Improved 2000-Meter Rowing Performance in Competitive Oarswomen after Caffeine Ingestion

2000 ◽  
Vol 10 (4) ◽  
pp. 464-475 ◽  
Author(s):  
Megan E. Anderson ◽  
Clinton R. Bruce ◽  
Steve F. Fraser ◽  
Nigel K. Stepto ◽  
Rudi Klein ◽  
...  

Eight competitive oarswomen (age, 22 ± 3 years; mass, 64.4 ± 3.8 kg) performed three simulated 2,000-m time trials on a rowing ergometer. The trials, which were preceded by a 24-hour dietary and training control and 72 hours of caffeine abstinence, were condueted 1 hour after ingesting caffeine (6 or 9 mg kg ’ body mass) or placebo. Plasma free fatty acid concentrations before exercise were higher with caffeine than placebo (0.67 ± 0.34 vs. 0.72 ± 0.36 vs. 0.30±0.10 mM for 6 and 9 mg · kg−1; caffeine and placebo, respectively; p <.05). Performance lime improved 0.7% (95% confidence interval [Cf] 0 to 1.5%) with 6 mg kg−1 caffeine and 1.3$ (95% CI 0.5 to 2.0%) with 9 mg · kg−1 caffeine. The first 500 m of the 2,000 m was faster with the higher caffeine dose compared with placebo or the lower dose (1.53 ± 0.52 vs. 1.55 ± 0.62 and 1.56 ± 0.43 min; p = .02). We concluded that caffeine produces a worthwhile enhancement of performance in a controlled laboratory setting, primarily by improving the first 500 m of a 2,000-m row.

1980 ◽  
Vol 49 (1) ◽  
pp. 102-106 ◽  
Author(s):  
K. M. Baldwin ◽  
A. M. Hooker ◽  
R. E. Herrick ◽  
L. F. Schrader

This study was undertaken to determine the effects of propylthiouracil-induced thyroid deficiency on a) the capacity of muscle homogenates to oxidize [2-14C]pyruvate and [U-14C]palmitate and b) glycogen depletion during exercise in liver and in fast-oxidative-glycogenolytic (FOG), fast-glycogenolytic (FG), and slow-oxidative (SO) muscle. Relative to the rates for normal rats, oxidation with pyruvate was reduced by 53, 68, and 58%, and palmitate by 40, 50, and 48% in FOG, FG, and SO muscle, respectively (P less than 0.05). Normal rats ran longer than thyroid-deficient rats at 26.7 m/min (87 ± 8 vs. 37 ± 5 min). After 40 min of running (22 m/min), the amount of glycogen consumed in normal FOG, FG, and SO muscle and in liver amounted to only 23, 12, 66, and 52%, respectively, of that for their thyroid-deficient counterparts. Also, normal rats maintained higher plasma free fatty acid levels than thyroid-deficient rats during both rest and exercise (P less than 0.05). These findings suggest that thyroid deficiency causes a reduced potential for FFA utilization in skeletal muscle that enhances its consumption of glycogen, thereby limiting endurance capacity.


2012 ◽  
Vol 7 (2) ◽  
pp. 152-160 ◽  
Author(s):  
Amelia J. Carr ◽  
Gary J. Slater ◽  
Christopher J. Gore ◽  
Brian Dawson ◽  
Louise M. Burke

Purpose:The aim of this study was to determine the effect and reliability of acute and chronic sodium bicarbonate ingestion for 2000-m rowing ergometer performance (watts) and blood bicarbonate concentration [HCO3−].Methods:In a crossover study, 7 well-trained rowers performed paired 2000-m rowing ergometer trials under 3 double-blinded conditions: (1) 0.3 grams per kilogram of body mass (g/kg BM) acute bicarbonate; (2) 0.5 g/kg BM daily chronic bicarbonate for 3 d; and (3) calcium carbonate placebo, in semi-counterbalanced order. For 2000-m performance and [HCO3−], we examined differences in effects between conditions via pairwise comparisons, with differences interpreted in relation to the likelihood of exceeding smallest worthwhile change thresholds for each variable. We also calculated the within-subject variation (percent typical error).Results:There were only trivial differences in 2000-m performance between placebo (277 ± 60 W), acute bicarbonate (280 ± 65 W) and chronic bicarbonate (282 ± 65 W); however, [HCO3−] was substantially greater after acute bicarbonate, than with chronic loading and placebo. Typical error for 2000-m mean power was 2.1% (90% confidence interval 1.4 to 4.0%) for acute bicarbonate, 3.6% (2.5 to 7.0%) for chronic bicarbonate, and 1.6% (1.1 to 3.0%) for placebo. Postsupplementation [HCO3−] typical error was 7.3% (5.0 to 14.5%) for acute bicarbonate, 2.9% (2.0 to 5.7%) for chronic bicarbonate and 6.0% (1.4 to 11.9%) for placebo.Conclusion:Performance in 2000-m rowing ergometer trials may not substantially improve after acute or chronic bicarbonate loading. However, performances will be reliable with both acute and chronic bicarbonate loading protocols.


1971 ◽  
Vol 49 (5) ◽  
pp. 394-398 ◽  
Author(s):  
W. D. Wagner ◽  
R. A. Peterson ◽  
R. J. Cenedella

Plasma free fatty acid (FFA) levels and the effects of prostaglandin E1 (PGE1) were studied in cold-acclimated and cold-exposed chickens and compared to controls. Chickens cold-acclimated at 4–7 or 8–11 °C for 4 weeks had significantly elevated plasma FFA when compared to the controls at 19–21 °C. Although PGE1 had no effect on the basal level of FFA of controls, a significantly lower plasma FFA was seen after injection of either 10 or 30 μg PGE1/kg in cold-acclimated chickens. Chickens cold-exposed to 2–3 °C for 4 h demonstrated significant elevations of plasma FFA when compared to controls. Only 30 μg PGE1/kg significantly depressed the plasma FFA in the cold-exposed birds. No inhibition of basal FFA release was seen in control animals. From these experiments, it is concluded that chickens mobilize FFA extensively under cold-exposure and that this stimulated lipolysis is inhibited by PGE1.


1994 ◽  
Vol 26 (Supplement) ◽  
pp. S72
Author(s):  
C. A. Raguso ◽  
A. R. Coggan ◽  
L. S. Sidossis ◽  
A. Gastaldelli ◽  
R. R. Wolfe

1999 ◽  
Vol 40 (6) ◽  
pp. 1155-1169
Author(s):  
Nicholas D. Oakes ◽  
Ann Kjellstedt ◽  
Gun-Britt Forsberg ◽  
Tony Clementz ◽  
Germán Camejo ◽  
...  

PEDIATRICS ◽  
1966 ◽  
Vol 37 (4) ◽  
pp. 597-604
Author(s):  
Doman K. Keele ◽  
Jacob L. Kay

Simultaneous plasma free fatty acid (FFA) and blood sugar levels were determined for fasting newborn infants during the first 24 hours of life, for their cord bloods, and for their mothers at delivery. The following observations were made. In control infants the mean FFA level rose about three times the cord level after birth and was accompanied by a 25% drop in the mean blood sugar level. Thereafter, the mean blood sugar level remained relatively constant, but the mean FFA level varied from 2½ to 3 times the cord level. There was no significant correlation between the length of maternal fasting prior to delivery and the infant FFA level; there was, however a significant negative correlation between the length of maternal fasting prior to delivery and the infant blood sugar level at 24 hours of age. High FFA levels occurred in the infants of obese mothers and low levels were observed in infants with delayed respirations, in infants of preeclamptic mothers, and in infants of diabetic mothers.


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