The Combined Effects of Protein Intake and Resistance Training on Serum Osteocalcin Concentrations in Strength and Power Athletes

Abstract

The purpose of the present investigation was to examine the combined effects of protein intake and resistance training on a blood marker of bone osteogenesis, serum osteocalcin, in Division III football players. Thirty-three resistance-trained football players (age = 20.4 +/- 1.8 years; height = 180.9 +/- 7.0 cm; body mass = 97.2 +/- 12.6 kg) were evaluated on their protein intake and subsequently underwent 10 weeks of periodized heavy resistance training during the off season. Subjects were then placed into 1 of the following 3 groups based on relative protein intake and were instructed to maintain their diets throughout the experimental period: (a) low protein intake (<1.2 g per kilogram of body mass), (b) moderate protein intake (1.21 to 1.90 g per kilogram of body mass), or (c) high protein intake (>1.91 g per kilogram of body mass). Blood sampling occurred prior to and following the 10-week resistance training period to determine resting serum osteocalcin concentrations. A significant main effect was observed following training such that only the group who consumed <1.2 g per kilogram of body mass of protein shown significant elevations in serum osteocalcin in response to resistance training (26.8 +/- 6.4 to 33.4 +/- 6.6 ng.ml(-1)). In addition, absolute protein intake was significantly correlated to serum osteocalcin concentrations (r = 0.39). The results of the present investigation demonstrated relationships between protein intake and serum osteocalcin concentrations. In addition, the osteocalcin response to short-term resistance training appeared to be affected by protein intake.