subject to random errors and are thus more or less imprecise. The main purpose of this paper is to discuss possible limitations in the accumulated 0, deficit as a measure of the anaerobic energy release during exercise and how the anaerobic capacity may be found.

MAXIMAL ACCUMULATED OXYGEN DEFICIT OF RESISTANCE TRAINED MEN 404

The primary purpose of the study was to compare maximal accumulated oxygen deficit (MAOD) in resistance trained (RT, N=11), endurance trained (ET, N=10) and untrained men (UT, N=12). A secondary purpose was to determine the influence of leg muscle mass (MM) on MAOD by examining the relationship between MM and MAOD and by comparing MAOD expressed relative to MM between the groups. MAOD was determined during 2-4 min of constant-load fatiguing cycling. Leg muscle mass was estimated via anthropometric measurements(Mean±SE). Table # significant (p<0.05) difference compared to UT and ET, * significant difference compared to UT. A significant positive correlation was observed between MAOD (l O2 eq) and MM (kg) for RT only (RT r=0.85, ET r=0.55, UT r=0.20). Based on the correlational and mean MM data, the higher MAOD (l O2 eq) in RT relative to ET and UT is predominantly the result of their larger leg muscle mass. The mean data for the relative expression of MAOD (ml O2 eq·kg-1 MM) suggest that there are also anaerobic metabolic adaptations that may contribute to the higher MAOD in RT and ET compared to UT.

Anaerobic capacity and maximal oxygen uptake during arm stroke, leg kicking and whole body swimming.

In the present study, we determined both anaerobic capacity (the maximal accumulated oxygen deficit) and maximal oxygen uptake (VO2max) during arm stroke (A), leg kicking (K), and whole body swimming (S), and compared them. The subjects were six trained college swimmers (two male and four female), aged 20 +/- 1 years. To determine VO2max for A, K and S, VO2max was measured during a 6-min swim at constant water flow rates. VO2 was measured by the Douglas bag method. Anaerobic capacity was determined by accumulated oxygen deficit during exercise lasting 2-3 min according to the methods of Medbø et al. Mean values of VO2max during A, K and S were 2.53 +/- 0.37 L min-1, 2.93 +/- 0.37 L min-1, and 3.23 +/- 0.43 L min-1, respectively. Those in A and K corresponded to 78.2% and 91.0% of that in S. Mean values of anaerobic capacity during A, K and S were 2.15 +/- 0.31 L, 2.52 +/- 1.08 L and 2.99 +/- 0.52 L, respectively. Those in A and K corresponded to 73.3% and 81.7% of that in S. Both VO2max and anaerobic capacity in S were much lower than the sum of A and K, corresponding to only 59.3% and 65.9%, respectively. These results suggest that the total energy production during S is lower than simply the sum of A and K because the potentials of both the anaerobic and aerobic energy releasing processes in the muscle groups involved in A and K cannot be fully reached during S.

Effect of a warm-up on energy supply during high intensity exercise in horses.

The VO2(max) in racehorses is approximately double that of elite human athletes and the rate of increase in VO2 at the onset of high intensity exercise is much greater than in man. The kinetics of gas exchange are affected by a warm-up prior to exercise in humans, there being a greater aerobic contribution to high intensity exercise after warm-up. Our hypothesis was that a warm-up would increase aerobic energy delivery in racehorses during high intensity exercise. Thirteen fit Standardbred racehorses ran to fatigue at 115% of VO2(max) on a treadmill at 10% slope. Prior to acceleration, horses were exercised either for 5 min at 50% VO2(max) followed by 5 min walk, or walked for 2 min. Samples of expired gas were collected every 10 s during the run for determination of VO2 and VCO2 and measurement of maximal accumulated oxygen deficit (MAOD). Blood lactate concentration was measured 5 min post exercise. We found that with a warm-up, horses had faster kinetics of gas exchange and a greater proportion of their total energy requirement was supplied by aerobic sources. The aerobic contribution to total energy requirement with and without warm-up was, respectively, 79.3 +/- 1.0% and 72.4 +/- 1.7% (P < 0.01). There was also a higher MAOD (P < 0.01) in horses that had not been given a warm-up (mean +/- s.e.m. 34.7 +/- 2.6 and 47.3 +/- 2.6 mLO2eq/kg bwt with and without a warm-up respectively). However, there were no significant differences in total run time or estimated total energy expenditure between the 2 protocols. We concluded that during high intensity exercise to fatigue lasting 1 to 2 min, more than 70% of energy supply is from aerobic energy sources and that this contribution is even greater when the horses have received a warm-up.

Anaerobic Capacity: A Maximal Anaerobic Running Test Versus the Maximal Accumulated Oxygen Deficit

The present investigation evaluates a maximal anaerobic running test (MART) against the maximal accumulated oxygen deficit (MAOD) for the determination of anaerobic capacity. Essentially, this involved comparing 18 male students performing two randomly assigned supramaximal runs to exhaustion on separate days. Post warm-up and 1, 3, and 6 min postexercise capillary blood samples were taken during both tests for plasma blood lactate (BLa) determination. In the MART only, blood ammonia (BNH3) concentration was measured, while capillary blood samples were additionally taken after every second sprint for BLa determination. Anaerobic capacity, measured as oxygen equivalents in the MART protocol, averaged 112.2 +/- 5.2 ml.kg-1.min-1. Oxygen deficit, representing the anaerobic capacity in the MAOD test, was an average of 74.6 +/- 7.3 ml.kg-1. There was a significant correlation between the MART and MAOD (r = .83, p < .001). BLa values obtained over time in the two tests showed no significant difference, nor was there any difference in the peak BLa recorded. Peak BNH3 concentration recorded was significantly increased from resting levels at exhaustion during the MART.

A macro-driven Excel template for determining the anaerobic capacity using an air-braked ergometer.

This paper describes a microcomputer system for automating the process of data collection, calculation and display of anaerobic capacity tests on an air-braked ergometer. The use of the spreadsheet Excel and associated 'Dalog' program represents an advance on current software which estimates the anaerobic capacity from work performed alone. Numerous calculations are required when air-braked, rather than friction-braked erogometers are used. Each 1 s power output collected during an all-out sprint on the ergometer is corrected against the criterion of a dynamic calibration rig and adjusted for differences in barometric pressure, ambient temperature and humidity. The Excel template features a series of macros invoked by buttons imbedded in the spreadsheet. Their selection displays various dialogue boxes which request input related to the calculation of oxygen deficit and related variables. Selecting the final macro prints a summary table and charts which include: power output, fatigue index, mechanical work performed, % aerobic contribution to work, oxygen demand, oxygen consumption and anaerobic capacity as determined by the maximal accumulated oxygen deficit.

Influence of test duration and event specificity on maximal accumulated oxygen deficit of high performance track cyclists.

This study examined the relationship between the time required to fully utilise the maximal accumulated oxygen deficit (MAOD) and event specificity of track cyclists. Twelve track endurance and 6 sprint high performance track cyclists performed four treatments of 70 s, 120 s, 300 s and 115% VO2max of maximal cycling on an air-braked ergometer. Peak blood lactate was measured immediately after each test with VO2 kinetics being assessed during the 115% VO2max time to exhaustion test. When the two cycling groups were combined there was no significant difference in the MAOD when assessed under the four different exercise durations. However, when the groups were analysed separately the following results were apparent: (1) the sprint cyclists achieved a significantly greater MAOD (66.9 +/- 2.2 ml.kg-1) compared to the track endurance cyclists (57.6 +/- 6.7 ml.kg-1) when a 70 s test duration was employed (2) even though the track endurance cyclists achieved their greatest MAOD during the 300 s test protocol (62.1 +/- 11.0 ml.kg-1), it was not significantly different to the MAOD's measured during the three other test durations and (3) the sprint cyclists recorded their greatest MAOD during the 70 s supramaximal test protocol (66.9 +/- 2.2 ml.kg-1). This was not significantly different to the 120 s test MAOD, but it was significantly higher than the MAOD values recorded during the 115% VO2max and 300 s test durations. There was no significant difference between the two groups in the peak post-exercise blood lactate concentrations for any of the tests and only the 70 s test produced a significant correlation between peak blood lactate and the MAOD. The VO2 kinetics (VO2 t1/2) of the sprinters was significantly slower than that of the track endurance cyclists (26.3 +/- 2.3 vs 23.9 +/- 2.8 s.). The findings of this study demonstrate that sprint cyclists can fully express their anaerobic capacity within an event specific 70 s all-out test and that these cyclists progressively decrease their anaerobic capacity during a 120 s, 115% VO2max (mean time = 210 s) or 300 s test, despite giving all-out efforts. Conversely, track endurance cyclists achieve their highest mean score during an event specific 300 s test and their lowest during a 70 s test. These findings have important implications when testing high performance cyclists for determination of MAOD, with the implication that it is necessary to assess MAOD under exercise conditions (i.e., duration, pacing) specific to the cyclist's chosen event.

Effect of a diet containing supplementary fat on the capacity for high intensity exercise

SummaryThis study investigated the effects of increased fat consumption on aerobic and anaerobic performance. Eight Thoroughbred horses that had undergone a 9 week, 6 days/week conditioning programme were randomly divided into 2 groups,Group F(5 horses) andGroup C(3 horses). For 2 weeks before the study all horses consumed a standard diet (2% fat) fed as 2 equal portions. Horses then undertook an incremental treadmill exercise test (+10% slope); 3 min at 4 m/s, 2 min at 6 m/s and 1 min at 8 m/s. Speed was then increased by 1 m/s every 60 s until fatigue. Maximal accumulated oxygen deficit (MAOD) was determined 72 h later. Horses inGroup Fwere then fed a diet containing 12% of the digestible energy in the form of fat (390 ml corn oil), a diet that was isocaloric with the control diet. Horses inGroup Ccontinued to receive the standard diet. All horses continued training (3600 m/day, at speeds up to 10 m/s, 6 days/week). After 4 weeks, the exercise tests were repeated. Prior to fat supplementation, V̄O2maxwas mean ± s.e. 145 ± 5.3 and 148.0 ± 6.0 ml/kg/min, time to fatigue during the MAOD test was mean ± s.e. 84.2 ± 18.4 and 85.0 ± 14.8 s, mean ± s.e. peak plasma [lactate] was 24.8 ± 3.1 and 23.5 ± 1.7 5 mmol/l and MAOD was 56.5 ± 5.3 and 68.1 ± 4.7 mlO2eq/kg forGroups FandCrespectively. The V̄O2maxand run time to fatigue in the incremental exercise test did not change in either group following fat supplementation. Run time (mean ± s.e. 97.2 ± 17.8 s), MAOD (65.5 ± 6.2 mlO2eq/kg) and peak plasma [lactate] (29.5 ± 2.6 mmol/l) increased during the MAOD test inGroup Fbut remained unchanged inGroup C.Resting muscle [glycogen] depletion during the MAOD test was not altered by the dietary manipulation. Provision of an increased proportion of the diet in the form of fat increased high intensity exercise capacity and the MAOD during intense treadmill exercise.

Assessment of anaerobic capacity using maximal accumulated oxygen deficit in fit Thoroughbreds

SummaryTwenty‐three Thoroughbred racehorses that were presented for a standard incremental exercise test also performed a test at an intensity equivalent to 115% V̇O2max in an effort to evaluate their anaerobic capacity by measuring the maximal accumulated oxygen deficit (MAOD). Submaximal V̇O2 values for speeds 3 to 10 m/s and V̇O2max were determined for horses exercising on a treadmill inclined at a 10% slope. An individual regression equation of speed and V̇O2 was used to calculate the speed for each horse to exercise at 115% V̇O2max and the energy demand for exercise at this intensity. The horses underwent a warm‐up period consisting of 5 min at 50% V̇O2max followed by walking for 5 min at 1.5 m/s. The treadmill was then acclerated as rapidly as possible until a speed of 115% V̇O2max was attained. During the test, expired gas samples were collected at 0, 15, 30, 45, 60 s and every 30 s until fatigue. MAOD was calculated by subtracting the measured oxygen uptake from the calculated oxygen demand. A 5 min post exercise blood sample was collected for measurement of plasma [lactate]. The MAOD values ranged from 36 to 94 mlO2 equivalents/kg and the V̇O2max values ranged from 128 to 170 ml/kg/min. The mean ± s.e. MAOD values were 59 ± 3 mlO2 equivalents/kg and mean V̇O2max was 146 ± 2 ml/kg/min. Mean plasma [lactate] was 23.0 ± 1.2 mmol/l. MAOD was weakly correlated with V̇O2max (r = 0.514, P &lt; 0.05), but was not correlated with run time, plasma lactate or treadmill work. The test of MAOD was suitable for use during clinical exercise testing.

Three day eventing: thermoregulatory considerations

require estimation of maximal values from submaximal measurements, introducing an added error into calculations. Variables such as Vlso and Vlg0 are considered inadequate due to the variability in heart rates at low exercise intensities. Some workers are now relating submaximal to maximal values, such as V2#HRmaX, HRI&Rma, and Lal&amax. This increases the accuracy over the submaximal value alone, but it does necessitate the use of a maximal exercise test. To date, most tests have examined aerobic capacity because anaerobic capacity is more difficult to measure. The measurements of maximum accumulated oxygen deficit (MAOD), presented by Eaton et al. (1995) may provide an indication of anaerobic capacity. However, this measurement requires a rapid acceleration, maximal speed treadmill run.

Maximal accumulated oxygen deficit in thoroughbred horses.

Thoroughbred horses have a high aerobic capacity, approximately twice that of elite human athletes. Whereas the aerobic capacity of horses can be accurately measured, there have been no measurements of anaerobic capacity. The aim of this study was to determine whether maximal accumulated O2 deficit (MAOD) could be measured in horses and used as an estimate of anaerobic capacity, as in human athletes. Six fit Thoroughbred horses were used with the exercise protocol utilizing a treadmill set at a 10% incline. O2 uptake VO2 was measured via an open-flow system for seven submaximal speeds (3-9 m/s), and maximal VO2 (135 +/- 3 ml.kg-1.min-1) was determined. The horses performed three tests at 105 and 125% and six tests at 115% of maximal VO2. The MAOD test was performed with the treadmill accelerated rapidly from 1.5 m/s (mean acceleration time 8 s) to the calculated speed (11-14 m/s). VO2 was measured every 10 or 15 s, and the test ended when the horse no longer kept pace with the treadmill. The mean run times were 165, 98, and 57 s for intensities of 105, 115, and 125% maximal VO2. The mean MAOD values were 31 +/- 2, 30 +/- 1, and 32 +/- 2 (SE) ml O2 eq/kg for the three intensities (P > 0.05). The proportion of energy derived from aerobic and anaerobic sources was calculated from the difference between calculated O2 demand and the VO2 curve. There was no correlation between MAOD and maximal VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Accumulated oxygen deficit during supramaximal all-out and constant intensity exercise

Two studies were conducted to test the validity of an all-out procedure for the assessment of the maximal accumulated oxygen deficit (AOD). Subjects in study 1 (N = 9; VO2max = 57 +/- 3 ml.kg-1.min-1 [+/- SEM]) completed three supramaximal efforts on a cycle ergometer. Exhaustive exercise during an all-out isokinetic procedure (mean intensity of 149% VO2max) was compared with constant intensity exercise at approximately 110% and 125% VO2max. Subjects in study 2 (N = 12; VO2max = 55 +/- 3 ml.kg-1.min-1) completed a constant intensity test to exhaustion at approximately 110% VO2max and a 90 s all-out test on a Monark friction loaded cycle ergometer (mean intensity of 143% VO2max). The AOD within each study were not significantly different (study 1:43.9, 44.1, and 42.0 ml.kg-1 for the 110%, 125%, and all-out tests; study 2: 52.1 and 51.2 ml.kg-1 for the 110% and all-out tests, respectively; P > 0.05). The total amount of work was significantly greater the longer the test, the additional work being attributed to aerobic processes. The rate of both aerobic and anaerobic energy production in the first 30 s of exercise was directly related to exercise intensity and the protocol used. The results indicate that an all-out procedure provides a valid estimate of the maximal AOD and shows potential for a more complete assessment of anaerobic ability as traditional indices of high intensity exercise performance are also obtained.

Quantification of anaerobic capacity

Anaerobic capacity may be defined as the maximal amount of ATP formed by the anaerobic processes during a single bout of maximal exercise. While several methods have been presented to measure a person's anaerobic capacity, none have become universally accepted. The muscle biopsy technique provides information on the anaerobic energy release from direct measures of ATP and CP breakdown and muscle lactate concentrations. As a practical measure of anaerobic capacity, the method may be limited, as it is an invasive, skilled technique. Furthermore, it has the limitation of measuring relative changes in concentrations, not amounts, such that the anaerobic contribution is estimated from estimates of the active muscle mass involvement. Measurement of lactate in blood after exhaustive exercise has frequently been used, but several factors suggest that, while it provides an indication of the extent of anaerobic glycolysis, it cannot be used as a quantitative measure of the anaerobic energy yield. The mean power during an all‐out effort on a bicycle ergometer has also been assumed to be a measure of anaerobic capacity, yet it provides only an indication of the ability to maintain high power outputs. Concerns over the duration of the test, the protocol and type of ergometer used and the contribution of the aerobic energy system to the energy supply also limit its validity as a measure of anaerobic capacity. The oxygen debt, defined as the recovery oxygen uptake above resting metabolic rates, has been discredited as a valid and reliable measure of the anaerobic capacity, as it is generally acknowledged that mechanisms other than the metabolism of lactate also contribute to the post‐exercise oxygen uptake. The recent work of Medbø et al. in re‐examining the issue of oxygen deficit has created considerable interest in its use as a measure of anaerobic capacity. The measurement of oxygen deficit directly depends on the accurate assessment of the energy cost of the work completed. This is not difficult during submaximal exercise, as the steady‐state oxygen uptake represents the energy costs. During exhaustive supramaximal exercise, the validity of the maximal accumulated oxygen deficit as a measure of the anaerobic capacity has been questioned, as the energy cost is estimated and not measured, either by assuming a given mechanical efficiency or by extrapolating the submaximal relationship between work intensity and oxygen uptake to supramaximal levels. Despite these theoretical objections, the maximal accumuiated oxygen deficit method remains a promising measure of the anaerobic capacity, as it provides a non‐invasive means of quantifying the anaerobic energy release during exhaustive exercise.

Anaerobic Capacity in Humans: Validation of a Maximal Anaerobic Running Test against the Maximal Accumulated Oxygen Deficit

Anaerobic Capacity in Humans: Validation of a Maximal Anaerobic Running Test against the Maximal Accumulated Oxygen Deficit