The aim of this study is to determine the impact of resistance training on growth hormone (GH) concentrations, pulse characteristics of GH secretion and GH actions on target tissue. Serial blood sampling over 16 hours will be performed to measure GH concentrations under normal conditions and high volume heavy resistance exercise. It is hypothesized that GH will increase in response to the exercise dose, due to an increase in width and amplitude of Gh pulses. Gh immunoreactivity is expected to show an exercise -dose relationship where the greatest response is expected in the lower molecular weight range. It is also expected that there is an erercise-dose relationship on the proliferation of myotubes.