Influence of promoter region variants of insulin-like growth factor pathway genes on the strength-training response of muscle phenotypes in older adults

Abstract

To examine the influence of insulin-like growth factor (IGF) pathway gene polymorphisms on muscle mass and strength responses to strength training (ST), we studied 128 White and Black men and women before and after a 10-wk single-leg knee extension ST program. One-repetition maximum strength, muscle volume (MV) via computed tomography, and muscle quality (MQ) were assessed at baseline and after 10 wk of ST. There was a significant combined IGF1 cytosine adenine (CA) repeat gene effect, which included both the IGF1 CA repeat main effect and IGF1 CA repeat x PPP3R1 insertion-deletion (I/D) gene x gene interaction effect, on the changes in strength (P < 0.01) and MQ (P < 0.05) with ST. There was a trend for a significant gene x gene interaction between IGF1 CA repeat and PPP3R1 I/D for changes in strength (P = 0.07) and MQ (P = 0.06) with ST. The influence of the PPP3R1 A-202C gene polymorphism on change in MV with ST approached significance (P = 0.06). The IGF1 CA repeat polymorphism had a significant influence on the change in strength and MV combined with ST (P < 0.05), whereas the influence of the PPP3R1 I/D polymorphism approached significance (P = 0.08). There were no associations between the IGFBP3 A-202C gene polymorphism and the muscle phenotypic responses to ST. These data suggest that two of the three IGF pathway gene polymorphisms identified in this study influence muscle phenotypic responses to ST in both black and white older men and women.

VCAM‐1 upregulation accompanies muscle remodeling following resistance‐type exercise in Snell dwarf (Pit1dw/dw) mice

“…Such a trade‐off is consistent with reports regarding IGF‐1, a key hormone regulated by growth hormone. Individuals with IGF1 variants associated with high IGF‐1 blood levels gain more strength following resistance training (Hand et al, 2007; Kostek et al, 2005). Yet, genetic polymorphisms in the gene for IGF‐1 receptor, which result in decreased IGF‐1 plasma levels, associate with longevity (Bonafe et al, 2003; Suh et al, 2008).…”

Inter-individual variability in the adaptation of human muscle specific tension to progressive resistance training

“…Numerous resistance training studies in humans have used the 1 RM as a method of determining the effect of resistance training on muscle strength (Charbonneau et al 2008;Hand et al 2007;Hubal et al 2005;Kostek et al 2005;Riechman et al 2004). However, although the 1 RM is a relatively simple task to perform, it involves not just the intrinsic strength of the muscle group but also the actions of synergistic and stabilizing muscles (Rutherford and Jones 1986), thus questioning its suitability for detailed physiological assessment.…”

Are calcineurin genes associated with endurance phenotype traits?

“…Hand et al (2007) recently reported that the insertion/deletion (I/D) polymorphism of PPP3R1 gene, or at least its interaction with IGF1 CA repeat, may inXuence the training responsiveness of muscle strength. The PPP3R1 I/D polymorphism was also associated with left ventricular hypertrophy in hypertensive patients (Tang et al 2005) and athletes (Akhmetov et al 2008).…”