¿Energy substrate or protein synthesis?
In case of protein synthesis, Does this happen at the expense of AMPK?
Is better intake EAA´s because you have all essential aminoacids for building the proteins that your body needs in that moment.
BCAA's may be useful as both an energy substrate and beneficial for protein synthesis.
During prolonged exercise, BCAA’s are preferentially taken up by the skeletal muscle rather than the liver in order to produce energy. (1)
BCAA supplementation before exercise attenuates the breakdown of muscle proteins during exercise in humans, specifically leucine strongly promotes protein synthesis in skeletal muscle in humans and rats, suggesting that a BCAA supplement may attenuate exercise induced muscle damage and promote recovery. (2)
Sources
1. Armsey, T.D et al. Protein and amino acid supplementation in athletes. Current Sports Medicine Reports. 2003, 4:253-256.
2. Shimomura, Y et al. Nutraceutical Effects of Branched-Chain Amino Acids on Skeletal Muscle. The Journal of Nutrition. 2006, 0022-3166/06