Abstract
The purpose of the present study was to determine the response of glucose (G), insulin (In) and insulin like growth factor (IGF)-I to eccentric (ECC) vs. concentric (CON) resistance exercise in healthy trained and untrained subjects. Venous blood samples were drawn before and immediately after the test, and during 1-hour recovery for the determinations of hormonal and somatomedin concentrations. As compared to resting values, the maximal eccentric (ECC) resistance exercise test caused a significant decrease in G level (p<0.05). Significant differences were observed in post-exercise G level during ECC exercise (p<0.05). Different types of muscle contractions (ECC vs. CON) and resistance training had a significant effect on serum IGF-I concentration at maximal exercise intensity. A significant increase in IGF-I concentration was observed in response to eccentric muscle contraction in trained subjects compared to the control. Conclusions: These results seem to have demonstrated that in healthy subjects increased serum IGF-I concentration might be responsible for better glucose transport during resistance exercise, and this predominantly in eccentric muscle contraction.
