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.

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.

scholarly journals Effect of pedal rate on primary and slow-component oxygen uptake responses during heavy-cycle exercise

2003 ◽  
Vol 94 (4) ◽  
pp. 1501-1507 ◽  
Author(s):  
Jamie S. M. Pringle ◽  
Jonathan H. Doust ◽  
Helen Carter ◽  
Keith Tolfrey ◽  
Andrew M. Jones
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Motor Units ◽  
Primary Component ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
Pedal Rate

We hypothesized that a higher pedal rate (assumed to result in a greater proportional contribution of type II motor units) would be associated with an increased amplitude of the O2 uptake (V˙o 2) slow component during heavy-cycle exercise. Ten subjects (mean ± SD, age 26 ± 4 yr, body mass 71.5 ± 7.9 kg) completed a series of square-wave transitions to heavy exercise at pedal rates of 35, 75, and 115 rpm. The exercise power output was set at 50% of the difference between the pedal rate-specific ventilatory threshold and peakV˙o 2, and the baseline power output was adjusted to account for differences in the O2 cost of unloaded pedaling. The gain of the V˙o 2primary component was significantly higher at 35 rpm compared with 75 and 115 rpm (mean ± SE, 10.6 ± 0.3, 9.5 ± 0.2, and 8.9 ± 0.4 ml · min−1 · W−1, respectively; P < 0.05). The amplitude of theV˙o 2 slow component was significantly greater at 115 rpm (328 ± 29 ml/min) compared with 35 rpm (109 ± 30 ml/min) and 75 rpm (202 ± 38 ml/min) ( P < 0.05). There were no significant differences in the time constants or time delays associated with the primary and slow components across the pedal rates. The change in blood lactate concentration was significantly greater at 115 rpm (3.7 ± 0.2 mM) and 75 rpm (2.8 ± 0.3 mM) compared with 35 rpm (1.7 ± 0.4 mM) ( P < 0.05). These data indicate that pedal rate influences V˙o 2 kinetics during heavy exercise at the same relative intensity, presumably by altering motor unit recruitment patterns.

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.

Which common NIRS variable reflects muscle estimated lactate threshold most closely?

2006 ◽  
Vol 31 (5) ◽  
pp. 612-620 ◽  
Author(s):  
Lixin Wang ◽  
Takahiro Yoshikawa ◽  
Taketaka Hara ◽  
Hayato Nakao ◽  
Takashi Suzuki ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Oxygenation Index ◽  
Muscle Lactate ◽  
Tissue Oxygenation Index ◽  
The Mean ◽  
Tissue Hemoglobin

Various near-infrared spectroscopy (NIRS) variables have been used to estimate muscle lactate threshold (LT), but no study has determined which common NIRS variable best reflects muscle estimated LT. Establishing the inflection point of 2 regression lines for deoxyhaemoglobin (ΔHHbi.p.), oxyhaemoglobin (ΔO2Hbi.p.), and tissue oxygenation index (TOIi.p.), as well as for blood lactate concentration, we then investigated the relationships between NIRS variables and ventilatory threshold (VT), LT, or maximal tissue hemoglobin index (nTHImax) during incremental cycling exercise. ΔHHbi.p. and TOIi.p. could be determined for all 15 subjects, but ΔO2Hbi.p. was determined for only 11 subjects. The mean absolute values for the 2 measurable slopes of the 2 continuous linear regression lines exhibited increased changes in 3 NIRS variables. The workload and VO2 at ΔO2Hbi.p. and nTHImax were greater than those at VT, LT, ΔHHbi.p., and TOIi.p.. For workload and VO2, ΔHHbi.p. was correlated with VT and LT, whereas ΔO2Hbi.p. was correlated with nTHImax, and TOIi.p. with VT and nTHImax. These findings indicate that ΔO2Hb strongly corresponds with local perfusion, and TOI corresponds with both local perfusion and deoxygenation, but that ΔHHb can exactly determine deoxygenation changes and reflect O2 metabolic dynamics. The finding of strongest correlations between ΔHHb and VT or LT indicates that ΔHHb is the best variable for muscle LT estimation.

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.

scholarly journals Time required for the restoration of normal heavy exercise V̇o2 kinetics following prior heavy exercise

2006 ◽  
Vol 101 (5) ◽  
pp. 1320-1327 ◽  
Author(s):  
Mark Burnley ◽  
Jonathan H. Doust ◽  
Andrew M. Jones
Keyword(s):  
Blood Lactate ◽  
Priming Effect ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
V̇o2 Kinetics ◽  
Time Required ◽  
Male Subjects

Prior heavy exercise markedly alters the O2 uptake (V̇o2) response to subsequent heavy exercise. However, the time required for V̇o2 to return to its normal profile following prior heavy exercise is not known. Therefore, we examined the V̇o2 responses to repeated bouts of heavy exercise separated by five different recovery durations. On separate occasions, nine male subjects completed two 6-min bouts of heavy cycle exercise separated by 10, 20, 30, 45, or 60 min of passive recovery. The second-by-second V̇o2 responses were modeled using nonlinear regression. Prior heavy exercise had no effect on the primary V̇o2 time constant (from 25.9 ± 4.7 s to 23.9 ± 8.8 s after 10 min of recovery; P = 0.338), but it increased the primary V̇o2 amplitude (from 2.42 ± 0.39 to 2.53 ± 0.41 l/min after 10 min of recovery; P = 0.001) and reduced the V̇o2 slow component (from 0.44 ± 0.13 to 0.21 ± 0.12 l/min after 10 min of recovery; P < 0.001). The increased primary amplitude was also evident after 20–45 min, but not after 60 min, of recovery. The increase in the primary V̇o2 amplitude was accompanied by an increased baseline blood lactate concentration (to 5.1 ± 1.0 mM after 10 min of recovery; P < 0.001). Baseline blood lactate concentration was still elevated after 20–60 min of recovery. The priming effect of prior heavy exercise on the V̇o2 response persists for at least 45 min, although the mechanism underpinning the effect remains obscure.

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.

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.

Spatial heterogeneity of quadriceps muscle deoxygenation kinetics during cycle exercise

2007 ◽  
Vol 103 (6) ◽  
pp. 2049-2056 ◽  
Author(s):  
Shunsaku Koga ◽  
David C. Poole ◽  
Leonard F. Ferreira ◽  
Brian J. Whipp ◽  
Narihiko Kondo ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Optical Fibers ◽  
Near Infrared ◽  
Quadriceps Muscle ◽  
Primary Component ◽  
Phase 2 ◽  
Cycle Exercise ◽  
Muscle Deoxygenation ◽  
Spatially Inhomogeneous ◽  
Exercise Onset

To test the hypothesis that, during exercise, substantial heterogeneity of muscle hemoglobin and myoglobin deoxygenation [deoxy(Hb + Mb)] dynamics exists and to determine whether such heterogeneity is associated with the speed of pulmonary O2 uptake (pV̇o2) kinetics, we adapted multi-optical fibers near-infrared spectroscopy (NIRS) to characterize the spatial distribution of muscle deoxygenation kinetics at exercise onset. Seven subjects performed cycle exercise transitions from unloaded to moderate [<gas exchange threshold (GET)] and heavy (>GET) work rates and the relative changes in deoxy(Hb + Mb), at 10 sites in the quadriceps, were sampled by NIRS. At exercise onset, the time delays in muscle deoxy(Hb + Mb) were spatially inhomogeneous [intersite coefficient of variation (CV), 3∼56% for <GET, 2∼21% for >GET]. The primary component kinetics (time constant) of muscle deoxy(Hb + Mb) reflecting increased O2 extraction were also spatially inhomogeneous (intersite CV, 6∼48% for <GET, 7∼47% for >GET) and faster (P < 0.05) than those of phase 2 pV̇o2. However, the degree of dynamic intersite heterogeneity in muscle deoxygenation did not correlate significantly with phase 2 pV̇o2 kinetics. In conclusion, the dynamics of quadriceps microvascular oxygenation demonstrates substantial spatial heterogeneity that must arise from disparities in the relative kinetics of V̇o2 and O2 delivery increase across the regions sampled.

Effect of prior exercise on pulmonary O2 uptake and estimated muscle capillary blood flow kinetics during moderate-intensity field running in men

2009 ◽  
Vol 107 (2) ◽  
pp. 460-470 ◽  
Author(s):  
Martin Buchheit ◽  
Paul B. Laursen ◽  
Said Ahmaidi
Keyword(s):  
Blood Flow ◽  
Response Time ◽  
Near Infrared ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Moderate Intensity ◽  
Prior Exercise ◽  
Intensity Field

The effect of prior exercise on pulmonary O2 uptake (V̇o2 p) and estimated muscle capillary blood flow (Q̇m) kinetics during moderate-intensity, field-based running was examined in 14 young adult men, presenting with either moderately fast (16 s < τV̇o2 p < 30 s; MFK) or very fast V̇o2 p kinetics (τV̇o2 p < 16 s; VFK) (i.e., primary time constant, τV̇o2 p). On four occasions, participants completed a square-wave protocol involving two bouts of running at 90–95% of estimated lactate threshold (Mod1 and Mod2), separated by 2 min of repeated supramaximal sprinting. V̇o2 p was measured breath by breath, heart rate (HR) beat to beat, and vastus lateralis oxygenation {deoxy-hemoglobin/myoglobin concentration (deoxy-[Hb+Mb])} using near-infrared spectroscopy. Mean response time of Q̇m (Q̇m MRT) was estimated by rearranging the Fick equation, using V̇o2 p and deoxy-[Hb+Mb] as proxies of muscle O2 uptake (V̇o2) and arteriovenous difference, respectively. HR, blood lactate concentration, total hemoglobin, and Q̇m were elevated before Mod2 compared with Mod1 (all P < 0.05). τV̇o2 p was shorter in VFK compared with MFK during Mod1 (13.1 ± 1.8 vs. 21.0 ± 2.5 s, P < 0.01), but not in Mod2 (12.9 ± 1.5 vs. 13.7 ± 3.8 s, P = 1.0). Q̇m MRT was shorter in VFK compared with MFK in Mod1 (8.8 ± 1.9 vs. 17.0 ± 3.4 s, P < 0.01), but not in Mod2 (10.1 ± 1.8 vs. 10.5 ± 3.5 s, P = 1.0). During Mod2, HR kinetics were slowed, whereas mean deoxy-[Hb+Mb] response time was unchanged. The difference in τV̇o2 p between Mod1 and Mod2 was related to Q̇m MRT measured at Mod1 ( r = 0.71, P < 0.01). Present results suggest that local O2 delivery (i.e., Q̇m) may be a factor contributing to the V̇o2 kinetic during the onset of moderate-intensity, field-based running exercise, at least in subjects exhibiting moderately fast V̇o2 kinetics.

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