Kinesiology, Vol. 42. No. 1., 2010.
Original scientific paper
Creatine supplementation alters the hormonal response to resistance exercise
Rahman Rahimi
; Department of Physical Education & Sport Science, Islamic Azad University, Branch of Mahabad, Mahabad, Iran
Hassan Faraji
; Department of Physical Education & Sport Science, Azad University, Branch of Marivan, Marivan, Iran
Dariush Sheikholeslami Vatani
; Department of Physical Education & Sport Science, University of Kurdistan, Sanandaj, Iran
Mohammad Qaderi
; Department of Physical Education & Sport Science, Islamic Azad University, Branch of Mahabad, Mahabad, Iran
Abstract
The purpose of this study was to determine the influence of short-term creatine supplementation on hormonal responses to resistance exercise. 27 trained men were randomly divided into a creatine supplementation group [the CR group (n=15), taking 4×5 g creatine monohydrate/day] or a placebo supplementation group [the PL group (n=12), taking 4×7.5 g maltodextrin/day]. A double-blind research design was employed for a 7-day supplementation period. After this period, the participants performed exercise testing. Blood tests occurred on day 1 prior to supplementation loading (1Pre) and after this period [on the exercise testing day: pre-exercise (Pre), immediately post-exercise (IP), and 15 (15P) and 30 (30P) minutes post-exercise] for the measurement of the serum growth hormone and testosterone concentrations. Significant differences in the number of repetitions and volume were seen with CR (7.2±1.3 repetitions, 1560±386 kg) compared to PL (5.6±2 repetitions, 1089±341 kg) at set 5 of the exercise protocol (p=.01). Serum growth hormone and testosterone were significantly higher at 15P in CR (6.1±1.8 ng/ml, 70.1±19 pmol/L) compared to PL (4.1±1.7 ng/ml, 44.8±16 pmol/L) [(p=.02), (p=.01)]. The enhanced exercise performance resulted in a significantly greater increase in both the growth hormone and testosterone concentrations, indicating an augmented anabolic hormone response to creatine supplementation.
Keywords
creatine loading; anabolic hormones; growth hormone; testosterone; exercise performance
Hrčak ID:
54239
URI
Publication date:
21.6.2010.
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