Document Type : Original Article(s)
Authors
1
Associate Professor of Exercise Physiology, School of Physical Education and Sport Sciences, The University of Isfahan, Iran.
2
School of Physical Education and Sport Sciences, The University of Isfahan, Iran.
3
PhD Student, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Abstract
Background: The purpose of this study was to compare four resistant training protocols on level of human growth hormone secretion in beginner male athletes. Methods: In a semi-excremental study, 12 healthy male subjects were chosen randomly among beginner athletes with mean age: 22.3 ± 2.2 years, height: 178.5 ± 4.03 cm, weight: 73.9 ± 3.02 kg and body mass index: 23.26 ± 1.1 kg/m2. Bilateral knee extension exercise used as the exercise movement. Each of athletes was participated in four training protocols and concentration of human growth hormone was measured before and immediately after each exercise. Interval between executing each of exercise protocols was one week. Before implementing the exercise protocol, 1RM of bilateral knee extension was measured. Protocol 1 included 5 set at 90% of 1RM, with 3-min rests until tired. In second, third and fourth protocols, after doing last set (fifth set) and 30-seconds of rest, an additional set with 50%, 30% and 20% of 1RM until tired was performed. The obtained data were analyzed using analysis of variance (ANOVA) with repeated measures for differences among training protocols, Scheffe post hoc comparison and students paired t-test for differences between correlated means. Findings: The executing second protocol (T50) and third protocol (T30), increased human growth hormone concentrations after exercise significantly (P < 0.001); whereas firs protocol (T1) and fourth protocol (T20) caused no significantly change in human growth hormone concentrations after exercise (P > 0.05). Conclusion: The results of present research showed that adding a set of 50% or 30% of 1RM until tired to a training program done by high intensity and low repetition will increase amount of hormone secretion significantly after exercise. Keywords: Resistant training, Muscular strength, Human growth hormone.
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