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Amino Acid Supplementation during Endurance Exercise. Dustin Joubert. Take Home Message. Should endurance athletes consume Amino Acids during exercise? No Unless… 1) Carbohydrate is unavailable 2) You are taking the 5 th grade exit exam afterwards. The Claims. Decrease central fatigue
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Amino Acid Supplementation during Endurance Exercise Dustin Joubert
Take Home Message • Should endurance athletes consume Amino Acids during exercise? No • Unless… 1) Carbohydrate is unavailable 2) You are taking the 5th grade exit exam afterwards
The Claims • Decrease central fatigue • Inhibit muscle tissue breakdown • Slow lactic acid build-up
Evidence – BCAAs & Central Fatigue • Theoretical mechanisms • Multiple parts, established animal models • Human studies less conclusive • BCAA supplementation • Beneficial if glycogen depleted, no carbohydrate • No effect when carbohydrate included • Except on post-test cognitive function (Hassmen, 1994) Bloomstrand (2001). Amino acids and central fatigue. Amino Acids. Blomstrand (2006). A role for branched-chain amino acids in reducing central fatigue. The Journal of Nutrition.
Evidence – Muscle Damage • Attenuated ↑ in creatinekinase/lactate dehydrogenase(Coombes, 2000) • 2 groups, 120 min cycling at 70% VO2max • 14d BCAA supplementation (7d before, 7d after) • Reduced CK/LDH from 2-hr to 5-d post-exercise • Controlled for normal dietary protein intake • No effect on ↑ in CK, performance, soreness (Knecthle, 2011) • 2 groups, 100 km ultra-marathon • Pre/during supplementation • Only compared pre-post samples • No Placebos
Evidence – Lactic Acid Production • Incremental cycling to exhaustion (Matsumoto, 2009) • Methods • BCAA vs. iso-caloric carbohydrate drink • 1 wk/pre-exercise supplementation • Randomized, double-blind, cross-over design • Results • No change in maximal exercise time or workload • No change in blood lactate at any workload • Increase in VO2max with BCAA • Lactate threshold higher workload, VO2, %VO2 w/BCAA • Meaningful?
Take Home Message • Should endurance athletes consume Amino Acids during exercise? No • Unless… 1) Carbohydrate is unavailable 2) You are taking the 5th grade exit exam afterwards