Changes in hormonal concentrations after different heavy-resistance exercise protocols in women.

ABSTRACT

Nine eumenorrheic women (age 24.11 +/- 4.28 yr) performed each of six randomly assigned heavy-resistance protocols (HREPs) on separate days during the early follicular phase of the menstrual cycle. The HREPs consisted of two series [series 1 (strength, S) and series 2 (hypertrophy, H)] of three protocols, each using identically ordered exercises controlled for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work (J) within each three-protocol series. Blood measures were determined pre-, mid- (after 4 of 8 exercises), and postexercise (0, 5, 15, 30, 60, 90, 120 min and 24 and 48 h). In series 1, a significant (P < 0.05) reduction in growth hormone (GH) was observed at 90 min postexercise for all three protocols. In series 2, the 10-RM protocol with 1-min rest periods (H10/1) produced significant increases above rest in GH concentrations at 0, 5, and 15 min postexercise, and the H10/1 and H5/1 protocols demonstrated significant reductions at 90 and 120 min postexercise. Cortisol demonstrated significant increases in response to the S10/3 protocol at 0 min, to the H10/1 protocol at midexercise and at 0 and 5 min postexercise, and to the H5/1 protocol at 5 and 15 min postexercise. No significant changes were observed in total insulin-like growth factor I, total testosterone, urea, or creatinine for any of the HREPs. Significant elevations in whole blood lactate and ammonia along with significant reductions in blood glucose were observed. Hormonal and metabolic blood variables measured in the early follicular phase of the menstrual cycle varied in response to different HREPs. The most dramatic increases above resting concentrations were observed with the H10/1 protocol, indicating that the more glycolytic HREPs may stimulate greater GH and cortisol increases.