Research in Sport Medicine and Technology

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Introduction and aim: The aim of present study was to assess the effect of six weeks Badminton training
on changes of stress and cortisol levels in non-athletic female students. Materials and Methods: In this
study estimated stress of 120 non-athlete students by stress questionnaire (HAD scale). Were measured
Among subjects who had suffered highest stress, 30 subjects with a mean age of 86/2 ± 22 years, height
56/5 ± 163 cm and weight 95/4 ± 57 kg were selected. Cortisol were measured by the bloodletting. The
subjects were divided into two experimental and control groups as homogeneous. But the control group did
not perform any activity. After training protocol variables were measured again in the same conditions. To
estimate the effect of independent variables on the dependent variable of the t-test and the independent ttest
to compare groups with a significance level (p <0/05) was used. Data were analyzed using spss and
Excel software.
Results: The results of this study showed that doing a six-week badminton practice reduces cortisol levels
(p =0.005), and decreasing stress (p =0.03) in the experimental group.
Conclusion: There was significant change in levels of cortisol and stress in experimental group.

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Determining the intensity of exercise in children's sports programs has always been very important. The aim of this study was to investigate the rope skipping exercise with three different intensities on the acute response of salivary chromogranin A and alpha-amylase in girl students. 45 fourth grade students were divided into three groups (low, moderate and high intensity). They performed one session of rope skipping with three intensities of 50, 65, and 75% reserve heart rate, according to the metronome rhythm. The reserve heart rate was calculated by the Karvonen method. Samples of salivary immunoglobulin A and cortisol were collected before and immediately after the exercise and measured by the ELISA method. T-test and analysis of variance were used to evaluate the data. Alpha-amylase and chromogranin A increased significantly after all three intensities. It was Also shown that there is no significant difference between intensities in the amount of chromogranin A, While the amount of alpha-amylase in the group with an intensity of 75% of the reserve heart rate was more than 50%. Although more research is needed in this area, according to the present results, it can be said that probably a session of rope skipping with 50% of reserve heart rate has a less increasing effect on salivary alpha-amylase of girl students.

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The purpose of this research was to determine the effect of different doses of caffeine chewing gum on stress hormones and shooting performance of military men. The subjects of the present research were 10 commanders of Valiasr Police Training Center in Tabriz with a mean and standard deviation of age of 31.52±2.78 years, weight of 75.32±3.91 kilograms, His height was 176.14 ± 4.84 cm. The levels of cortisol, adrenocorticotropic hormone and oxytocin in the blood as well as shooting performance were measured after consuming different doses of caffeine. In the first phase, the placebo was given 15 minutes before the shooting. In the second, third and fourth stages (the time interval between each stage is 5 days), all the subjects were given caffeine gum with doses of 150, 200 and 300 mg 15 minutes before the shooting. Gum and placebo were given to the participants in a double-blind manner. Descriptive statistics, analysis of variance with repeated measures and Tukey's post hoc test were used to analyze the data(P≤0.05). The results of the present study showed that the consumption of caffeine gum in doses of 200 and 300 grams causes a significant decrease in all three stress hormones and also a significant increase in shooting performance, however, the consumption of a dose of 150 mg of caffeine don’t have an effect on the reduction of stress hormones and Shooting performance. According to these results, shooting athletes can be advised to use caffeine gum with doses of 200 and 300 mg before their training and competitions. However, more studies are needed to comment on the use of different doses of caffeine, especially in the form of chewing gum.