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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 40 (1991), S. 279-282 
    ISSN: 1432-1041
    Keywords: Caffeine ; Exercise ; Pharmacokinetics ; heavy coffe intake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of moderate exercise on the kinetics of caffeine in 12 healthy volunteers-6 heavy coffee drinkers (HD) and 6 light coffee drinkers (LD) has been studied. Kinetics at Rest was measured first (R): the subjects remained at rest for 8 h after a single 250 mg dose of caffeine. One week later, the Exercise Kinetics (E) was measured under the same conditions, but with the subjects performing moderate exercise (30% of VO 2 max) during the first hour of the study. Exercise raised the maximal plasma caffeine concentrations (R: 7.28; E: 10.45) and reduced both the half-life (R 3.99 h; E 2.29 h) and the volume of distribution (R 371; E 20.91). Both during exercise and at rest, HD had a greater half-life elimination and volume of distribution than LD. The results suggest potentiation of the effects of caffeine during exercise and an increase in its distribution due to regular heavy coffee intake.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 65 (1992), S. 188-191 
    ISSN: 1439-6327
    Keywords: Force-velocity exercise test ; Maximal anaerobic power ; Caffeine ; Lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to specify the effects of caffeine on maximal anaerobic power (W max). A group of 14 subjects ingested caffeine (250 mg) or placebo in random double-blind order. TheW max was determined using a force-velocity exercise test. In addition, we measured blood lactate concentration for each load at the end of pedalling and after 5 min of recovery. We observed that caffeine increasedW max [964 (SEM 65.77) W with caffeine vs 903.7 (SEM 52.62) W with placebo;P〈0.02] and blood lactate concentration both at the end of pedalling [8.36 (SEM 0.95) mmol · l−1 with caffeine vs 7.17 (SEM 0.53) mmol · l−1 with placebo;P〈0.011 and after 5 min of recovery [10.23 (SEM 0.97) mmol · l−1 with caffeine vs 8.35 (SEM 0.66) mmol · l−1 with placebo;P〈0.04]. The quotient lactate concentration/power (mmol · l−1 · W−1) also increased with caffeine at the end of pedalling [7.6 · 10−3 (SEM 3.82 · 10−5) vs 6.85 · 10−3 (SEM 3.01 · 10−5);P〈0.01] and after 5 min of recovery [9.82·10−3 (SEM 4.28 · 10−5) vs 8.84 · 10−3 (SEM 3.58 · 10−5);P〈0.02]. We concluded that caffeine increased bothW max and blood lactate concentration.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1439-6327
    Keywords: 2-Chloropropionate ; Force-velocity test ; Anaerobic power ; Venous plasma lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the effects of a stimulation of pyruvate dehydrogenase (PDH) activity induced by 2-chloropropionate (2-CP) on venous plasma lactate concentration and peak anaerobic power (W an, peak) during periods (6 s) of incremental intense exercise, i.e. a force-velocity (F-ν) test known to induce a marked accumulation of lactate in the blood. TheF-ν test was performed twice by six subjects according to a double-blind randomized crossover protocol: once with placebo and once with 2-CP (43 mg · kg−1 body mass). Blood samples were taken at ingestion of the drug, at 10, 20, and 40 Min into the pretest period, at the end of each period of intense exercise, at the end of each 5-min recovery period, and after completion of theF-ν test at 5, 10, 15, and 30 min. During theF-ν test, venous plasma lactate concentrations with both placebo and 2-CP increased significantly when measured at the end of each period of intense exercise (F = 33.5,P 〈 0.001), and each 5-min recovery period (F = 24.6,P 〈 0.001). Venous plasma lactate concentrations were significantly lower with 2-CP at the end of each recovery period (P 〈 0.01), especially for high braking forces, i.e. 8 kg (P 〈 0.05), 9 kg (P 〈 0.02), and maximal braking force (P 〈 0.05). After completion of theF-ν test, venous plasma lactate concentrations were also significantly lower with 2-CP (P 〈 0.001). The percentage of lactate decrease between 5- and 30-min recovery was significantly higher with 2-CP than with the placebo [59 (SEM 4)% vs 44.6 (SEM 5.5)%,P 〈 0.05]. Furthermore,W an, peak was significantly higher with 2-CP than with the placebo [1016 (SEM 60) W vs 957 (SEM 55) W,P 〈 0.05]. In conclusion, PDH activation by 2-CP attenuated the increase in venous plasma lactate concentration during theF-ν test. Ingestion of 2-CP led to an increasedW an, peak.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 70 (1995), S. 58-65 
    ISSN: 1439-6327
    Keywords: Oxygen uptake ; Lactate ; Wingate test ; Runners
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake ( $$\dot V{\text{O}}_{\text{2}} $$ ) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power ( $$\dot W$$ ) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic ( $$\dot W$$ aer,ind,16%,25%) and anaerobic ( $$\dot W$$ an,ind,16%,25%) processes. Peak anaerobic power ( $$\dot W$$ an,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure ( $$\dot W$$ aer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater $$\dot V{\text{O}}_{\text{2}} $$ than the sprinters (P 〈 0.001), who had significantly greater venous plasma lactate concentrations (P 〈 0.001). Moreover, $$\dot W$$ aer,ind,16%,25% were also significantly higher (P 〈 0.05) in the middle-distance runners [ $$\dot W$$ aer,ind 45 (SEM 4) % vs 28 (SEM 2) %; $$\dot W$$ aer,16% 30 (SEM 3) % vs 19 (SEM 2) %; $$\dot W$$ aer,25% 46 (SEM 3) % vs 29 (SEM 2)%]; $$\dot W$$ an,ind,16%,25% in the sprint runners (P 〈 0.05) [ $$\dot W$$ an,ind 72 (SEM 3) % vs 55 (SEM 4) %; $$\dot W$$ an,16% 81 (SEM 2) % vs 70 (SEM 3) %; $$\dot W$$ an,25% 71 (SEM 2) % vs 54 (SEM 3) %]. The $$\dot W$$ aer,ind/ $$\dot W$$ aer,peak and $$\dot W$$ × $$\dot W$$ an,ind/ $$\dot W$$ an,peak ratios, however, were not significantly different between the two groups of athletes. These results would indicate that the sprinters and middle-distance runners used preferentially a metabolic system according to their speciality. Nevertheless, under the conditions of its experiment, they seemed to rely on the same percentage of both peak anaerobic and peak aerobic performance for a given exercise task.
    Type of Medium: Electronic Resource
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