Maximal Accumulated Oxygen Deficit Research Articles

The effect of pedalling cadence on maximal accumulated oxygen deficit

Pedalling cadence influences the oxygen demand and the tolerable duration of severe intensity cycle ergometer exercise. Both of these variables are factors in the calculation of maximal accumulated oxygen deficit (MAOD), which is a widely accepted measure of anaerobic capacity. We were therefore interested in determining whether pedalling cadence affected the value of MAOD. Eighteen university students performed square wave cycling tests, using cadences of 60, 80, and 100 rev min(-1), at work rates selected to cause exhaustion in ~5 min. The oxygen demands for the tests were estimated by extrapolation from the steady-state oxygen uptake in two 4-min moderate intensity bouts performed using each cadence, and were greater at higher cadences. Times to exhaustion were shorter at higher cadences (368 ± 168 s at 60 rev min(-1) > 299 ± 118 s at 80 rev min(-1) > 220 ± 85 s at 100 rev min(-1)). These factors conflated to produce values for MAOD that were not affected by cadence (52 ± 5 ml kg(-1) = 52 ± 5 ml kg(-1) = 52 ± 5 ml kg(-1)). Similarly, the blood lactate concentrations measured 5 min post-exercise were not affected by the pedalling cadence (10.5 ± 2.1 mM = 10.8 ± 1.0 mM = 10.7 ± 2.0 mM). Although muscle contraction frequency influences many exercise responses, we conclude that the expression of anaerobic capacity is not affected by the choice of pedalling cadence.

Maximal accumulated oxygen deficit in running and cycling

The purpose of this study was to compare values of maximal accumulated oxygen deficit (MAOD; a measure of anaerobic capacity) in running and cycling. Twenty-seven women and 25 men performed exhaustive treadmill and cycle ergometer tests of ∼3 min, ∼5 min, and ∼7 min duration. Oxygen demands were estimated assuming a linear relationship between demand and intensity and also using upwardly curvilinear relationships. When oxygen demand was estimated using speed (with exponent 1.05), values for MAOD for the three running tests were virtually identical; the mean of the three values was 78 ± 7 mL·kg⁻¹. Use of an oxygen demand that was estimated using work rate (with exponent 1.00) generated the most similar values for MAOD from the three cycling tests (mean of 59 ± 6 mL·kg⁻¹). Consistent with the higher (p < 0.05) MAOD in running, peak post-exercise blood lactate concentrations were also higher (p < 0.05) in running (13.9 ± 2.2 mmol·L⁻¹) than in cycling (12.6 ± 2.4 mmol·L⁻¹). The results suggest that the relationship between oxygen demand and running speed is upwardly curvilinear for the speeds used to measure MAOD; the relationship between demand and cycle ergometer work rate is linear; MAOD is greater in running than in cycling.

Electromyographic Activity and Rate of Muscle Fatigue of the Quadriceps Femoris During Cycling Exercise in the Severe Domain

This study compared the activation pattern and the fatigue rate among the superficial muscles of the quadriceps femoris (QF) during severe cycling exercise. Peak oxygen consumption (VO(2)peak) and maximal accumulated oxygen Deficit (MAOD) were established by 10 well-trained male cyclists (27.5 ± 4.1 years, 71.0 ± 10.3 kg, 173.4 ± 6.6 cm, mean VO(2)peak 56.7 ± 4.4 ml·kg·min(-1), mean MAOD 5.7 ± 1.1 L). Muscle activity (electromyographic [EMG] signals) was obtained during the supramaximal constant workload test (MAOD) and expressed by root mean square (RMS) and median frequency (MF slope). The RMS of the QF, vastus lateralis (VL) and vastus medialis (VM) muscles were significantly higher than at the beginning after 75% of exercise duration, whereas for the rectus femoris (RF), this was observed after 50% of exercise duration (p ≤ 0.05). The slope of the MF was significantly higher in the RF, followed by the VL and VM (-3.13 ± 0.52 vs. -2.61 ± 0.62 vs. -1.81 ±0.56, respectively; p < 0.05). We conclude that RF may play an important role in limiting performance during severe cycling exercise.

A Semi-Tethered Test for Power Assessment in Running

We analyzed the usefulness of a semi-tethered field running test (STR) and the relationships between indices of anaerobic power, anaerobic capacity and running performance in 9 trained male sprinters (22.2 ± 2.9 yrs, 176 ± 1 cm, 68.0 ± 9.4 kg). STR involved an all out 120 m run attached to an apparatus that enabled power calculation from force and velocity measures. Subjects also carried out a cycloergometer Wingate Anaerobic Test (WT), an all out 300 m run and had accessed their maximal accumulated oxygen deficit (MAOD) on a treadmill. Peak and mean powers attained in STR (1720 ± 221 and 1391 ± 201 W) were greater but significantly related (r = 0.82; P < 0.01) to those in the WT (808 ± 130 and 603 ± 87 W). In addition, power measures derived from the STR were stronger related to running performance compared to those from the WT (r = 0.81-0.94 vs. 0.68-0.84; P < 0.05). Relationships between MAOD and most power indices were only weak to moderate. These results support the usefulness of STR for specific power assessment in field running and suggest that anaerobic power and capacity are not related entities, irrespective of having been evaluated using similar or dissimilar exercise modes.

Índices fisiológicos e neuromusculares relacionados à performance nas provas de 800 m e 1500 m rasos

O objetivo deste estudo foi determinar e correlacionar os indices fisiologicos e neuromusculares com a performance de corredores treinados nas distâncias de 800 m e 1500 m. Onze atletas realizaram os seguintes testes: 1) determinacao das performances nos 800 m e 1500 m; 2) determinacao do consumo maximo de oxigenio (VO2max), velocidade correspondente ao VO2max (vVO2max) e velocidade correspondente ao onset of blood lactate accumulation; 3) saltos verticais (Counter Movement Jump - CMJ e Continuous Jump - CJ); 4) determinacao do tempo de exaustao (Tlim) e 5) testes submaximos para determinacao da economia de corrida e teste supra-maximo para calculo do maximo deficit acumulado de oxigenio. Houve correlacao significante da vVO2max e do Tlim com as duas provas. O CJ se correlacionou somente com os 800 m. Conclui-se que a potencia aerobia e a principal determinante da performance nas duas distâncias, destacando-se que os aspectos neuromusculares influenciam os 800 m.

Effects Of Moderate Altitude Training On Total Hemoglobin Mass And Hematology In World Class Sprint Cyclists

Hematological adaptations to moderate altitude training have been described in elite endurance athletes. Altitude training has been associated with increases in total hemoglobin mass (tHb), maximum accumulated oxygen deficit and muscle buffering capacity in endurance athletes (1). However, relatively few investigations have focused on the effects of altitude training in sprint athletes. PURPOSE: To quantify the hematological response of sprint cyclists to 4wks of moderate altitude training. METHODS: The Australian Track Sprint Cycling Team (M=4; F=3) completed a 28d training camp at 1860m. Cyclists' hemoglobin concentration ([Hb]) and hematocrit (Hct) were measured pre-departure and day 25 at altitude, while body composition and tHb were determined on day 4 and day 25 of the 28d camp. The cyclists completed track training involving maximal efforts over distances ranging from 50 to 750m (∼27 hrs total), weight training (∼16 hrs total), road rides (∼18 hrs total) and cycle ergometer sessions (∼2 hrs total). Data are reported as mean±SD, paired t-test were conducted (p<0.05) and percent change from pre to post were calculated. RESULTS: There was a 4.5±2.5% increase in tHb (922.9±201.2 v 964.7±212.4 g: p=0.002), a 7.8±3.8% increase in [Hb] (152±8 v 164±6 g/L, p=0.001), and 9.2±4.4% increase in Hct (44.4±2.5 v 48.4±2.3%: p=0.001). The changes in blood volume (0.6±4.9%) and plasma volume (-2.5±7.0%) were not significant (p=0.62 and 0.42, respectively). Ferritin declined from 100±66 ug/L to 81±37 ug/L (p=0.17). Only one cyclist used oral iron supplements. There was ∼1 kg decrease in body mass (81.1±10.6 v 80.0±10.6 kg, p=0.05) without a significant change in sum of seven skinfolds (67.3±22.0 v 65.4±22.0 mm, p=0.19). CONCLUSION: Our results challenge the recommendation that ∼2200m is the minimal altitude required to increase tHb. These data extend previous altitude training research using endurance athletes (2) and demonstrate that similar gains in tHb (∼5% in 4wks) can occur in sprint cyclists who complete relatively low volume, high intensity training. Further research is required to determine the impact of these hematological changes on sprint cycling performance. 1. CJ Gore et al. Med.Sci.Sports Exerc. 39:1600-09, 2007. 2. LA Garvican et al. Med.Sci.Sports Exerc. 40:S52, 2008.

Time to Exhaustion and Time Spent at a High Percentage of V̇o2max in Severe Intensity Domain in Children and Adults

The aim of the study was to compare time spent at a high percentage of VO2max (>90% of VO2max) (ts90%), time to achieve 90% of VO2max (ta90%), and time to exhaustion (TTE) for exercise in the severe intensity domain in children and adults. Fifteen prepubertal boys (10.3 ± 0.9 years) and 15 men (23.5 ± 3.6 years) performed a maximal graded exercise to determine VO2max, maximal aerobic power (MAP) and power at ventilatory threshold (PVTh). Then, they performed 4 constant load exercises in a random order at PVTh plus 50 and 75% of the difference between MAP and PVTh (PΔ50 and PΔ75) and 100 and 110% of MAP (P100 and P110). VO2max was continuously monitored. The P110 test was used to determine maximal accumulated oxygen deficit (MAOD). No significant difference was found in ta90% between children and adults. ts90% and TTE were not significantly different between children and adults for the exercises at PΔ50 and PΔ75. However, ts90% and TTE during P100 (p < 0.05 and p < 0.01, respectively) and P110 (p < 0.001) exercises were significantly shorter in children. Children had a significantly lower MAOD than adults (34.3 ± 9.4 ml · kg vs. 53.6 ± 11.1 ml · kg). A positive relationship (p < 0.05) was obtained between MAOD and TTE values during the P100 test in children. This study showed that only for intensities at, or higher than MAP, lower ts90% in children was linked to a reduced TTE, compared to adults. Shorter TTE in children can partly be explained by a lower anaerobic capacity (MAOD). These results give precious information about exercise intensity ranges that could be used in children's training sessions. Moreover, they highlight the implication of both aerobic and anaerobic processes in endurance performances in both populations.

Anaerobic contribution during maximal anaerobic running test: correlation with maximal accumulated oxygen deficit

The aims of this study were: (i) to measure energy system contributions in maximal anaerobic running test (MART); and (ii) to verify any correlation between MART and maximal accumulated oxygen deficit (MAOD). Eleven members of the armed forces were recruited for this study. Participants performed MART and MAOD, both accomplished on a treadmill. MART consisted of intermittent exercise, 20 s effort with 100 s recovery, after each spell of effort exercise. Energy system contributions by MART were also determined by excess post-exercise oxygen consumption, lactate response, and oxygen uptake measurements. MAOD was determined by five submaximal intensities and one supramaximal intensity exercises corresponding to 120% at maximal oxygen uptake intensity. Energy system contributions were 65.4±1.1% to aerobic; 29.5±1.1% to anaerobic a-lactic; and 5.1±0.5% to anaerobic lactic system throughout the whole test, while only during effort periods the anaerobic contribution corresponded to 73.5±1.0%. Maximal power found in MART corresponded to 111.25±1.33 mL/kg/min but did not significantly correlate with MAOD (4.69±0.30 L and 70.85±4.73 mL/kg). We concluded that the anaerobic a-lactic system is the main energy system in MART efforts and this test did not significantly correlate to MAOD.

Assessment of Child-Specific Aerobic Fitness and Anaerobic Capacity by the Use of the Power-Time Relationships Constants

This study first aimed to compare critical power (CP) and anaerobic work capacity (AWC), to laboratory standard evaluation methods such as maximal oxygen uptake (VO(2)max) and maximal accumulated oxygen deficit (MAOD). Secondly, this study compared child and adult CP and AWC values. Subjects performed a maximal graded test to determine VO(2)max and maximal aerobic power (MAP); and four constant load exercises. In children, CP (W * kg(-1)) was related to VO(2)max (ml * kg(-1) * min(-1); r = .68; p = .004). AWC (J * kg(-1) in children was related to MAOD (r = .58; p = .018). Children presented lower AWC (J * kg(-1); p = .001) than adults, but similar CP (%MAP) values. CP (%MAP and W * kg(-1) and AWC (J * kg(-1) were significantly related to laboratory standard evaluation methods but low correlation indicated that they cannot be used interchangeably. CP (%MAP) was similar in children and adults, but AWC (J * kg(-1) was significantly lower in children. These conclusions support existing knowledge related to child-adults characteristics.

Relationship Between Maximal Accumulated Oxygen Deficit (MAOD) and the Wingate Anaerobic Power Test (WAnT)

Relationship Between Maximal Accumulated Oxygen Deficit (MAOD) and the Wingate Anaerobic Power Test (WAnT)

Predicting MAOD Using Only a Supramaximal Exhaustive Test

The objective of this study was to propose an alternative method (MAOD(ALT)) to estimate the maximal accumulated oxygen deficit (MAOD) using only one supramaximal exhaustive test. Nine participants performed the following tests: (a) a maximal incremental exercise test, (b) six submaximal constant workload tests, and (c) a supramaximal constant workload test. Traditional MAOD was determined by calculating the difference between predicted O(2) demand and accumulated O(2) uptake during the supramaximal test. MAOD(ALT) was established by summing the fast component of excess post-exercise oxygen consumption and the O(2) equivalent for energy provided by blood lactate accumulation, both of which were measured during the supramaximal test. There was no significant difference between MAOD (2.82+/-0.45 L) and MAOD(ALT) (2.77+/-0.37 L) (P=0.60). The correlation between MAOD and MAOD(ALT) was also high (r=0.78; P=0.014). These data indicate that the MAOD(ALT) can be used to estimate the MAOD.

The Maximal Accumulated Oxygen Deficit Method

The maximal accumulated oxygen deficit (MAOD) method has been extensively, but unfortunately not very methodically, used; the procedure used to determine the MAOD varies considerably. Therefore, this review evaluates the effect of different numbers and durations of submaximal exercise bouts on the linear power output (PO)-oxygen uptake ((.)VO2) relationship and thus the MAOD. Changing the number and duration of the submaximal exercise bouts substantially influences the calculated MAOD when relatively long submaximal exercise bouts are used and no fixed value of the y-intercept is forced into the linear regression line. This is most likely due to non-linearity of the PO-(.)VO2 relationship for exercise intensities above the lactate threshold (LT). Non-linearity of the PO-(.)VO2 relationship is probably caused by the development of a slow component in (.)VO2 during submaximal exercise at intensities above the LT. Thus, it is important to standardize the number, duration and intensity of submaximal exercise bouts necessary to establish the PO-(.)VO2 relationship. Beyond changing the number and duration of the submaximal exercise bouts, the effect of different supramaximal exercise bouts on the calculated MAOD has been investigated. While it has become clear that different exercise protocols result in relatively similar values of the MAOD, a closer look at individual data suggests that it may be important to choose an exercise protocol that is representative of the athlete's event. The validity of the MAOD method was studied by different authors comparing the MAOD with metabolic measurements of anaerobic adenosine triphosphate (ATP) production. The main limitation with the metabolic measurements of anaerobic ATP production from muscle biopsy data is that the active muscle mass is unknown, which makes it hard to accurately study the validity of the MAOD method. From the studies that evaluated the reliability of the MAOD method it is clear that the MAOD method may not be a reliable measure of anaerobic capacity. From these findings it can be concluded that the MAOD method may have limitations as a valid and reliable measure of anaerobic capacity and needs to be further improved. We suggest the use of 10 x 4 minute submaximal exercise bouts and a fixed value of the y-intercept for the construction of the linear PO-(.)VO2 relationship, after which the MAOD can be determined during a supramaximal exercise protocol specific for the athlete's event. This method will lead to a more robust PO-(.)VO2 relationship and will therefore result in more valid and reliable results.

Anaerobic And Performance Adaptations To A "Live High-Train Low" Approach Using Simulated Altitude Exposure

Physiologic adaptations and performance improvements have previously been demonstrated as a result of altitude exposure. However, debate continues regarding the mechanism (aerobic vs. anaerobic) involved in these improvements, as well as the optimal degree of exposure required to elicit such adaptations. PURPOSE: The purpose of this study was to determine if a seven-day "live high-train low" (LHTL) simulated altitude exposure could improve (a) anaerobic and/or aerobic capacity (maximal accumulated oxygen deficit (MAOD) and/or VO2peak) in trained cyclists and (b) VO2peak and/or 400 m swimming performance in NCAA Division I intercollegiate swimmers. METHODS: In procedures approved by the EMU Human Subjects Review Board, 18 competitive male athletes completed tests before and after LHTL in a cross-over design. Competitive cyclists (n=8) performed seven cycle ergometer trials (Velotron; Racermate, WA) to measure maximal mean power output for 4 min (MMPO4min), MAOD, and VO2peak. NCAA Division I swimmers (n=10) completed five incremental arm ergometer (SciFit, OK) trials (VO2peak) and four 400 m swimming performance trials. These tests were performed to measure adaptations to a LHTL protocol consisting of sleeping at a simulated altitude of 2,500 m for 7 nights for 8-12 h each night. The results of these tests were analyzed by ANOVA and MANOVA (SPSS 16, IL, a=0.05) analyses. RESULTS: Baseline values for the cyclists' VO2peak, MAOD, and MMPO4min (4437 ml/min, 3863 ml/min, and 352 W, respectively) did not exhibit significant changes as a result of the control or LHTL treatment. Likewise, the swimmers' pre-treatment values for VO2peak and 400 m performance trials (3386 ml/min and 4 min 49 s, respectively) did not show significant changes as a result of the control or LHTL treatment. Sleep quality appeared to drop initially, but tended (p=0.08) to progressively increase by 25% from day 1 to day 5 of LHTL exposure. CONCLUSION: A 7 d simulated altitude exposure of 2,500 m for 8.5 h each night is insufficient to result in changes in MAOD, VO2peak, or performance among highly trained cyclists and swimmers. It is possible that a reduction in sleep quality due to the simulated altitude exposure hindered the athletes' ability to perform.

Effect Of Caffeine Ingestion After Creatine Supplementation On High-intensity Cycling Sprint Performance

Previous studies showed that ingestion of caffeine together with creatine may inhibit the effects of creatine on anaerobic exercise. Although some studies indicated that ingested caffeine after short-term creatine supplementation could increase maximal accumulated oxygen deficit, there was no evidence to prove whether this supplementary method could facilitate stop-and-go exercise performance. PURPOSE: This study was to investigate the effects of caffeine ingestion after creatine supplementation on intermittent high-intensity cycling sprints performance. METHODS: Twelve physically active men were administered in a double-blind, randomized, counterbalanced design to perform intermittent high-intensity sprints (6×10-s; repeated at 60-s intervals, HIS) on a cycling ergometer with or without caffeine ingestion. After short-term creatine monohydrate supplementation (0.3 g · kg-1 · day-1, 5 days), subjects ingested 6 mg · kg-1 caffeine or placebo (maltodextrin) 1 hour before HIS trials. Heart rate was monitored continuously throughout the tests, with rating of perceived exertion (RPE) recorded after each sprint. Earlobe blood samples were also drawn immediately after each sprint to evaluate lactate and glucose concentrations. RESULTS: Compared with placebo, caffeine did not resulted in higher maximal power output (842.3±102.2 vs. 813.5±95.3 watts, p>0.05). However, the relative peak power output in caffeine treatment was significantly higher than in placebo during the first sprint (11.7±0.7 vs. 11.3±0.7 watts · kg-1, p<0.05) and second sprint (11.5±0.7 vs. 10.8±0.7 watts · kg-1, p<0.05). Heart rates were significantly increased with caffeine treatment from the third sprint to the final sprint, and the blood lactate and glucose concentrations were also significantly elevated through the HIS trial. Furthermore, there were no significant effects of caffeine ingestion on the RPE scores. CONCLUSIONS: The present study showed that caffeine ingestion after short-term creatine supplementation could improve intermittent high-intensity sprints performance, but might also induce higher metabolic stress.

DÉFICIT MÁXIMO ACUMULADO DE OXIGÊNIO: UMA BREVE REVISÃO HISTÓRICA E METODOLÓGICA - DOI: 10.4025/reveducfis.v19i1.4323

The total capacity for anaerobic ATP resynthesis (AC) seems to be fundamental to the performance in sport modalities with short duration and high intensity. Thus, several methods were suggested for the measurement of AC, but the maximal accumulated oxygen deficit (MAOD) had been considered a more appropriated method. Therefore, the objective of this study was to review systematically how the MAOD method was improved along the years. Summarizing, the validity and reproducibility of MAOD were presented by scientific literature from different perspectives. However, this method’s measurements can be slower and more expensive. Therefore, it would be valuable if the future studies were performed aiming to propose and to validate alternative methods to MAOD estimation, which should employ physiological variables that are indirectly associated to aerobic metabolism as the heart rate. Thus, these methods could be useful to facilitate this measurement to physical education teachers and other professionals of correlated areas.

DÉFICIT MÁXIMO ACUMULADO DE OXIGÊNIO: UMA BREVE REVISÃO HISTÓRICA E METODOLÓGICA

The total capacity for anaerobic ATP resynthesis (AC) seems to be fundamental to the performance in sport modalities with short duration and high intensity. Thus, several methods were suggested for the measurement of AC, but the maximal accumulated oxygen deficit (MAOD) had been considered a more appropriated method. Therefore, the objective of this study was to review systematically how the MAOD method was improved along the years. Summarizing, the validity and reproducibility of MAOD were presented by scientific literature from different perspectives. However, this method’s measurements can be slower and more expensive. Therefore, it would be valuable if the future studies were performed aiming to propose and to validate alternative methods to MAOD estimation, which should employ physiological variables that are indirectly associated to aerobic metabolism as the heart rate. Thus, these methods could be useful to facilitate this measurement to physical education teachers and other professionals of correlated areas.

Time Spent At High Percentage Of Vo2max In Children And Adults

PURPOSE: Time to exhaustion (TTE) and time spent at high percentage of VO2max (>90% VO2max; tVO2max) have been widely studied in adults. During exercise, once VO2max is achieved, tVO2max is dependent of TTE. As children present specific physiological responses to exercise when compared to adults, the aim of this study was to compare TTE and tVO2max at different intensities in children and adults. METHODS: Sixteen prepubertal boys (10.3 ±0.9yrs; 43.7 ±5.1ml.kg−1.min−1) and fifteen males adults (23.5 ±3.6yrs; 46.4 ±6.0ml.kg−1.min−1) performed a maximal graded test on cycle-ergometer to determine VO2max, power at ventilatory threshold (PVT) and maximal aerobic power (MAP); and in a random order four TTE trials at four different intensities: Pα50, Pα75, P100 and P110, where Pα50 and Pα75 corresponded to 50 and 75% of the difference between MAP and PVT, respectively. P100 and P110 corresponded to 100 and 110% of MAP, respectively. During each trial, VO2 was continuously measured. P110 test was used in order to determine maximal accumulated oxygen deficit (MAOD). RESULTS: No significant difference was observed between children and adults TTE for PΔ50 (792 ±455s vs 754 ±334s) and PΔ75 (310 ±147s vs 371 ±111s), while children demonstrated significantly shorter TTE for P100 (153 ±67s vs 221 ±49s, p<0.01), and P110 (98 ±30s vs 147 ±23s, p<0.001) trials. Similarly, no significant difference was observed for tVO2max between children and adults for PΔ50 (605 ±482s vs 482 ±307s) and PΔ75 (211±167s vs 233 ±116s), while the tVO2max were significantly shorter in children for P100 (60 ±83s vs 137 ±63s, p<0.01) and P110 (36 ±34s vs 83 ±38s, p<0.001) trials. Children had a significantly lower MAOD than adults (709.9 ±187.9J.kg−1 vs 1120.0 ±232.2J.kg−1, p<0.001). For the whole population, a significant relationship was obtained between MAOD and TTE values during P100 test (r=0.47; p<0.001). CONCLUSIONS: This study showed that for sub-maximal intensities children had similar TTE and tVO2max compared to adults. For maximal intensity (P100), children had a shorter TTE and tVO2max than adults. This result can partly be explained by a significantly lower MAOD (ie: an index of anaerobic capacity), that is determinant in maximal (P100) and supra-maximal (P110) performances but not in submaximal performances (PΔ50, PΔ75).

A comparison of methods to determine maximal accumulated oxygen deficit in running

The aim of this study was to compare maximal accumulated oxygen deficit (hereafter O2 deficit) estimated from the methods of Whipp et al. (1986), Medbo et al. (1988), and Hill et al. (1998) to determine whether they agree sufficiently to be used interchangeably. Nineteen moderately to highly trained endurance runners first performed an incremental test to exhaustion for the determination of maximal oxygen uptake ([Vdot]O2max) and peak treadmill speed, followed by six randomly ordered constant-speed tests at 95, 100, 105, 110, 110, and 120% of peak treadmill speed. All tests were separated by at least 72 h and were performed within 4 weeks. The method of Whipp produced an O2 deficit estimate that was lower than that derived from the method of Hill or Medbo (bias ± 95% limits of agreement: −29.6 ± 36.6 and −26.1 ± 32.8 ml · kg−1, respectively; P < 0.001). The O2 deficit did not differ between the methods of Hill and Medbo (bias ± 95% limits of agreement: 3.5 ± 41.6 ml · kg−1; n.s.). However, poor correlations (0.21 < r < 0.33; n.s.) together with wide limits of agreement between O2 deficit estimates (70 – 80% of the mean response) clearly question using these methods interchangeably.

Anaerobic and aerobic relative contribution to total energy release during supramaximal effort in patients with left ventricular dysfunction

Energetic metabolism during effort is impaired in patients with left ventricular dysfunction (Dysf), but data have been lacking up to now on the relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort. Recently, the maximal accumulated oxygen deficit (MAOD) has been shown to be measurable in Dysf patients, making it possible to evaluate the anaerobic/aerobic interaction under conditions of maximal stress of both anaerobic and aerobic metabolic pathways in this population. Nineteen Dysf patients and 17 normal patients (N) underwent one ramp cardiopulmonary, three moderate-intensity constant-power, and three supramaximal constant-power (1- to 2-min, 2- to 3-min, and 3- to 4-min duration) exercise tests. MAOD was the difference between accumulated O(2) demand (accO(2)dem; estimated from the moderate-intensity O(2) uptake/watt relationship) and uptake during supramaximal tests. Percent anaerobic (%Anaer) and aerobic (%Aer) energetic release were [(MAOD/accO(2)dem).100] and 100 - %Anaer, respectively. MAOD did not vary between 1-2, 2-3, and 3-4 min supramaximal tests, whereas accO(2)dem increased significantly with and was linearly related to test duration in both Dysf and N. Consequently, %Anaer and %Aer decreased and increased, respectively, with increasing test duration but did not differ between Dysf and N in 1-2 min, 2-3 min, and 3-4 min tests. Our study demonstrates a similar relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort in Dysf and N. This finding indicates that energetic metabolism during supramaximal exercise is exercise tolerance independent and that relative anaerobic vs. aerobic contribution in this effort domain remains the same within the physiology- or pathology-induced limits to individual peak exercise performance.

Effects of acute moderate hypoxia on anaerobic capacity in endurance-trained runners

While there is some controversy whether anaerobic capacity might be improved after altitude training little is known about changes in anaerobic capacity during hypoxic exposure in highly trained athletes. In order to analyze the effects of acute moderate normobaric hypoxia on anaerobic capacity, 18 male competitive triathletes, middle- and long-distance runners VO2max 67.4 +/- 3.8 ml kg min(-1) performed 2 supra-VO2max treadmill runs with the same speed, one in normoxia and one after 4 h exposure to normobaric hypoxia (FiO(2) 0.15), for estimation of their maximal accumulated oxygen deficit (MAOD) and measurement of peak capillary lactate and peak capillary ammonia concentration. MAOD was not significantly different in normoxia and in moderate hypoxia while time to exhaustion and accumulated O(2) uptake were significantly (P < 0.001) reduced in hypoxia compared to normoxia by 28 and 45%, respectively. The reduction in time to exhaustion was significantly correlated to the decrement in accumulated O(2) uptake (R = 0.730, P = 0.001). In hypoxia, there was a tendency for peak capillary lactate concentration to be decreased compared to normoxia (12.9 +/- 2.1 vs. 13.8 +/- 2.2 mmol l(-1), P = 0.082); peak capillary ammonia concentration was significantly decreased in hypoxia (97 +/- 52 vs. 121 +/- 44 micromol l(-1), P = 0.032). In conclusion, anaerobic capacity is not significantly changed during acute exposure to moderate hypoxia in endurance-trained athletes. The performance reduction during all-out exercise of short duration has to be attributed to the decrement in aerobic capacity.