Int J Sports Med 1991; 12(2): 228-235
DOI: 10.1055/s-2007-1024673
© Georg Thieme Verlag Stuttgart · New York

Endogenous Anabolic Hormonal and Growth Factor Responses to Heavy Resistance Exercise in Males and Females

W. J. Kraemer2 , S. E. Gordon2 , S. J. Fleck4 , L. J. Marchitelli1 , R. Mello1 , J. E. Dziados1 , K. Friedl1 , E. Harman1 , C. Maresh3 , A. C. Fry2
  • 1Exercise Physiology Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007
  • 2Center for Sports Medicine, The Pennsylvania State University, University Park, PA 16802
  • 3Exercise Science Program and the Department of Physiology and Neurobiology, The University of Connecticut, Storrs, CT 06259
  • 4Sport Science Program, U.S. Olympic Committee, Colorado Springs, CO 80909 USA
Further Information

Publication History

Publication Date:
14 March 2008 (online)


To examine endogenous anabolic hormonal responses to two different types of heavy resistance exercise protocols (HREPs), eight male and eight female subjects performed two randomly assigned protocols (i. e. P-1 and P-2) on separate days. Each protocol consisted of eight identically ordered exercises carefully designed to control for load, rest period length, and total work (J) effects. P-1 utilized a 5 RM load, 3-min rest periods and had lower total work than P-2. P-2 utilized a 10 RM load, 1-min rest periods and had a higher total work than P-1. Whole blood lactate and serum glucose, human growth hormone (hGH), testosterone (T), and somatomedin-C [SM-C] (i. e. insulin-like growth factor 1, IGF-1) were determined pre-exercise, mid-exercise (i. e. after 4 of the 8 exercises), and at 0, 5, 15, 30, and 60 mm post-exercise. Males demonstrated significant (p < 0.05) increases above rest in serum T values, and all serum concentrations were greater than corresponding female values. Growth hormone increases in both males and females following the P-2 HREP were significantly greater at all timepoints than corresponding P-1 values. Females exhibited significantly higher pre-exercise hGH levels compared to males. The P-1 exercise protocol did not result in any hGH increases in females. SM-C demonstrated random significant increases above rest in both males and females in response to both HREPs. These data suggest that the hormonal response patterns to HREPs are variable and in females differ from those in males due to significantly higher pre-exercise and exercise-induced serum T levels in males and higher pre-exercise serum hGH concentrations in females.