Branched-chain amino acids (BCAA) are a common supplement in sports and resistance training. Their theorized benefit is increasing lean body mass and maximizing strength gains.
BCAA and leucine particularly utilize a signaling route which overlaps with the distal part of the insulin-like growth factor I (IGF-I) signaling pathway, namely the mammalian target of rapamycin (mTOR) cascade (mTORC1).
Haegens et al looked to see if BCAA and leucine increase mTOR signaling, muscle mass, and muscle fibers (myofibrillar) protein content.
What was done
The researchers measured C2C12 skeletal muscle cells using cultures.
Leucine directly induces myofibrillar protein accretion in skeletal muscles. Leucine involved a process leading to mTOR activity.
Leucine appears to be beneficial for stimulating myofibrillar protein rather than generic protein accretion in skeletal muscle. This implies a mTOR dependent and independent regulation.
Improving in-water strength is essential in swimming. However, many of these gains are with biomechanics and/or neural improvements. Therefore, increasing muscle mass for improving strength in swimming is uncertain, but potentially beneficial.
- Haegens A, Schols AM, van Essen AL, van Loon LJ, Langen RC. Leucine induces myofibrillar
protein accretion in cultured skeletal muscle through mTOR
dependent and -independent control of myosin heavy chain mRNA levels. Mol Nutr Food
Res. 2012 May;56(5):741-52.
Originally Posted July 2012