Muscle-mass Gain After Resistance Training Is Directly Related To Plasma IGF-1 And Inversely Correlated With Trunkal Fat In Post-menopausal Women

Abstract

There is growing evidence indicating the role of decreased of estrogen production (menopause), lower insulin-like growth factor (IGF-1) and fat gain in the pathogenesis of sarcopenia. PURPOSE: The effects of long term resistance training on muscle mass gain and fatness changes in association of plasma chemical mediators (FSH, E2, IGF-1 and IL-6) were investigated in post menopausal women. METHODS: In clinical study of convenience sample 22 women aged 40-70 years, >12 months amenorrhea concluded, a supervised strength protocol of progressive exercises (60-80% 1-RM) for lower and upper limbs, 3 day/week, 9 months long. At baseline (M0) and end (M1) of experiment, body composition (DXA) and plasma levels of IGF-1, FSH and E2 (immulite system) and IL-6 (ELISA, R&D systems) were assessed. Statistical analyses using STATISTICA 6.0 were used for estimating single correlation coefficient (Pearson), partial correlations and multiple regression (forward stepwise) for p<0,05. RESULTS: At baseline (M0) MM correlated positively with E2 (r=0.45). The delta trunk fat (kg) correlated positively with the IL-6 changes (r=0.68). The gained MM correlated positively with plasma IGF-1 at M0 (r=0.47) and negatively with timing of amenorrhea (r=-0.44) and variation of plasma IL-6 (r=-0.73). When adjusted for all confounding variables only basal IGF-1 (positively) and variation of IL-6 (negatively) influenced muscle mass and only trunkal fat accretion influenced IL-6. CONCLUSION: Thus muscle gain in post menopausal women after strength training was related to their IGF-1 basal status and inversely to the trunkal fat (and IL-6) with the later being probably related to the former. Support by CNPq, CAPES.