Growth Hormone Response to an Acute Bout of Resistance Exercise in Weight-Trained and Non-Weight-Trained Women

The serum growth hormone (GH) response of 6 non-weight-trained (NWT) and 6 weight-trained (WT) eumenorrehic, ovulatory women performing a heavy resistance exercise protocol (HREP) in the early follicular phase was examined. The HREP consisted of 7 different exercises and utilized a moderate resistance (10 repetition maximum) with short rest periods (1 minute). GH was evaluated preexercise, immediately postexercise, and 5, 15, 30, and 60 minutes postexercise. A significant difference was observed between groups (n = 6) for GH at preexercise, immediately, and 5 minutes postexercise (p < 0.05). The integrated area under the curve (AUC) for GH revealed no significant difference between groups (n = 6). However, after removing 2 subjects who were outliers (n = 5), significant differences in both the GH response over time (p < 0.01) and AUC GH (p < 0.01) were observed between groups. The most notable findings were that WT women demonstrated lower preexercise GH concentrations than their NWT counterparts with all subjects (n = 6; WT 2.47 ± 1.27 μg · L^-1; NWT 4.99 ± 1.23 μg · L^-1, p < 0.01) and with the removal of outliers (n = 5; WT 1.21 ± 0.21 μg · L^-1; NWT 4.08 ± 1.0 μg · L^-1, p < 0.01). Additionally, the HREP elicited a greater overall GH response in the WT group (n = 5; WT 179.6 ± 59.5 μg · L^-1; NWT -15.1 ± 16.7 μg · L^-1) as reflected by the integrated AUC (p < 0.01). The lower preexercise GH concentrations and greater overall GH response of the WT group suggest that, in women, GH response to resistance exercise varies with training status.