This Article Full Text Full Text (PDF) Services Download to citation manager PubMed PubMed Citation

Adrenergic Receptor Genotype Influence on Midthigh Intermuscular Fat Response to Strength Training in Middle-Aged and Older Adults

Departments of ¹ Nutrition and Food Science and ⁴ Animal and Avian Sciences, College of Agriculture and Natural Resources, and ² Department of Kinesiology, College of Health and Human Performance, University of Maryland, College Park.
³ United States Department of Agriculture, Diet and Human Performance Laboratory, Agriculture Research Service, Beltsville Human Nutrition Research Center, Beltsville, Maryland.

Address correspondence to Ben Hurley, PhD, Department of Kinesiology, University of Maryland, College Park, MD 20740. E-mail: benhur{at}umd.edu

Background. There is little information regarding the effects of strength training on intermuscular fat (IMF). This study examines changes in IMF in response to strength training in carriers of the adrenergic receptor (ADR) ß2Glu27 polymorphism versus noncarriers and between carriers of ADR2b Glu⁹ polymorphism versus noncarriers.

Methods. Midthigh IMF and muscle area were measured by computed tomography (CT) before and after 10 weeks of single-leg strength training in healthy, sedentary middle-aged and older (50–83 years) men (n = 46) and women (n = 52) in both their trained and untrained (control) legs.

Results. The strength training program resulted in a substantial increase in one-repetition maximum strength (p <.001) and muscle area (p <.001), but no significant changes in IMF in the whole group. However, IMF was significantly reduced with strength training in participants carrying ADRß2 Glu27 (–2. 3 ± 1.0 cm², p =.028), but no significant change was observed with ADRß2 Glu27 noncarriers. The decrease in IMF in ADR2b Glu⁹ carriers (–1.9 ± 1.0 cm², p =.066) was significantly different (–2.9 ± 1.5 cm², p =.043) from a nonsignificant increase in ADR2b Glu⁹ noncarriers. ADRß2 Glu27 carriers who also carried ADR2b Glu⁹ significantly lost IMF with strength training (–3.8 ± 1.5 cm², p =.018).

Conclusion. ADR genotype influences IMF response to strength training.