Abstract:
Objective:The effect of proteinsupplementation on athletic performance
and hormonal changes was examined in 32experienced collegiate strength/power
athletes participating in a 12-weekresistance training program. Method:
Subjects were randomly assigned to eithera protein supplement (PR; n = 22) or a
placebo (PL; n = 10) group. During eachtesting session subjects were assessed for
strength (one repetition maximum [1-RM]bench press and squat), power (Wingate
anaerobic power test) and bodycomposition. Resting blood samples were
analyzed at weeks 0 (PRE), 6 (MID) and12 (POST) for total testosterone, cortisol,
growth hormone, and IGF-1. Result:There was seen no difference in energy
intake between PR and PL (3034 ± 209kcal and 3130 ± 266 kcal, respectively),
but a significant difference in daily proteinintake was seen between PR (2.00 g·kg
body mass[BM]-1·d-1) and PL (1.24g·kgBM-1·d-1). A greater change (p <
0.05) in the 1-RM squat was seen in PR(23.5 ± 13.6 kg) compared to PL (9.1 ±
11.9 kg). No other significant strength orpower differences were seen between the
groups. Cortisol concentrations weresignificantly lower at MID for PL and this
difference was significantly different thanPR. No significant changes were noted in
resting growth hormone or IGF-1concentrations in either group.
Conclusion: Although proteinsupplementation appeared to augment
lower body strength development, similarupper body strength, anaerobic power and
lean tissue changes do not provide clearevidence supporting the efficacy of a 12-
week protein supplementation period inexperienced resistance trained athletes.
Machine summary:
"A; Noura M Department of Physical Education, Fars science and Research Branch, Islamic Azad University, Fars, Iran Abstract Objective: 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.
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.
However, there have only been a few studies that have examined the effect of prolonged protein supplementation on changes in resting hormonal concentrations in experienced resistance trained competitive strength/power athletes.
Thus, the purpose of this study was to examine the effect of protein supplementation on strength, power, body composition and resting endocrine concentrations during a 12-week resistance training program in competitive strength/power athletes.
This present study appears to be the first to examine the effects of protein supplementation on performance gains in experienced resistance-trained college strength/power athletes.
This is supported by previous studies demonstrating elevations in training volume, despite higher daily protein intake, can result in significant elevations in resting cortisol concentrations (Volek et al.
However, results of 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."