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OBJECTIVES: To examine the possible influences of age and gender on muscle volume responses to strength training (ST). DESIGN: Prospective intervention study. SETTING: University of Maryland Exercise Science and Wellness Research Laboratories. PARTICIPANTS: Eight young men (age 20–30 years), six young women (age 20–30 years), nine older men (age 65–75 years), and ten older women (age 65–75 years). INTERVENTION: A 6-month whole-body ST program that exercised all major muscle groups of the upper and lower body 3 days/week. MEASUREMENTS: Thigh and quadriceps muscle volumes and mid-thigh muscle cross-sectional area (CSA) were assessed by magnetic resonance imaging before and after the ST program. RESULTS: Thigh and quadriceps muscle volume increased significantly in all age and gender groups as a result of ST (P < .001), with no significant differences between the groups. Modest correlations were observed between both the change in quadriceps versus the change in total thigh muscle volume (r = 0.65; P < .001) and the change in thigh muscle volume versus the change in mid-thigh CSA (r = 0.76, P < .001). CONCLUSIONS: The results indicate that neither age nor gender affects muscle volume response to whole-body ST. Muscle volume, rather than muscle CSA, is recommended for studying muscle mass responses to ST. [ABSTRACT FROM AUTHOR]

To determine the influence of angiotensinogen (AGT) A–20C, M235 T, and angiotensin II type 1 receptor (AGTR1) A1166C genotypes on resting blood pressure (BP) response to strength training (ST) in older men and women.Prospective intervention study with retrospective genotyping.University of Maryland Exercise Physiology Laboratory.Seventy sedentary, healthy older men (n=34) and women (n=36).Approximately 23 weeks of ST performed 3 days per week.Resting BP was measured on six separate occasions before and after ST for each subject. AGT and AGTR1 genotyping was performed retrospectively from each subject's genomic deoxyribonucleic acid.Systolic BP decreased in C-allele carriers at the AGT A–20C locus with ST (122±1 to 116±2 mmHg,P<.05), which was significantly greater than the decrease in the A homozygotes (126±1 to 123±1 mmHg,P<.05). At the AGTR1 A1166C locus, diastolic BP decreased to a greater extent in the C-allele carriers (76±1 to 70±2 mmHg,P<.05) than in the A homozygotes (75±1 to 72±1 mmHg,P<.05).The AGT A–20C and AGTR1 A1166C genotypes may influence resting BP response to ST, such that C-allele carriers at each of these loci reduce their resting BP in response to ST to a greater extent than A homozygotes. [ABSTRACT FROM AUTHOR]