scholarly journals Shorter constant work rate cycling tests as proxies for longer tests in highly trained cyclists

2021 ◽  
Author(s):  
Chantelle du Plessis ◽  
Mark Andrews ◽  
Lachlan Mitchell ◽  
Jodie Cochrane Wilkie ◽  
Trish King ◽  
...  
Keyword(s):  
Physiological Stress ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Rate ◽  
Mechanical Power ◽  
Maximal Power Output ◽  
Physiological Variables ◽  
Severe Intensity ◽  
Constant Work Rate ◽  
Test Outcomes

Severe-intensity constant work rate (CWR) cycling tests are useful for monitoring training progression and adaptation as they impose significant physiological and psychological strain and thus simulate the high-intensity competition environment. However, fatiguing tests require substantial recovery and may disrupt athlete training or competition preparation. Therefore, the development of a brief, minimally fatiguing test providing comparable information is desirable. Purpose : To determine whether physiological variables measured during, and functional decline in maximal power output immediately after, a 2-min CWR test can act as a proxy for 4-min test outcomes. Methods : Physiological stress was monitored and pre-to-post-CWR changes in 10-s sprint power computed (to estimate performance fatigability) during 2- and 4-min CWR tests in high-level cyclists. Results : The 2-min CWR test evoked a smaller decline in sprint mechanical power (32% vs. 47%, p <0.001), however both the physiological variables and sprint mechanical power were independently and strongly correlated between 2- and 4-min tests. Differences in V?O 2peak and blood lactate concentration in both CWR tests were strongly associated with the decline in sprint mechanical power. Conclusion : Physiological variables measured during, and the loss in sprint mechanical power measured after, a severe-intensity 2-min CWR test were less than in the 4-min test. Yet strong correlations between 2- and 4-min test outcomes indicated that the 2-min test can be used as a proxy for the longer test. Because shorter tests are less strenuous, they should have less impact on training and competition preparation and may therefore be more practically applicable within the elite performance environment.

Measurement of the maximum oxygen uptake V̇o2max: V̇o2peak is no longer acceptable

2017 ◽  
Vol 122 (4) ◽  
pp. 997-1002 ◽  
Author(s):  
David C. Poole ◽  
Andrew M. Jones
Keyword(s):  
Gas Exchange ◽  
Exercise Test ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Rate ◽  
Experimental Investigations ◽  
Maximal Heart Rate ◽  
Constant Work Rate ◽  
Rate Test ◽  
Oxidative Function

The maximum rate of O2 uptake (i.e., V̇o2max), as measured during large muscle mass exercise such as cycling or running, is widely considered to be the gold standard measurement of integrated cardiopulmonary-muscle oxidative function. The development of rapid-response gas analyzers, enabling measurement of breath-by-breath pulmonary gas exchange, has facilitated replacement of the discontinuous progressive maximal exercise test (that produced an unambiguous V̇o2-work rate plateau definitive for V̇o2max) with the rapidly incremented or ramp testing protocol. Although this is more suitable for clinical and experimental investigations and enables measurement of the gas exchange threshold, exercise efficiency, and V̇o2 kinetics, a V̇o2-work rate plateau is not an obligatory outcome. This shortcoming has led to investigators resorting to so-called secondary criteria such as respiratory exchange ratio, maximal heart rate, and/or maximal blood lactate concentration, the acceptable values of which may be selected arbitrarily and result in grossly inaccurate V̇o2max estimation. Whereas this may not be an overriding concern in young, healthy subjects with experience of performing exercise to volitional exhaustion, exercise test naïve subjects, patient populations, and less motivated subjects may stop exercising before their V̇o2max is reached. When V̇o2max is a or the criterion outcome of the investigation, this represents a major experimental design issue. This CORP presents the rationale for incorporation of a second, constant work rate test performed at ~110% of the work rate achieved on the initial ramp test to resolve the classic V̇o2-work rate plateau that is the unambiguous validation of V̇o2max. The broad utility of this procedure has been established for children, adults of varying fitness, obese individuals, and patient populations.

Effect of prior multiple-sprint exercise on pulmonary O2 uptake kinetics following the onset of perimaximal exercise

2004 ◽  
Vol 97 (4) ◽  
pp. 1227-1236 ◽  
Author(s):  
Daryl P. Wilkerson ◽  
Katrien Koppo ◽  
Thomas J. Barstow ◽  
Andrew M. Jones
Keyword(s):  
Time Constant ◽  
Near Infrared ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Primary Component ◽  
Work Rate ◽  
Cycle Exercise ◽  
Sprint Exercise ◽  
Exercise Condition ◽  
Constant Work Rate

We hypothesized that the metabolic acidosis resulting from the performance of multiple-sprint exercise would enhance muscle perfusion and result in a speeding of pulmonary oxygen uptake (V̇o2) kinetics during subsequent perimaximal-intensity constant work rate exercise, if O2 availability represented a limitation to V̇o2 kinetics in the control (i.e., no prior exercise) condition. On two occasions, seven healthy subjects completed two bouts of exhaustive cycle exercise at a work rate corresponding to ∼105% of the predetermined V̇o2 peak, separated by 3 × 30-s maximal sprint cycling and 15-min recovery (MAX1 and MAX2). Blood lactate concentration (means ± SD: MAX1: 1.3 ± 0.4 mM vs. MAX2: 7.7 ± 0.9 mM; P < 0.01) was significantly greater immediately before, and heart rate was significantly greater both before and during, perimaximal exercise when it was preceded by multiple-sprint exercise. Near-infrared spectroscopy also indicated that muscle blood volume and oxygenation were enhanced when perimaximal exercise was preceded by multiple-sprint exercise. However, the time constant describing the primary component (i.e., phase II) increase in V̇o2 was not significantly different between the two conditions (MAX1: 33.8 ± 5.5 s vs. MAX2: 33.2 ± 7.7 s). Rather, the asymptotic “gain” of the primary V̇o2 response was significantly increased by the performance of prior sprint exercise (MAX1: 8.1 ± 0.9 ml·min−1·W−1 vs. MAX2: 9.0 ± 0.7 ml·min−1·W−1; P < 0.05), such that V̇o2 was projecting to a higher “steady-state” amplitude with the same time constant. These data suggest that priming exercise, which apparently increases muscle O2 availability, does not influence the time constant of the primary-component V̇o2 response but does increase the amplitude to which V̇o2 may rise following the onset of perimaximal-intensity cycle exercise.

scholarly journals Steady-state $$\dot{V}{\text{O}}_{2}$$ above MLSS: evidence that critical speed better represents maximal metabolic steady state in well-trained runners

2021 ◽  
Author(s):  
Rebekah J. Nixon ◽  
Sascha H. Kranen ◽  
Anni Vanhatalo ◽  
Andrew M. Jones
Keyword(s):  
Steady State ◽  
Critical Speed ◽  
Lactate Concentration ◽  
Practical Interest ◽  
Blood Lactate Concentration ◽  
Distance Runners ◽  
Severe Intensity ◽  
The Stability ◽  
Trained Runners ◽  
Over Time

AbstractThe metabolic boundary separating the heavy-intensity and severe-intensity exercise domains is of scientific and practical interest but there is controversy concerning whether the maximal lactate steady state (MLSS) or critical power (synonymous with critical speed, CS) better represents this boundary. We measured the running speeds at MLSS and CS and investigated their ability to discriminate speeds at which $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 was stable over time from speeds at which a steady-state $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 could not be established. Ten well-trained male distance runners completed 9–12 constant-speed treadmill tests, including 3–5 runs of up to 30-min duration for the assessment of MLSS and at least 4 runs performed to the limit of tolerance for assessment of CS. The running speeds at CS and MLSS were significantly different (16.4 ± 1.3 vs. 15.2 ± 0.9 km/h, respectively; P < 0.001). Blood lactate concentration was higher and increased with time at a speed 0.5 km/h higher than MLSS compared to MLSS (P < 0.01); however, pulmonary $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 did not change significantly between 10 and 30 min at either MLSS or MLSS + 0.5 km/h. In contrast, $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 increased significantly over time and reached $$\dot{V}{\text{O}}_{2\,\,\max }$$ V ˙ O 2 max at end-exercise at a speed ~ 0.4 km/h above CS (P < 0.05) but remained stable at a speed ~ 0.5 km/h below CS. The stability of $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 at a speed exceeding MLSS suggests that MLSS underestimates the maximal metabolic steady state. These results indicate that CS more closely represents the maximal metabolic steady state when the latter is appropriately defined according to the ability to stabilise pulmonary $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 .

Lactate removal ability and graded exercise in humans

1990 ◽  
Vol 68 (3) ◽  
pp. 905-911 ◽  
Author(s):  
S. Oyono-Enguelle ◽  
J. Marbach ◽  
A. Heitz ◽  
C. Ott ◽  
M. Gartner ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Inverse Correlation ◽  
Continuous Model ◽  
Work Rate ◽  
Linear Relationships ◽  
Graded Exercise ◽  
Lactate Removal ◽  
The Individual

Venous lactate concentrations of nine athletes were recorded every 5 s before, during, and after graded exercise beginning at a work rate of 0 W with an increase of 50 W every 4th min. The continuous model proposed by Hughson et al. (J. Appl. Physiol. 62: 1975-1981, 1987) was well fitted with the individual blood lactate concentration vs. work rate curves obtained during exercise. Time courses of lactate concentrations during recovery were accurately described by a sum of two exponential functions. Significant direct linear relationships were found between the velocity constant (gamma 2 nu) of the slowly decreasing exponential term of the recovery curves and the times into the exercise when a lactate concentration of 2.5 mmol/l was reached. There was a significant inverse correlation between gamma 2 nu and the rate of lactate increase during the last step of the exercise. In terms of the functional meaning given to gamma 2 nu, these relationships indicate that the shift to higher work rates of the increase of the blood lactate concentration during graded exercise in fit or trained athletes, when compared with less fit or untrained ones, is associated with a higher ability to remove lactate during the recovery. The results suggest that the lactate removal ability plays an important role in the evolution pattern of blood lactate concentrations during graded exercise.

Exercise in Merino sheep dash the relationships between work intensity, endurance, anaerobic threshold and glucose metabolism

1991 ◽  
Vol 42 (4) ◽  
pp. 599 ◽  
Author(s):  
DW Pethick ◽  
CB Miller ◽  
NG Harman
Keyword(s):  
Glucose Metabolism ◽  
Anaerobic Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Respiratory Alkalosis ◽  
Work Rate ◽  
Glycerol Concentration ◽  
Work Intensity ◽  
Intensity Of Exercise

The effect of exercise intensity on (i) the ability of sheep to sustain exercise and (ii) glucose metabolism was investigated in fed non-pregnant adult Merino ewes. Five animals were prepared with cannulae to study the splanchnic tissues using the arteriovenous difference technique either at rest or during 8 levels of exercise: 3, 5, 7 and 9 km h-1 at either 0� or 9� incline. The anaerobic threshold, determined by elevation of blood lactate concentration or lactate/pyruvate ratio, occurred at a work rate of about 6-10 watts/kg body wt (7 km h-1 on 0� incline, 3 km h-1 on 9� incline). Only exercise well in excess of the anaerobic threshold resulted in ewes showing fatigue. Fatigue was not associated with carbohydrate depletion or lacticacidosis. Changes in the partial pressure of CO2 and the pH of blood indicated a marked respiratory alkalosis that was related to the severity of exercise, suggesting that thermoregulation may have been an important component of fatigue. Splanchnic blood flow declined when the intensity of exercise exceeded the anaerobic threshold; however, this did not compromise splanchnic function as assessed by oxygen and metabolite uptake. During exercise below the anaerobic threshold euglycemia was maintained while a pronounced hyperglycemia, that became more severe as the work rate increased, was found for exercise above the anaerobic threshold. The release of glucose by the liver increased significantly at all work rates and markedly so after the anaerobic threshold, such that the resultant hyperglycemia was consistent with an exaggerated hepatic glucose release due to 'feed forward' control. The contribution of lactate and glycerol to gluconeogenesis, assuming complete conversion, remained constant at 18-25% except at the highest work load where the contribution significantly declined to 9%. The decline was due to (i) saturation of hepatic lactate uptake and (ii) a failure for glycerol concentration and so uptake to increase beyond a work rate of 22 W kg-1. The requirement for gluconeogenic end products of digestion for animals grazed under extensive conditions would be 9-30% greater than for animals not exercising, depending upon the speed and inclination of exercise.

scholarly journals Prolonged static stretching causes acute, nonmetabolic fatigue and impairs exercise tolerance during severe-intensity cycling

2020 ◽  
Vol 45 (8) ◽  
pp. 902-910
Author(s):  
Alessandro L. Colosio ◽  
Massimo Teso ◽  
Silvia Pogliaghi
Keyword(s):  
Oxygen Consumption ◽  
Exercise Tolerance ◽  
Muscle Activation ◽  
Metabolic Response ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Time To Exhaustion ◽  
Static Stretching ◽  
Perception Of Effort ◽  
Severe Intensity

We tested the hypothesis that static stretching, an acute, nonmetabolic fatiguing intervention, reduces exercise tolerance by increasing muscle activation and affecting muscle bioenergetics during cycling in the “severe” intensity domain. Ten active men (age, 24 ± 2 years; body mass, 74 ± 11 kg; height, 176 ± 8 cm) participated in identical constant-load cycling tests of equal intensity, of which 2 tests were carried out under control conditions and 2 were done after stretching. This resulted in a 5% reduction of maximal isokinetic sprinting power output. We measured (i) oxygen consumption, (ii) electromyography, (iii) deoxyhemoglobin, (iv) blood lactate concentration; (v) time to exhaustion, and (vi) perception of effort. Finally, oxygen consumption and deoxyhemoglobin kinetics were determined. Force reduction following stretching was accompanied by augmented muscle excitation at a given workload (p = 0.025) and a significant reduction in time to exhaustion (p = 0.002). The time to peak oxygen consumption was reduced by stretching (p = 0.034), suggesting an influence of the increased muscle excitation on the oxygen consumption kinetics. Moreover, stretching was associated with a mismatch between O2 delivery and utilization during the isokinetic exercise, increased perception of effort, and blood lactate concentration; these observations are all consistent with an increased contribution of the glycolytic energy system to sustain the same absolute intensity. These results suggest a link between exercise intolerance and the decreased ability to produce force. Novelty We provided the first characterization of the effects of prolonged stretching on the metabolic response during severe cycling. Stretching reduced maximal force and augmented muscle activation, which in turn increased the metabolic response to sustain exercise.

Lactic acidosis as a facilitator of oxyhemoglobin dissociation during exercise

1994 ◽  
Vol 76 (4) ◽  
pp. 1462-1467 ◽  
Author(s):  
W. Stringer ◽  
K. Wasserman ◽  
R. Casaburi ◽  
J. Porszasz ◽  
K. Maehara ◽  
...  
Keyword(s):  
Lactic Acidosis ◽  
Femoral Vein ◽  
Lactate Concentration ◽  
Cycle Ergometer ◽  
Work Rate ◽  
Exercise Tests ◽  
Ergometer Exercise ◽  
Constant Work Rate ◽  
Slow Rise ◽  
Lactic Acidosis Threshold

The slow rise in O2 uptake (VO2), which has been shown to be linearly correlated with the increase in lactate concentration during heavy constant work rate exercise, led us to investigate the role of H+ from lactic acid in facilitating oxyhemoglobin (O2Hb) dissociation. We measured femoral venous PO2, O2Hb saturation, pH, PCO2, lactate, and standard HCO3- during increasing work rate and two constant work rate cycle ergometer exercise tests [below and above the lactic acidosis threshold (LAT)] in two groups of five healthy subjects. Mean end-exercise femoral vein blood and VO2 values for the below- and above-LAT square waves and the increasing work rate protocol were, respectively, PO2 of 19.8 +/- 2.1 (SD), 18.8 +/- 4.7, and 19.8 +/- 3.3 Torr; O2 saturation of 22.5 +/- 4.1, 13.8 +/- 4.2, and 18.5 +/- 6.3%; pH of 7.26 +/- 0.01, 7.02 +/- 0.11, and 7.09 +/- 0.07; lactate of 1.9 +/- 0.9, 11.0 +/- 3.8, and 8.3 +/- 2.9 mmol/l; and VO2 of 1.77 +/- 0.24, 3.36 +/- 0.4, and 3.91 +/- 0.68 l/min. End-exercise femoral vein PO2 did not differ statistically for the three protocols, whereas O2Hb saturation continued to decrease for work rates above LAT. We conclude that decreasing capillary PO2 accounted for most of the O2Hb dissociation during below-LAT exercise and that acidification of muscle capillary blood due to lactic acidosis accounted for virtually all of the O2Hb dissociation above LAT.

Continuous increase in blood lactate concentration during different ramp exercise protocols

1989 ◽  
Vol 66 (3) ◽  
pp. 1104-1107 ◽  
Author(s):  
M. E. Campbell ◽  
R. L. Hughson ◽  
H. J. Green
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Continuous Model ◽  
Work Rate ◽  
Transformation Model ◽  
Mean Square ◽  
Log Transformation ◽  
Ramp Exercise ◽  
The Mean

The applicability of a continuous model description of the blood lactate concentration [( La-]) vs. O2 uptake (VO2) relationship was studied in nine healthy male volunteers during three different ramp exercise protocols. The work rate was increased at either 8, 15, or 50 W/min. The continuous model for [La-] = a + b exp(cVO2) was compared statistically with a previously proposed log-log transformation model for the [La-] and VO2 variables. It was found that the mean square error was significantly less for the continuous as opposed to the log-log model (P less than 0.01) by analysis of variance pooled across all three ramp slopes. The mean square errors from the individual ramp slopes were also significantly less for the continuous model by paired t test (P less than 0.05). It was observed that the major contributor to the increased error of the log-log model was at VO2's at or above the intersection point (lactate threshold) of the two linear log-transformed segments. The log-log transformation does not appear to relate to any physiological process. The lactate slope index, taken as the point where the slope of the relationship between [La-] and VO2 (i.e., d[La-]/dVO2) equaled 1, occurred at a mean VO2 of 2.25 and 2.37 l/min for the 15- and 8-W/min ramp slopes, respectively, but at 2.76 l/min for the 50-W/min ramp (P less than 0.05). It is concluded that [La-] increases as a continuous function with respect to VO2 across a wide range of ramp work rate slopes.

scholarly journals High-Intensity Warm-Up Increases Anaerobic Energy Contribution during 100-m Sprint

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 198
Author(s):  
Seung-Bo Park ◽  
Da-Sol Park ◽  
Minjun Kim ◽  
Eunseok Lee ◽  
Doowon Lee ◽  
...  
Keyword(s):  
High Intensity ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Young Male ◽  
Time Trial ◽  
Energy System ◽  
Warm Up ◽  
Sprint Time ◽  
Physiological Variables ◽  
And Performance

This study aimed to evaluate the effects of warm-up intensity on energetic contribution and performance during a 100-m sprint. Ten young male sprinters performed 100-m sprints following both a high-intensity warm-up (HIW) and a low-intensity warm-up (LIW). Both the HIW and LIW were included in common baseline warm-ups and interventional warm-ups (eight 60-m runs, HIW; 60 to 95%, LIW; 40% alone). Blood lactate concentration [La−], time trial, and oxygen uptake (VO2) were measured. The different energy system contribution was calculated by using physiological variables. [La−1]Max following HIW was significantly higher than in LIW (11.86 ± 2.52 vs. 9.24 ± 1.61 mmol·L−1; p < 0.01, respectively). The 100-m sprint time trial was not significantly different between HIW and LIW (11.83 ± 0.57 vs. 12.10 ± 0.63 s; p > 0.05, respectively). The relative (%) phosphagen system contribution was higher in the HIW compared to the LIW (70 vs. 61%; p < 0.01, respectively). These results indicate that an HIW increases phosphagen and glycolytic system contributions as compared to an LIW for the 100-m sprint. Furthermore, an HIW prior to short-term intense exercise has no effect on a 100-m sprint time trial; however, it tends to improve times (decreased 100-m time trial; −0.27 s in HIW vs. LIW).

scholarly journals Diferencias en el OBLA en jugadoras de fútbol en relación a su posición en el campo de juego (Differences in OBLA in football players based on their field position)

Retos ◽  
2016 ◽  
pp. 58-61
Author(s):  
Jose E. Del Río Valdivia ◽  
Ciria Margarita Salazar ◽  
Julio Cuevas Romo ◽  
Adriana Isabel Andrade Sánchez ◽  
Pedro Julian Flores Moreno ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
P Value ◽  
Significance Level ◽  
Speed Test ◽  
Physiological Variables ◽  
Significant Difference ◽  
Speed Level ◽  
Field Position

La posición en el campo de juego en el fútbol, no obedece solo a un interés personal, sino que podría depender de variables fisiológicas individuales. El presente estudio determina el OBLA en las diferentes posiciones. La población del estudio fue integrada por 16 jugadoras universitarias de la modalidad soccer (4 por cada posición) evaluadas en una banda sin fin, con una prueba de velocidades crecientes. En cada velocidad utilizada se midió la concentración de lactato sanguíneo con un analizador portátil Accuntrend Lactate Plus. Para el análisis de los datos se propuso una fórmula matemática de interpolación entre las variables velocidad y concentración de lactato. Se encontró, una variación significativa del OBLA, en la muestra estudiada, dependiendo de la posición de juego (porteras, defensas, medio-campistas y delanteras). Utilizando la prueba de Kruskal-Wallis, con un nivel de significancia (α) del 5 %, en búsqueda de la relación entre el OBLA y la posición de las jugadoras, se obtuvo un p-valor de 0.004, por lo que no es posible aceptar la igualdad entre las poblaciones, por lo tanto, se puede afirmar que existe una diferencia estadística significativa cuando se compara el comienzo de acumulación de lactato en sangre (OBLA) con la posición en la que juegan las futbolistas. Los resultados demuestran que existen diferencias estadísticamente significativas entre los grupos de jugadoras de acuerdo a la posición que desempeñan en el campo de juego y a la concentración de lactato en sangre.Abstract. Choosing a field position in football may not depend only on personal interest, but also on individual physiological variables. The aim of the study is to determine the Onset of Blood Lactate Accumulation (OBLA) in the different field positions of football. The study sample was composed by 16 female players (four per position) evaluated using an increased speed test carried out on treadmill. At each speed level, blood lactate concentrations were measured with the portable analyzer Accuntrend Lactate Plus. A mathematical formula interpolating speed and lactate concentration was proposed for the analysis of the data obtained. A significant variation of OBLA was found in the participants, associated with playing position (goalkeepers, defenders, midfielders, and strikers). Setting the significance level (α) at 5%, a p-value of 0.004 was obtained using the Kruskal-Wallis test in order to study the relation between OBLA and players’ field position. This demonstrates that there is no equivalence among positions, at the same time as a statistically significant difference is shown when comparing OBLA with players’ field position. Results show that there are statistically significant differences between the groups of players based on their field position and on blood lactate concentration.

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