Title

Effects of heavy resistance exercise volume on post-exercise androgen receptor content in resistance-trained men

Date of Completion

January 2003

Keywords

Biology, Animal Physiology|Health Sciences, Recreation

Degree

Ph.D.

Abstract

The purpose of the present investigation was to examine the acute hormonal response in the blood and androgen receptor content in the vastus lateralis muscle following two resistance exercise protocols consisting of different volume. Nine men with resistance training experience [7.9 ± 3.9 years; one-repetition maximum (1 RM) squat = 152.2 ± 32.3 kg] performed the squat exercise for 1 (SS) and 6 sets (MS) of 10 repetitions with 80–85% of 1 RM in a random, counter-balanced order separated by one week. Muscle biopsies were performed at baseline (10 days prior to the first protocol), and 1 hour following each protocol. Blood was collected prior to, immediately following (IP), and every 15 minutes after each protocol for 1 hour. Both protocols resulted in significant reductions in plasma volume (SS = −15.6 ± 3.3%, MS = −21.6 ± 3.1%) and elevations in lactate (SS = 6.3 ± 2.9 mmol · L−1; MS = 15.7 ± 3.6 mmol · L−1) at IP with the magnitude of increase significantly greater following MS. For serum total testosterone, no acute elevations were observed following SS whereas significant elevations were observed at IP (16%), 15 (23%), and 30 (18%) min post exercise following MS. For plasma cortisol, no differences were observed for SS over time except for a reduction at 60 min post exercise whereas significant elevations were observed for MS at IP (31%), 15 (48%), and 30 (49%) min post exercise. For the free androgen index (ratio of total testosterone to sex hormone-binding globulin), significant reductions were observed at IP and 45 min post exercise following SS whereas only trends for elevations were observed at 15 and 30 min post exercise following MS. Androgen receptor content did not change 1 hour following SS but significantly decreased by 46% following MS. These results demonstrated that the volume of resistance exercise significantly affected the acute metabolic and hormonal responses. In addition, the higher volume of resistance exercise resulted in a reduction in androgen receptor content in skeletal muscle 1 hour post exercise possibly due to greater protein catabolism associated with the higher level of stress. ^