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.     

Re-assessing accumulated oxygen deficit in middle-distance runners

The purpose of this study was to re-assess the accumulated oxygen deficit (AOD), incorporating recent methodological improvements i.e., 4 min submaximal tests spread above and below the lactate threshold (LT). We Investigated the Influence of the VO2 -speed regression, on the precision of the estimated total energy demand and AOD. utilising different numbers of regression points and including measurement errors. Seven trained middle-distance runners (mean +/- SD age: 25.3 +/- 5.4y, mass: 73.7 +/- 4.3kg. VO2max 64.4 +/- 6.1 mL x kg(-1) x min(-1)) completed a VO2max, LT, 10 x 4 min exercise tests (above and below LT) and high-intensity exhaustive tests. The VO2 -speed regression was developed using 10 submaximal points and a forced y-intercept value. The average precision (measured as the width of 95% confidence Interval) for the estimated total energy demand using this regression was 7.8mL O2 Eq x kg(-1) x min(-1). There was a two-fold decrease in precision of estimated total energy demand with the Inclusion of measurement errors from the metabolic system. The mean AOD value was 43.3 mL O2 Eq x kg(-1) (upper and lower 95% CI 32.1 and 54.5mL o2 Eq x kg(-1) respectively). Converting the 95% CI for estimated total energy demand to AOD or including maximum possible measurement errors amplified the error associated with the estimated total energy demand. No significant difference in AOD variables were found, using 10,4 or 2 regression points with a forced y-intercept. For practical purposes we recommend the use of 4 submaximal values with a y-intercept. Using 95% CIs and calculating error highlighted possible error in estimating AOD. Without accurate data collection, increased variability could decrease the accuracy of the AOD as shown by a 95% CI of the AOD.     

Effect of training on accumulated oxygen deficit and shuttle run performance

BACKGROUND: The purpose of the present study was to investigate changes in physiological, metabolic and performance parameters resulting from an intense 6 week training programme. METHODS: Sixteen volunteers were divided into a control (CN; 4 men and 2 women) and training group (TR; 6 men and 4 women). Laboratory measures included maximal aerobic power (VO2max), submaximal oxygen uptake (10.5 percent or 6 degrees treadmill inclination) and accumulated oxygen deficit (AOD). Performance was assessed during 20 metre shuttle run tests (PST, progressive shuttle run test; HIST, high intensity shuttle run test). RESULTS: TR improved their HIST performance (m) significantly compared with CN, identified by a significant "group-by-training" interaction (p<0.01). Similarly, AOD values improved more in TR compared with CN (p<0.01). There was a trend for TR to further reduce blood pH values after training compared with CN, although this decrease (approximately 0.05 units) did not attain statistical significance. The change in AOD was strongly correlated with the change in run time to exhaustion (r=0.76, p<0.01) and the change in estimated total work output (r=0.69, p<0.01) during 10.5 percent gradient running and modestly correlated with the change in HIST performance (r=0.49, p<0.05, assuming a directional test). CONCLUSIONS: The results of the present study suggest changes in the anaerobic capacity, determined as AOD, due to training may be reflected in corresponding changes in laboratory and field performance.     

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

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.     

Maximal accumulated oxygen deficit and blood responses of ammonia, lactate and pH after anaerobic test: a comparison between international and national elite karate athletes

The purpose of this study was to compare maximal accumulated oxygen deficit (MAOD) and the time course of blood markers of the anaerobic metabolism in response to exhaustive supramaximal test in two elite (international vs. national) class karate athletes. Ten male international competitors from the French national team (Int, age 21.2 +/- 3.1 years, 71.9 +/- 11.4 kg) and eight national class (Nat, 23.7 +/- 2.4 years, 70.7 +/- 12.2 kg) athletes with a similar maximal oxygen uptake of 57.6 and 59.4 ml . kg (-1) . min (-1), respectively, were involved in this study. The MAOD was determined after an exhaustive supramaximal exercise (2 - 3 min at 140 % of their VO2max velocity) on a treadmill ergometer. Blood lactate, pH and plasma ammonia were determined at rest, immediately at the end of exercise and during the recovery period at 2, 4, 6, 8, 10 and 15 min. After the supramaximal exercise, a dramatic higher increase in the blood concentration of ammonia until its peak was observed in the Nat compared with the Int. Time course of [NH4+] and [La] reveals significant (p < 0.01) differences between the two groups. Peak values for [H+] (89.2 +/- 6.7 vs. 75.9 +/- 8.8 nmol . l (-1); p < 0.01), [NH4+] (180 +/- 67.9 vs. 118.7 +/- 22.7 micromol . l (-1); p < 0.05) and [La] (20.7 +/- 2.7 vs. 17.9 +/- 1.1 mmol.l (-1); p < 0.05) were higher in Nat compared with Int group, respectively. However, the MAOD was similar in both groups (67.8 +/- 8 ml . kg (-1) and 64.5 +/- 6.4 for Int and Nat groups, respectively). These data suggest that ammonia and lactate accumulation are sensitive to the level of performance in karate. Higher concentrations of these metabolites in blood after supramaximal exhaustive exercise may be related to either higher anaerobic contribution to energy supply in Nat or higher removal ability in the Int group.     

Maximal accumulated oxygen deficit is influenced by chronological age and is related to intensity of VO2PEAK

Sport Sciences for Health - This study aimed to verify the influence of chronological age on maximal accumulated oxygen deficit (MAOD) and the correlations with maximal oxygen uptake (VO2PEAK) and...     

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.     

The renal washout parameter as an indicator of transplant rejection

The accumulation of intravascular fibrin thrombosis in both acute and chronic renal rejection leads to a delay in the transit of perfusion. This study examines the renal washout parameter as an indicator of transit time. By mathematical simulation of renal time-activity curves various factors which can influence this parameter are investigated, a simple analysis is proposed and clinical results are correlated with biopsy findings. A washout parameter greater than 28 s is found to be consistent with histologically diagnosed rejection over a range of bolus qualities.     

The renal washout parameter as an indicator of transplant rejection

The accumulation of intravascular fibrin thrombosis in both acute and chronic renal rejection leads to a delay in the transit of perfusion. This study examines the renal washout parameter as an indicator of transit time. By mathematical simulation of renal time-activity curves various factors which can influence this parameter are investigated, a simple analysis is proposed and clinical results are correlated with biopsy findings. A washout parameter greater than 28 s is found to be consistent with histologically diagnosed rejection over a range of bolus qualities.     

Pain as an indicator of bone metastasis

Patients with breast or prostate cancer routinely referred for bone scintigraphy were evaluated for the presence of skeletal pain, as determined by a self administered questionnaire. Pain was a common finding, whether or not metastatic disease was present, and occurred in over half of patients. Although most patients with bone metastases did report bone pain, a significant fraction (21% of breast and 22% of prostate patients) were asymptomatic. A distinct minority of individual anatomic regions of metastasis were painful: pain was reported in 23% of sites of breast metastases and 15% of metastatic prostate cancer sites. Of all sites at which pain was present, metastases were demonstrated in only about one half. These results indicate that pain is not a reliable indicator of the presence of location of metastatic bone disease.     

Development of an anaerobic capacity test for field sport athletes.

Maximally accumulated oxygen deficit (MAOD) has been argued to be currently the best non-invasive method for estimating anaerobic capacity (Medb? et al., 1988, Ramsbottom et al., 1997). An easy to administer field test that could accurately predict MAOD, would be of great use to many field sport athletes and coaches. Fifteen male rugby union players undertook MAOD testing (99.4 +/- 16.9ml x kg(-1)) on a treadmill using a modification of procedure 3 as described by Medb? et al. (1988). All subjects also performed a 300m Shuttle Run Test (66.7 +/- 2.2s), run over a 20m distance. Analysis of the MAOD and 300m Shuttle Run Test time relationship revealed a significant correlation of r = -0.69 [p<0.01). Furthermore, a one-way analysis of variance (ANOVA) revealed that when subjects were split into 'good' and 'poor' groups based on 300m Shuttle Run Test times, the times distinguished between 'good' and 'poor' MAOD values (P<0.05). The findings of the present study support the validity of the 300m Shuttle Run Test as a useful estimate of anaerobic capacity in football athletes. Unexplained variance could be due to speed and agility factors associated with the 300m Shuttle Run Test. Methodological issues pertaining to the accurate assessment of MAOD are also discussed.     

Pulmonary embolism as an indicator of occult malignancy

A case that demonstrates the relationship between malignancy and pulmonary throboembolic disease is presented. Pulmonary embolism, which was diagnosed on a ventilation-perfusion lung scan, initiated a search for the etiology of this condition. Normal examination of the deep venous system of the legs prompted further investigation, which ultimately led to the endoscopic diagnosis of poorly differentiated gastric carcinoma.     

Tongue protrusion as an indicator of vital burning

In the forensic assessment of burned bodies, the question of whether the victim was exposed to the fire before or after death is of crucial importance. Several external signs have been used in the past to indicate heat exposure prior to the death of the victim but these did not include tongue protrusion. The internal signs of heat exposure are generally regarded as much more important than those observed externally. No one factor has been found to be totally reliable. This study found a statistically significant dependence between tongue protrusion and presence of soot in the respiratory tract and stomach, the latter being a good indicator of vital burning. The results of this study confirm that tongue protrusion can be used as an additional indicator of vital burning.     

Rectal fold thickness as an indicator of disease

Rectal folds are seen best in the lateral view. Normal values for the thickness of the folds have been established by measuring these in patients with a diagnosis of irritable bowel syndrome who had no evidence of rectal disease. In severe ulcerative colitis the valves disappear, but they are present earlier in the disease. The first barium enema examination in patients with ulcerative colitis was assessed. When the valve thickness could be measured in these patients it showed values significantly greater than normal. It is uncommon for this finding to be the sole indicator of disease. Patients with Crohn's disease of the rectum showed no increase in the fold thickness. This observation may be helpful in distinguishing between these two forms of colitis.     

Maximal oxygen uptake as a parametric measure of cardiorespiratory capacity

INTRODUCTION: Maximal oxygen uptake (.VO2max) was defined by Hill and Lupton in 1923 as the oxygen uptake attained during maximal exercise intensity that could not be increased despite further increases in exercise workload, thereby defining the limits of the cardiorespiratory system. This concept has recently been disputed because of the lack of published data reporting an unequivocal plateau in .VO2 during incremental exercise. PURPOSE: The purpose of this investigation was to test the hypothesis that there is no significant difference between the .VO2max obtained during incremental exercise and a subsequent supramaximal exercise test in competitive middle-distance runners. We sought to determine conclusively whether .VO2 attains a maximal value that subsequently plateaus or decreases with further increases in exercise intensity. METHODS: Fifty-two subjects (36 men, 16 women) performed three series of incremental exercise tests while measuring .VO2 using the Douglas bag method. On the day after each incremental test, the subjects returned for a supramaximal test, during which they ran at 8% grade with the speed chosen individually to exhaust the subject between 2 and 4 min. .VO2 at supramaximal exercise intensities (30% above incremental .VO2max) was measured continuously. RESULTS: .VO2max measured during the incremental test (63.3 +/- 6.3 mL.kg(-1).min(-1); mean +/- SD) was indistinguishable from the .VO2max during the supramaximal test (62.9 +/- 6.2, N = 156; P = 0.77) despite a sufficient duration of exercise to demonstrate a plateau in .VO2 during continuous supramaximal exercise. These data provide strong support for the hypothesis that there is indeed a peak and subsequent plateau in .VO2 during maximal exercise intensity. CONCLUSIONS: .VO2max is a valid index measuring the limits of the cardiorespiratory systems' ability to transport oxygen from the air to the tissues at a given level of physical conditioning and oxygen availability.