Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1439-6327
    Keywords: Key words Exercise ; 1H nuclear magnetic resonance ; 31P nuclear magnetic resonance ; Perfused muscle ; Lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated whether localized 1H nuclear magnetic resonance spectroscopy (NMRS) using stimulated echoes (STEAM) with a long mixing time (t m) allowed the suppression of the fat signal and detection of lactate in skeletal muscle. The 1H NMRS sequence was first validated in three isolated and perfused rabbit biceps brachii muscles. Spectra were obtained on a wide-bore spectrometer using a dual-tuned probe (1H and 31P). Death was simulated by ceasing the muscle perfusion, which allowed post-mortem changes to be followed. During and after the simulated death, changes in levels of pH and in content of energy-rich compounds were observed with 31P NMRS. Our results showed an inverse linear relationship between pH and lactate in each of the three rabbits (r = 0.93, P 〈 0.001; r = 0.92, P 〈 0.01; r = 0.89, P 〈 0.01) and a decrease in phosphocreatine and concomitant increase in lactate. We then investigated whether this sequence allowed repeated detection of lactate in human soleus muscle during the recovery between periods of intense exercise (force-velocity test, F-v test). Seven subjects mean age 25.1 (SEM 0.8) years participated in this study. Soleus muscle lactate was detected at rest and for 3 min 30 s of the 5-min recovery between periods using a 2.35-T 40-cm bore magnet spectrometer. Arm venous plasma lactate concentration was measured at rest, during the F-v test when the subject stopped pedalling (S1), and at the end of each 5-min recovery between periods (S2). Results showed that the venous plasma lactate concentration at S1 and S2 increased significantly from the beginning of the F-v test to peak anaerobic power (W an,peak) (P 〈 0.001). The spectra showed that muscle lactate resonance intensity rose markedly when W an,peak was achieved. The muscle lactate resonance intensity plotted as a percentage of the resting value increased significantly at W an,peak compared with submaximal braking forces (P 〈 0.05). We concluded from these results that localized 1H NMRS using STEAM with a long t m allows suppression of the fat signal and repeated detection of lactate on isolated perfused skeletal muscle in animals and between periods of intense exercise in humans.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...