Effects of Protein Supplementation on Muscular Performance and Resting Hormonal Changes in Collegiate Athletic

Researchers in Sport Science Quarterly

مقاله 2، دوره 1، شماره 1، اردیبهشت 2010، صفحه 8-18   

نویسندگان

SH Sheibani؛ M.A Refahiat؛ M Noura

Department of Physical Education, Fars science and Research Branch, Islamic Azad University, Fars, Iran

چکیده

The effect of protein supplementation on athletic performance and hormonal changes was examined in 32 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Method: Subjects were randomly assigned to either a protein supplement (PR; n = 22) or a placebo (PL; n = 10) group. During each
testing session subjects were assessed for strength (one repetition maximum [1-RM] bench press and squat), power (Wingat anaerobic power test) and body composition. Resting blood samples were analyzed at weeks 0 (PRE), 6 (MID) and 12 (POST) for total testosterone, cortisol, growth hormone, and IGF-1. Result: There was seen no difference in energyintake between PR and PL (3034 ± 209 kcal and 3130 ± 266 kcal, respectively), but a significant difference in daily protein intake was seen between PR (2.00 g·kg body mass[BM]-1·d-1) and PL (1.24 g·kgBM-1·d-1). A greater change (p < 0.05) in the ǻ 1-RM squat was seen in PR (23.5 ± 13.6 kg) compared to PL (9.1 ± 11.9 kg). No other significant strength or power differences were seen between the groups. Cortisol concentrations were Sheibani, SH ( )
sh. significantly lower at MID for PL and this difference was significantly different than PR. No significant changes were noted in resting growth hormone or IGF-1 concentrations in either group. Conclusion: Although protein supplementation appeared to augment lower body strength development, similar upper body strength, anaerobic power and lean tissue changes do not provide clear evidence supporting the efficacy of a 12- week protein supplementation period in experienced resistance trained athletes.

کلیدواژه‌ها

Sport nutrition؛ Resistance training