Effect of amino acids on IGF1 gene expression in human myotubes and skeletal muscle.

Objective: Insulin-like growth factor I (IGF1) is an important regulator of collagen and extracellular matrix protein expression. We aimed to evaluate the effect of amino acids (AAs) on expression of IGF1 and IGF1-dependent genes in human myotubes and skeletal muscle and supposed that AAs administration increases IGF1 levels in blood and expression of IGF1 and IGF1-dependent genes in trained skeletal muscle, thereby reducing training-induced muscle damage.

Design: Human myotubes were incubated with Arg and Leu for 24 h.

Comprehensive overview of hemoglobin mass and blood volume in elite athletes across a wide range of different sporting disciplines.

Background: The aim of the study was to compare total hemoglobin mass (tHb-mass) and blood volume (BV) across elite athletes with different sporting specializations.

Methods: The study enrolled 222 members of Russian national teams from 12 different sporting disciplines and non-Olympic sports. The athletes were tested in the middle of a competitive season for tHb-mass, BV, plasma volume (PV), hemoglobin concentration (Hb), and hematocrit level (Hct) determination.