This study aimed at assessing the sensitivity of both maximal lactate steady state (MLSS) and critical power (CP) in populations of different aerobic training status to ascertain whether CP is as sensitive as MLSS to a change in aerobic fitness. Seven untrained subjects (UT) (maximal oxygen uptake = 37.4 ± 6.5 mL·kg(-1)·min(-1)) and 7 endurance cyclists (T) (maximal oxygen uptake = 62.4 ± 5.2 mL·kg(-1)·min(-1)) performed an incremental test for maximal oxygen uptake estimation and several constant work rate tests for MLSS and CP determination. MLSS, whether expressed in mL·kg(-1)·min(-1) (T: 51.8 ± 5.7 vs. UT: 29.0 ± 6.1) or % maximal oxygen uptake (T: 83.1 ± 6.8 vs. UT: 77.1 ± 4.5), was significantly higher in the T group. CP expressed in mL·kg(-1)·min(-1) (T: 56.8 ± 5.1 vs. UT: 33.1 ± 6.3) was significantly higher in the T group as well but no difference was found when expressed in % maximal oxygen uptake (T: 91.1 ± 4.8 vs. UT: 88.3 ± 3.6). Whether expressed in absolute or relative values, MLSS is sensitive to aerobic training status and a good measure of aerobic endurance. Conversely, the improvement in CP with years of training is proportional to those of maximal oxygen uptake. Thus, CP might be less sensitive than MLSS for depicting an enhancement in aerobic fitness.

New Findings What is the central question of this study?What role do neuromuscular fatigue mechanisms play in resistance training‐induced adaptations of the impulse above end‐test torque (IET) after the training period? What is the main finding and its importance?IET and global and peripheral fatigue were increased after a short period of resistance training. Thus, resistance training‐induced adaptations in neuromuscular fatigue seem to contribute to enhanced IET after the training period. Abstract Short‐term resistance training has a positive influence on the curvature constant of the power–duration relationship (W′). The physiological mechanism of W′ enhancement after resistance training is unclear. This study aimed to determine whether one‐leg maximal isometric resistance training influences (1) impulse above end‐test torque (IET; an analogue of W′) during a 5 min all‐out isometric test; and (2) exercise tolerance (limit of tolerance, Tlim) and neuromuscular fatigue during severe exercise (i.e. above end‐test torque; ET). Sixteen healthy active males participated in a 3‐week unilateral knee extensor resistance‐training programme, and 10 matched subjects participated as controls. The subjects were instructed to ramp up to 100% of maximal voluntary contraction (MVC) over 1 s, hold it for 3 s, and relax. Each repetition had a 2 s interval (10) and each set, a 2 min interval (3). MVC (18.6%) and muscle thickness (12.8%) were significantly improved after training. Significantly greater global (i.e. reduced MVC, 43.2 ± 13.5% vs. 58.9 ± 6.9%) and peripheral (51.7 ± 13.6% vs. 57.3 ± 15.3%) fatigue, IET (26%) and Tlim (92%) were obtained after resistance training. Moreover, both global (r = 0.57, P < 0.05) and peripheral fatigue (r = 0.55, P < 0.05) accrued during severe exercise were associated with IET. However, echo intensity, which reflects muscle quality, ET and central fatigue remained unchanged throughout the training period. No significant changes in the control group for any variable were observed. Resistance training‐induced adaptations in muscle size and neuromuscular fatigue seem to contribute to enhanced IET and Tlim after the training period.

The purpose of this study was to determine both the independent and additive effects of prior heavy-intensity exercise and pacing strategies on the VO2 kinetics and performance during high-intensity exercise. Fourteen endurance cyclists (VO2max  = 62.8±8.5 mL.kg−1.min−1) volunteered to participate in the present study with the following protocols: 1) incremental test to determine lactate threshold and VO2max; 2) four maximal constant-load tests to estimate critical power; 3) six bouts of exercise, using a fast-start (FS), even-start (ES) or slow-start (SS) pacing strategy, with and without a preceding heavy-intensity exercise session (i.e., 90% critical power). In all conditions, the subjects completed an all-out sprint during the final 60 s of the test as a measure of the performance. For the control condition, the mean response time was significantly shorter (p<0.001) for FS (27±4 s) than for ES (32±5 s) and SS (32±6 s). After the prior exercise, the mean response time was not significantly different among the paced conditions (FS = 24±5 s; ES = 25±5 s; SS = 26±5 s). The end-sprint performance (i.e., mean power output) was only improved (∼3.2%, p<0.01) by prior exercise. Thus, in trained endurance cyclists, an FS pacing strategy does not magnify the positive effects of priming exercise on the overall VO2 kinetics and short-term high-intensity performance.

The purpose of this study was to analyze the effect of recovery type (passive vs. active) during prolonged intermittent exercises on the blood lactate concentration (MLSS) and work rate (MLSS(wint)) at maximal lactate steady state. Nineteen male trained cyclists were divided into 2 groups for the determination of MLSS(wint) using passive (maximal oxygen uptake = 58.1 ± 3.5 mL·kg(-1)·min(-1); N = 9) or active recovery (maximal oxygen uptake = 60.3 ± 9.0 mL·kg(-1)·min(-1); N = 10). They performed the following tests, on different days, on a cycle ergometer: (i) incremental test until exhaustion to determine maximal oxygen uptake; (ii) 2 to 3 continuous submaximal constant work rate tests (CWRT) for the determination of the work rate at continuous maximal lactate steady state (MLSS(wcont)); and (iii) 2 to 3 intermittent submaximal CWRT (7 × 4 min and 1 × 2 min, with 2-min recovery) with either passive or active recovery for the determination of MLSS(wint). MLSS(wint) was significantly higher when compared with MLSS(wcont) for both passive recovery (294.7 ± 32.2 vs. 258.7 ± 24.5 W, respectively) and active recovery groups (300.5 ± 23.9 vs. 273.2 ± 21.5 W, respectively). The percentage increments in MLSS(wint) were similar between conditions (passive = 13% vs. active = 10%). MLSS (mmol·L(-1)) was not significantly different between MLSS(wcont) and MLSS(wint) for either passive recovery (4.50 ± 2.10 vs. 5.61 ± 1.78, respectively) and active recovery (4.06 ± 1.49 vs. 4.91 ± 1.91, respectively) conditions. We can conclude that using a work/rest ratio of 2:1, MLSS(wint) was ∼10%-13% higher than MLSS(wcont), irrespective of the recovery type performed during prolonged intermittent exercises.

No abstract

RESUMoO principal objetivo deste estudo foi comparar a intensidade correspondente à máxima fase estável de lactato (MLSS) e a potência crítica (PC) durante o ciclismo em indivíduos bem treinados. Seis ciclistas do sexo masculino (25,5 ± 4,4 anos, 68,8 ± 3,0kg, 173,0 ± 4,0cm) realizaram em diferentes dias os seguintes testes: exercício incremental até a exaustão para a determinação do pico de consumo de oxigênio (VO 2 pico) e sua respectiva intensidade (IVO 2 pico); cinco a sete testes de carga constante para a determinação da MLSS e da PC; e um exercício até a exaustão na PC. A MLSS foi considerada com a maior intensidade de exercício onde a concentração de lactato não aumentou mais do que 1mM entre o 10 o e o 30 o min de exercício. Os valores individuais de potência (95, 100 e 110% IVO 2 pico) e seu respectivo tempo máximo de exercício (Tlim) foram ajustados a partir do modelo hiperbólico de dois parâmetros para a determinação da PC. Embora altamente correlacionadas (r = 0,99; p = 0,0001), a PC (313,5 ± 32,3W) foi significantemente maior do que a MLLS (287,0 ± 37,8W) (p = 0,0002). A diferença percentual da PC em relação à MLSS foi de 9,5 ± 3,1%. No exercício realizado na PC, embora tenha existido componente lento do VO 2 (CL = 400,8 ± 267,0 ml.min -1 ), o VO 2 pico não foi alcançado (91,1 ± 3,3 %). Com base nesses resultados pode-se concluir que a PC e a MLSS identificam diferentes intensidades de exercício, mesmo em atletas com elevada aptidão aeróbia. Entretanto, o percentual da diferença entre a MLLS e PC (9%) indica que relação entre esses dois índices pode depender da aptidão aeróbia. Durante o exercício realizado até a exaustão na PC, o CL que é desenvolvido não permite que o VO 2 pico seja alcançado.Palavras-chave: ciclismo, consumo de oxigênio, exercício aeróbio. aBStRaCtThe main objective of this study was to compare the intensity corresponding to the maximal lactate steady state (MLSS) and critical power (CP) in well-trained cyclists. Six male cyclists (25.5 ± 4.4 years, 68.8 ± 3.0 kg, 173.0 ± 4.0 cm) performed in different days the following tests: incremental exercise test until exhaustion to determine peak oxygen uptake (VO 2 peak) and its respective intensity (IVO 2 peak); five to seven constant workload tests to determine MLSS and CP and; one exhaustion test at CP. MLSS was defined as the highest workload at which blood lactate concentration did not increase by more than 1 mM between minutes 10 and 30 of the constant workload. Individual values for power-Tlim from the constant workload tests (95, 100 and 110% IVO 2 peak) were fit to the hyperbolic model of two-parameter to determine CP. Although highly correlated (r = 0.99; p = 0.0001), CP (313.5 + 32.3 W) was statistically higher than MLSS (287.0 + 37.8 W) (p = 0.0002). The percentual difference between CP and MLSS was 9.5 + 3.1 %. During exercise performed at CP, although a slow component of VO 2 has developed (SC = 400.8 + 267.0 ml.min -1 ), the VO 2 peak was not attained (91.1 + 3.3 %). Based on these results, it can be concluded that CP and...

The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.

Introduction: The determination of the exercise intensity domains has important implications for the aerobic training prescription and elaboration of experimental designs. Objective: The aim of this study was to analyze the effects of aerobic fitness level on the amplitude of the exercise intensity domains during cycling. Methods: Twelve cyclists (CYC), eleven runners (RUN) and eight untrained subjects (NT) underwent the following protocols on different days: 1) progressive test to determine lactate threshold (LT), maximal oxygen uptake (VO 2max ) and its corresponding intensity (IVO 2max); 2) three constant workload tests until exhaustion at 95, 100 and 110% IVO 2max to determine critical power (CP); 3) constant workload tests until exhaustion to determine the highest intensity at which VO 2max is reached (I sup ). Results: The amplitude of the moderate domain was similar between CYC (52 ± 8%) and RUN (47 ± 4%) and significantly greater in CYC when compared with NT (41 ± 7%). The heavy domain was significantly smaller in CYC (17 ± 6%) when compared with RUN (27 ± 6%) and NT (27 ± 9%). In relation to severe domain, there were no significant differences among CYC (31 ± 7%), RUN (26 ± 5%) and NT (31 ± 7%). Conclusion: It can be concluded that the heavy domain is more sensitive to changes determined by the aerobic fitness level; there is a need hence to observe the training specificity, when high level of physiological adaptation is aimed..