Article

Reliability of the 3-Component Model of Aerobic, Anaerobic Lactic, and Anaerobic Alactic Energy Distribution (PCr-LA-O2) for Energetic Profiling of Continuous and Intermittent Exercise

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Abstract

Purpose: To assess the test-retest reliability of the continuous (PCr-LA-O2) and intermittent (PCr-LA-O2int) version of the 3-component model of energy distribution in an applied setting. Methods: Sixteen male handball players (age 23 [3] y, height 185 [7] cm, weight 85 [14] kg) completed the 30-15 Intermittent Fitness Test (30-15IFT) twice. Performance was assessed by peak speed (speed of the last successfully completed stage of the 30-15IFT [VIFT], in kilometers per hour) and time to exhaustion (in seconds). Oxygen uptake (in milliliters per kilogram per minute) and blood lactate concentrations (in millimoles per liter) were obtained before, during, and until 15 minutes after exercise. Total metabolic energy (in joules per kilogram), total metabolic power (in watts per kilogram), and energy shares (in joules per kilogram and percentage) of the aerobic (energy contribution of the aerobic system [WAERint]), anaerobic lactic, and anaerobic alactic (anaerobic alactic energy [WPCrint]) systems were calculated using both model versions, respectively. Results: Test-retest reliability was very good for VIFT (limits of agreement [LoA]: -1.13 to 0.63 km·h-1, coefficient of variation [CV%] 1.68), time to exhaustion (LoA: -101 to 38 s, CV% 2.92), peak oxygen uptake (LoA: -2.68 to 4.04 mL·min-1·kg-1, CV% 1.48), and peak heart rate (-6.9 to 7.7 beats·min-1, CV% 1.1), but moderate for change in blood lactate concentration (LoA: -3.84 to 4.07 mmol·L-1, CV% 11.43). Reliability of the modeled total energy and its fractions were high for total metabolic energy (LoA: -1489 to 1177 J·kg-1, CV% 2.88), total metabolic power (LoA: -2.0 to 1.9 W·kg-1, CV% 3.58), contribution of aerobic (LoA: -1673 to 1283 J·kg-1, CV% 3.62), WAERint (LoA: -1760 to 2160 J·kg-1, CV% 6.04), and moderate for anaerobic alactic (LoA: -368 to 439 J·kg-1, CV% 14.85), WPCrint (LoA: -1707 to 988 J·kg-1, CV% 9.98), and energy share of anaerobic lactic concentration (LoA: -229 to 235 J·kg-1, CV% 11.43). Conclusion: Considering the inherent fluctuations of the underlying energetics, the reliabilities of both versions of the 3-component model of energy distribution are acceptable for applied settings.

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Purpose: To analyze the energetic profile of the basketball exercise simulation test (BEST). Methods: 10 male elite junior basketball players (age: 15.5±0.6yrs, height: 180±9cm, body mass: 66.1±11.2kg) performed a modified BEST (20 circuits consisting of jumping, sprinting, jogging, shuffling, and short breaks) simulating professional basketball game play. Circuit time, sprint time, sprint decrement, oxygen uptake (VO2), heart rate (HR), and blood lactate concentration (BLC) were obtained. Metabolic energy and metabolic power above rest (Wtot, Ptot) as well as energy share in terms of aerobic (Waer), glycolytic (Wblc), and high energy phosphates (WPCr) were calculated from VO2 during exercise, net lactate production, and the fast component of post-exercise VO2 kinetics, respectively. Results: Waer, Wblc, and WPCr reflect 89±2%, 5±1%, and 6±1% of total energy needed, respectively. Assuming an aerobic replenishment of PCr energy stores during short breaks, the adjusted energy share yielded Waer: 66±4%, Wblc: 5±1%, and WPCr: 29±1%. Waer and WPCr were negatively correlated (-0.72, -0.59) with sprint time, which was not the case for Wblc. Conclusions: Consistent with general findings on energy system interaction during repeated high intensity exercise bouts, the intermittent profile of the BEST relies primarily on aerobic energy combined with repetitive supplementation by anaerobic utilization of high energy phosphates.
Article
The O2 debt determined as the O2 uptake deficit at the beginning of exercise may be entirely attributed to the depletion of O2 stores and to the hydrolysis of high energy phosphates as the lactic acid formation in the isolated dog gastrocnemius preparation is very small and taking place at a constant rate from the beginning of stimulation.The lactic acid concentration in the muscle is roughly equal to that in effluent blood both at rest and during exercise.
Article
Previous studies of intraindividual variation in running economy have not compared within-subject variability between groups of runners differing in training level, nor have they considered the workload of the submaximal but relative to the lactate breakpoint. Therefore, the purpose of the present study was to assess intraindividual variation in submaximal oxygen consumption (VO2) during steady rate treadmill running below the lactate breakpoint in highly trained (n = 7) and moderately trained (n = 8) male runners. Subjects completed a discontinuous VO2 max protocol with blood sampling to determine the lactate breakpoint. Three 15 minute level treadmill bouts at approximately 88% of the lactate breakpoint were then performed. Time of day, day of the week, diet, and and footwear were controlled within each subject across the three tests. Statistically significant differences were found between groups in VO2 max, relative fat, training mileage, and 10 km race time (p < 0.01), while the lactate breakpoint was similar between groups (integral of 80% of VO2 max). The difference in treadmill speed between highly trained and moderately trained runners for the submaximal bouts was statistically significant (p < 0.01) and correlated with reported training paces (r = 0.82). Although the mean coefficient of variation for steady rate VO2 was smaller for the highly trained group, the difference was not statistically significant (highly trained = 1.77%, moderately trained = 2.00%; p > 0.05). The mean coefficient of variation for all 15 subjects was 1.90%. After accounting for technological error, biological variation was found to comprise approximately 94% of the intraindividual variation in running economy. In comparison to other studies, these results suggest that workloads below the lactate breakpoint may allow more stable measures of running economy to be obtained.
Article
Portable indirect calorimetry systems offer the advantage of field-based measurements, but manufacturers rarely provide data about validity or reliability. In this study, we evaluated the validity and reliability of the Cortex MetaMax3B portable metabolic system. Validity was determined by comparing MetaMax3B results against those from a first-principles metabolic calibrator and an automated Douglas bag system. Reliability was obtained from duplicate exercise tests completed by eight athletes. Participants completed three identical incremental rowing tests on a Concept2 ergometer; two tests used the MetaMax3B and one test used the Douglas bag system. Compared with the metabolic calibrator, the MetaMax3B results were within 0.20 litres . min(-1) (7.8%) and 6.15 litres . min(-1) (4.0%) for [Vdot]O(2) and V(E), respectively. During exercise, the MetaMax3B results were within 0.16 litres . min(-1) (4.1%; [Vdot]O(2)), 0.32 litres . min(-1) (7.7%; [Vdot]CO(2)), and 3.22 litres . min(-1) (4.9%; V(E)) compared with the Douglas bag system. The MetaMax3B results were significantly higher for [Vdot]O(2) (P = 0.03) and [Vdot]CO(2) (P < 0.001). The typical error from duplicate exercise tests using the MetaMax3B ranged from 2.0% ([Vdot]O(2)) to 3.6% (V(E)). Our results show that the MetaMax3B provides reliable measurements of metabolic demand with adequate validity for field-based measurements.
The total and alactic oxygen debts were measured in eight subjects following supramaximal treadmill running (14.5--16.1 km/h, 20% grade) to exhaustion, on two duplicate tests separated by 48 h. Mean total oxygen debts on the two trials were 5.28 +/- 0.42 1 and 4.57 +/- 0.46 1, (r = 0.34). Mean alactic oxygen debts were 2.81 +/- 0.21 1 and 2.74 +/- 0.121 (r = 0.89). Values for maximal total and alactic oxygen debts in this study were in close agreement to those found in the literature. The inability of the subjects to adequately reproduce an exhausting supramaximal effort was the major factor preventing reliable measurement of total oxygen debt. It is concluded that the method developed for the measurement of oxygen debt is both reliable and valid for the alactic portion of the debt.
Article
Hultman, E., Bergström, J. & McLennan Anderson, N. Breakdown and Resynthesis of Phosphorylcreatine and Adenosine Triphosphate in Connection with Muscular Work in Man. Scand. J. clin. Lab. Invest. 19 56–66, 1967. Needle biopsies were performed in the m. quadriceps femoris of normal subjects, at rest and in connection with work on a bicycle ergometer. The concentrations of PC and ATP were determined in the biopsy material. The normal values in resting muscle were as follows: ATP 2.43 mmole per 100 g dry muscle (S.D. 0.21), PC 6.78 mmole per 100 g dry muscle (S.D. 0.70). The PC concentration was found to decrease rapidly during the first 2 minutes of continuous work, then remaining at a relatively constant level. The resynthesis of PC after work is complete within a few minutes. It has been demonstrated that a reverse relationship exists between the work load and the PC concentration in the muscle during work. At very high work loads the PC concentration decreases rapidly down to zero and the contractive capacity of the muscles ceases. When the glycogen store is considerably decreased, the PC level at work is lower than when work with the same load is carried out with the glycogen store intact. The ATP concentration also decreases during the first minutes of work, but during continuous work with low or moderately high loads the concentration of ATP tends to return to the basal level. At heavy work with pronounced decreases of PC, the ATP concentration also stays decreased. When the PC level is near zero the ATP decrease is approximately 40 per cent of the basal value.
Article
The aim of this study was to assess the validity and reliability of the Biosen 5030 lactate analyzer compared with a YSI 2300 lactate analyzer and a Kodak Ektachem DTII in a practical laboratory study context. To assess validity, 144 triplicate capillarized blood samples, across a range of values, were analyzed using the three analyzers. To assess reliability a further 665 samples were repeat analyzed. Temporal stability was determined by the reanalysis of resting and maximal exercise blood samples, after a period of storage ranging from 7 to 20 h, at room temperature. To measure inter- and intra-investigator reliability, 20 resting samples were taken from three different subjects by different investigators and a coefficient of variation was determined. There were strong relationships between the Biosen, the YSI (r2 = 0.97), and the Kodak Ektachem (r2 = 0.91). An analysis of Biosen compared with YSI revealed a positive bias of 0.37 mmol x L(-1) (95% limits of agreement, -0.85 to 1.59 mmol x L(-1)). The test-retest reliability correlation was significant (r2 = 0.99, P < 0.05), but a paired t-test revealed a small (0.03 mmol x L(-1), P < 0.05) significant difference. The coefficient of variation from the three investigators across the 20 samples ranged from 1.3 to 3%. Blood lactate concentration in resting blood samples did significantly increase in value (0.2 mmol x L(-1), P < 0.05) after 7-h exposure to the air, whereas there was no change in maximal exercise blood lactate values after 20-h exposure to the air. In a practical context, the Biosen 5030 lactate analyzer was comparable to the other analyzers giving fast reliable measures of blood lactate concentrations over the full range of values, which remained stable over extended periods at room temperature.
Article
The aim of this study was to determine the reproducibility of the maximal accumulated oxygen deficit and the associated exercise time to exhaustion during short-distance running. Fifteen well-trained males (mean +/- s: VO2max = 58.0+/-4.6 ml x kg(-1) x min(-1)) performed the maximum accumulated oxygen deficit test at an exercise intensity equivalent to 125% VO2max. The test was repeated at the same time of day on three occasions within 3 weeks. There was no significant systematic bias between trials for either maximum accumulated oxygen deficit (man +/- s: trial 1 = 69.0+/-13.1; trial 2 = 71.4+/-12.5; trial 3 = 70.4+/-15.0 ml O2 Eq x kg(-1); ANOVA, F = 0.70, PP= 0.51) or exercise time to exhaustion (trial 1 = 194 + 31.1; trial 2 = 198 + 33.2; trial 3 = 201 + 36.8 s; F= 1.49, P = 0.24). In addition, other traditional measures of reliability were also favourable. These included intraclass correlation coefficients of 0.91 and 0.87, and sample coefficients of variation of 6.8% and 5.0%, for maximum accumulated oxygen deficit and exercise time to exhaustion respectively. However, the '95% limits of agreement' were 0+/-15.1 ml O2 Eq (1.01 multiply/divide 1.26 as a ratio) and 0+/-33.5 s (1.0 multiply/divide 1.18 as a ratio) for maximum accumulated oxygen deficit and exercise time to exhaustion respectively. We estimate that the sample sizes required to detect a 10% change in exercise time to exhaustion and maximum accumulated oxygen deficit after a repeated measures experiment are 10 and 20 respectively. Unlike the results of previous maximum accumulated oxygen deficit studies, we conclude that it is not a reliable measure.
Article
1. The maximal oxygen uptake (V(O(2),peak)) during dynamic muscular exercise is commonly taken as a crucial determinant of the ability to sustain high-intensity exercise. Considerably less attention, however, has been given to the rate at which V(O(2)) increases to attain this maximum (or to its submaximal requirement), and even less to the kinetic features of the response following exercise. 2. Six, healthy, male volunteers (aged 22 to 58 years), each performed 13 exercise tests: initial ramp-incremental cycle ergometry to the limit of tolerance and subsequently, on different days, three bouts of square-wave exercise each at moderate, heavy, very heavy and severe intensities. Pulmonary gas exchange variables were determined breath by breath throughout exercise and recovery from the continuous monitoring of respired volumes (turbine) and gas concentrations (mass spectrometer). 3. For moderate exercise, the V(O(2)) kinetics were well described by a simple mono-exponential function, following a short cardiodynamic phase, with the on- and off-transients having similar time constants (tau(1)); i.e. tau(1,on) averaged 33 +/- 16 s (+/- S.D.) and tau(1,off) 29 +/- 6 s. 4. The on-transient V(O(2)) kinetics were more complex for heavy exercise. The inclusion of a second slow and delayed exponential component provided an adequate description of the response; i.e. tau(1,on) = 32 +/- 17 s and tau(2,on) = 170 +/- 49 s. The off-transient V(O(2)) kinetics, however, remained mono-exponential (tau(1,off) = 42 +/- 11 s). 5. For very heavy exercise, the on-transient V(O(2)) kinetics were also well described by a double exponential function (tau(1,on) = 34 +/- 11 s and tau(2,on) = 163 +/- 46 s). However, a double exponential, with no delay, was required to characterise the off-transient kinetics (i.e. tau(1,off) = 33 +/- 5 s and tau(2,off) = 460 +/- 123 s). 6. At the highest intensity (severe), the on-transient V(O(2)) kinetics reverted to a mono-exponential profile (tau(1,on) = 34 +/- 7 s), while the off-transient kinetics retained a two-component form (tau(1,off) = 35 +/- 11 s and tau(2,off) = 539 +/- 379 s). 7. We therefore conclude that the kinetics of V(O(2)) during dynamic muscular exercise are strikingly influenced by the exercise intensity, both with respect to model order and to dynamic asymmetries between the on- and off-transient responses.
Article
The Wingate Anaerobic Test (WAnT) is generally used to evaluate anaerobic cycling performance, but knowledge of the metabolic profile of WAnT is limited. Therefore the energetics of WAnT was analysed with respect to working efficiency and performance. A group of 11 male subjects [mean (SD), age 21.6 (3.8) years, height 178.6 (6.6) cm, body mass 82.2 (12.1) kg] performed a maximal incremental exercise test and a WAnT. Lactic and alactic anaerobic energy outputs were calculated from net lactate production and the fast component of the kinetics of post-exercise oxygen uptake. Aerobic metabolism was determined from oxygen uptake during exercise. The WAnT mean power of 683 (96.0) W resulted from a total energy output above the value at rest of 128.1 (23.2) kJ x 30 s(-1) [mean metabolic power=4.3 (0.8) kW] corresponding to a working efficiency of 16.2 (1.6)%. The WAnT working efficiency was lower (P < 0.01) than the corresponding value of 24.1 (1.7)% at 362 (41) W at the end of an incremental exercise test. During WAnT the fractions of the energy from aerobic, anaerobic alactic and lactic acid metabolism were 18.6 (2.5)%, 31.1 (4.6)%, and 50.3 (5.1)%, respectively. Energy from metabolism of anaerobic lactic acid explained 83% and 81% of the variance of WAnT peak and mean power, respectively. The results indicate firstly that WAnT requires the use of more anaerobically derived energy than previously estimated, secondly that anaerobic metabolism is dominated by glycolysis, thirdly that WAnT mechanical efficiency is lower than that found in aerobic exercise tests, and fourthly that the latter finding partly explains discrepancies between previously published and the present data about the metabolic profile of WAnT.
Article
It is speculated that anaerobic metabolism is the predominant source of energy in karate kumite. However, no experimental proof is currently available. The metabolic cost and fractions of aerobic and anaerobic energy of karate kumite fighting were investigated. Ten male nationally or internationally ranked karateka [means (SD) age 26.9 (3.8) years, height 1.80 (0.08) m, mass 77.2 (12.8) kg] performed two to four fights scheduled and judged like a championship. Oxygen uptake was measured continuously with a portable spirometric device. Blood lactate was determined immediately before, and minute by minute after, each fight. Aerobic, anaerobic alactic and anaerobic lactic energy were calculated from oxygen uptake during the fight ( VO(2)), the fast component of the post-fight oxygen uptake ( VO(2PCr)) above resting values and changes in blood lactate concentration (Net-BLC), respectively. Altogether, 36 fights lasting 267 (61) s were analysed. The referee's decisions caused an activity-to-break ratio of approximately 2:1. VO(2), VO(2PCr), and Net-BLC per fight were 165.3 (52.4) ml(.)kg(-1), 32.2 (7.2) ml(.)kg(-1)and 4.2 (1.9) mmol(.)l(-1); the overall energy cost above rest was 334.3 (86.3) kJ per fight. Fractions of aerobic, anaerobic alactic, and lactic energy sources were 77.8 (5.8)%, 16.0 (4.6)%, and 6.2 (2.4)%, respectively. The results indicate a high metabolic rate in karate kumite. However, the acyclic activity profile implies that aerobic metabolism is the predominant source of energy and there is anaerobic supplementation, mainly by high-energy phosphates.
Article
The purpose of this study was three-fold: (1) to characterise both the on- and off-transient oxygen uptake (V(.)O(2)) kinetics in endurance runners during moderate-intensity treadmill running; (2) to determine the degree of symmetry between on- and off-transients; and (3) to determine the reproducibility of V(.)O(2) kinetic parameters in endurance runners. Twelve endurance-trained runners [mean (SD) age 25.2 (4.7) years, body mass 70.1 (9.7) kg, height 179.5 (7.5) cm, ventilatory threshold (V(T)), 3,429 (389) ml.min(-1), maximal V(.)O(2) (V(.)O(2max)) 4,138 (625) ml.min(-1)] performed two multiple square-wave transition protocols on separate days. The protocol consisted of six (three transitions, 15 min rest, three transitions) square-wave transitions from walking at 4 km.h(-1) to running at a speed equivalent to 80% of the V(.)O(2) at the V(T) (80%V(T)). To determine the reproducibility, the protocol was repeated on a separate day (i.e. a test-retest design). Pulmonary gas-exchange was measured breath-by-breath. The V(.)O(2) data were modelled [from 20 s post-onset (or offset) of exercise] using non-linear least squares regression by a mono-exponential model, incorporating a time delay. The on- and off-transient time constants (tau(on) and tau(off)), mean response times (MRT(on) and MRT(off)) and amplitudes (A(on) and A(off)) were obtained from the model fit. On- and off transient kinetics were compared using paired t-tests. The reproducibility of each kinetic parameter was explored using statistical (paired t-tests) and non-statistical techniques [95% limits of agreement (LOA, including measurement error and systematic bias) and coefficient of variation (CV)]. It was found that the tau(on) [12.4 (1.9)] was significantly (P<0.001) shorter than tau(off) [24.5 (2.3) s]. Similarly, MRT(on) [27.1 (1.9) s] was shorter than MRT(off) [33.4 (2.2) s]. With respect to the reproducibility of the parameters, paired t-tests did not reveal significant differences between test 1 and test 2 for any on- or off-transient V(.)O(2) kinetic parameter (P>0.05). The LOA for tau(on) (1.9 s), tau(off) (2.3 s), MRT(on) (1.2 s), MRT(off) (3.2 s), A(on) (204 ml.min(-1)) and A(off) (198 ml.min(-1)) were narrow and acceptable. Furthermore, the measurement error (range, 4.3 to 15.1%) and CV (1.3 to 4.8%) all indicated good reproducibility. There was a tendency for tau(off) to be more reproducible than tau(on). However, MRT(on) was the most reproducible kinetic parameter. Overall, the results suggest that: (1) a multiple square-wave transition protocol can be used to characterise, reproducibly, both on- and off-transient V(.)O(2) kinetic parameters during treadmill running in runners; (2) the phase II time constant is independent of V(.)O(2) (max), and (3) asymmetry exists between on- and off transient V(.)O(2) kinetic parameters.
Article
To be able to identify a training induced change in a certain variable, it is necessary to know the background variation. In this study the coefficient of variation (total, between-subjects, within-subjects), the relative sources of variance (between-subjects and within-subjects), and the critical difference (within-subjects) were estimated in four categories of variables (performance and physiological variables, metabolic and hormonal variables, immunological variables, and mood state variables) in 15 moderately trained male runners measured on three different occasions over a period of 7 weeks. In the performance and physiological variables, 78.9 % of the variance was due to variation between subjects and they had the lowest critical difference (11.9 %). In contrast, the metabolic and hormonal variables had the highest critical difference (59.9 %) and 53.4 % of the variance was due to variations within subjects. The immunological and psychological variables had about two thirds of the variance arising from variation between subjects. However, the critical difference for the immunological variables was high (47.4 %), while it was relatively low for the psychological variables (26.8 %). The low critical difference and variation within subjects of the psychological and in particular the performance and physiological variables indicate that they may be beneficial as primary markers of training induced changes.
30–15 Intermittent Fitness Test: un nouveau test de terrain spécifiquement dédié aux joueurs de sport collectif pour la détermination d’une vitesse maximale aérobie intermittente
  • M Buchheit
  • Buchheit M
Buchheit M. 30-15 Intermittent Fitness Test: un nouveau test de terrain spécifiquement dédié aux joueurs de sport collectif pour la détermination d'une vitesse maximale aérobie intermittente. Approches du Handball. 2005;87:27-34.
Energetic profile of the basketball exercise simulation test in junior elite players
  • R Latzel
  • O Hoos
  • S Stier
  • Latzel R