European Journal of Applied Physiology

, Volume 112, Issue 2, pp 743–753

Does insulin-like growth factor 1 genotype influence muscle power response to strength training in older men and women?

Authors

  • Suchi Sood
    • Department of KinesiologySchool of Public Health, University of Maryland
  • Erik D. Hanson
    • Department of KinesiologySchool of Public Health, University of Maryland
  • Matthew J. Delmonico
    • Department of KinesiologyCollege of Human Science and Services, University of Rhode Island
  • Matthew C. Kostek
    • Department of Exercise ScienceArnold School of Public Health, University of South Carolina
  • Brian D. Hand
    • Department of KinesiologyCollege of Health Professions, Towson University
  • Stephen M. Roth
    • Department of KinesiologySchool of Public Health, University of Maryland
    • Department of KinesiologySchool of Public Health, University of Maryland
Original Article

DOI: 10.1007/s00421-011-2028-7

Cite this article as:
Sood, S., Hanson, E.D., Delmonico, M.J. et al. Eur J Appl Physiol (2012) 112: 743. doi:10.1007/s00421-011-2028-7

Abstract

The CA-repeat polymorphism in the insulin-like growth factor 1 (IGF1) gene promoter region has been associated with strength and circulating IGF-I protein levels. The purpose of the study was to determine if the IGF1 CA-repeat polymorphism influences muscle power at baseline and in response to ST in older adults. Knee extensor peak power (PP) was measured at 50, 60, and 70% of 1-RM strength before and after 10 weeks of unilateral knee extensor ST in older adults, aged 50–85 years, to determine the changes in absolute and relative PP with ST. Subjects (N = 114) were genotyped for the IGF1 CA-repeat polymorphism and grouped as homozygous for the 192 allele, heterozygous, or non-carriers of the 192 allele. The 192 homozygotes had significantly lower baseline PP at 50, 60, and 70% of 1-RM strength than the non-carriers when age, sex, and baseline fat-free mass were covaried (all P < 0.05). This same relationship was observed when the highest PP within these ranges was compared (e.g., 317.6 ± 13.5 for 192 homozygotes and 380.2 ± 16.3 for non-carriers of the 192 allele, P < 0.05). Both absolute and relative PP increased significantly with ST in all genotype groups as expected, but there were no significant relationships among IGF1 genotypes and any of the PP changes. Despite a significant relationship between IGF1 genotype and knee extensor peak power at baseline, IGF1 genotype does not appear to influence changes in knee extensor peak power with ST.

Keywords

GeneticsSkeletal muscleResistance training

Copyright information

© Springer-Verlag 2011