Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km
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Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km. / Madsen, Klavs; MacLean, David A; Kiens, Bente; Christensen, Dirk.
I: Journal of Applied Physiology, Bind 81, Nr. 6, 12.1996, s. 2644-2650.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km
AU - Madsen, Klavs
AU - MacLean, David A
AU - Kiens, Bente
AU - Christensen, Dirk
PY - 1996/12
Y1 - 1996/12
N2 - This study was undertaken to determine the effects of ingesting either glucose (trial G) or glucose plus branched-chain amino acids (BCAA: trial B), compared with placebo (trial P), during prolonged exercise. Nine well-trained cyclists with a maximal oxygen uptake of 63.1 +/- 1.5 ml O2. min-1.kg-1 performed three laboratory trials consisting of 100 km of cycling separated by 7 days between each trial. During these trials, the subjects were encouraged to complete the 100 km as fast as possible on their own bicycles connected to a magnetic brake. No differences in performance times were observed between the three trials (160.1 +/- 4.1, 157.2 +/- 4.5, and 159.8 +/- 3.7 min, respectively). In trial B, plasma BCAA levels increased from 339 +/- 28 microM at rest to 1,026 +/- 62 microM after exercise (P < 0.01). Plasma ammonia concentrations increased during the entire exercise period for all three trials and were significantly higher in trial B compared with trials G and P (P < 0.05). The respiratory exchange ratio was similar in the three trials during the first 90 min of exercise; thereafter, it tended to drop more in trial P than in trials G and B. These data suggest that neither glucose nor glucose plus BCAA ingestion during 100 km of cycling enhance performance in well-trained cyclists.
AB - This study was undertaken to determine the effects of ingesting either glucose (trial G) or glucose plus branched-chain amino acids (BCAA: trial B), compared with placebo (trial P), during prolonged exercise. Nine well-trained cyclists with a maximal oxygen uptake of 63.1 +/- 1.5 ml O2. min-1.kg-1 performed three laboratory trials consisting of 100 km of cycling separated by 7 days between each trial. During these trials, the subjects were encouraged to complete the 100 km as fast as possible on their own bicycles connected to a magnetic brake. No differences in performance times were observed between the three trials (160.1 +/- 4.1, 157.2 +/- 4.5, and 159.8 +/- 3.7 min, respectively). In trial B, plasma BCAA levels increased from 339 +/- 28 microM at rest to 1,026 +/- 62 microM after exercise (P < 0.01). Plasma ammonia concentrations increased during the entire exercise period for all three trials and were significantly higher in trial B compared with trials G and P (P < 0.05). The respiratory exchange ratio was similar in the three trials during the first 90 min of exercise; thereafter, it tended to drop more in trial P than in trials G and B. These data suggest that neither glucose nor glucose plus BCAA ingestion during 100 km of cycling enhance performance in well-trained cyclists.
M3 - Journal article
VL - 81
SP - 2644
EP - 2650
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -
ID: 33596392