فصلنامه علوم زیستی ورزشی
پیاپی 12 (بهار 1391)

Coronary artery disease (CAD) is a leading cause of morbidity and mortality in most countries. This disease is directly associated with increased low–density lipoprotein cholesterol (LDL-c) and is conversely associated with high–density lipoprotein cholesterol (HDL-c) concentrations. ABCA1 is the main exporter of phospholipid and cholesterol from cells to lipid-free or minimum lipid apolipoprotein. Studies clearly indicated that ABCA1 performance has a key role in the process of reverse cholesterol transport (RCT) and an effective role in preventing cardiovascular disease. The purpose of this study was to investigate the effect of two types of single session exercise (aerobic and resistance) on ABCA1 gene expression in lymphocytes in well – trained girls. 24 female athletes from Khorasan province were randomly selected and assigned to three groups: control (n=8), aerobic (AE) (n=8), and resistance (RE) (n=8). Blood samples of all subjects were collected prior to and after exercise session. Lymphocyte was separated using lymphocyte density gradient centrifugation and ABAC1 m–RNA expression was investigated by semi–quantitative RT-PCR. Data were analyzed by one–way ANOVA test (p≤0.05). Results showed that RE and AE group following one session of exercise significantly increased m-RNA expression of lymphocyte ABCA1 gene (f=8.719 and P≤0.001) while this increase in the RE group was higher than AE (P≤0.005 vs. P≤0.01). This study indicated that one session of aerobic and resistance exercise played an effective role in preventing cardiovascular disease though increased ABCA1 gene expression.

Cardiac function during exercise is assumed to be important in determining exercise tolerance. The aim of this study was to evaluate hemodynamic changes of blood flow at anaerobic threshold and its effect on exercise tolerance. 24 patients with coronary artery disease were voluntarily divided into two groups of experimental (n=12) and control (n=12). The experimental group participated in 8 weeks of exercise-based cardiac rehabilitation program, 3 sessions/week at the intensity of 70%-85% of maximum heart rate (MHR) and 40%-60% of one repetition maximum (1RM). Hemodynamic changes at anaerobic threshold were assessed at baseline and 48 hours after the end of the protocol by the impedance cardiography method. Results demonstrated that training significantly (p<0.05) increased anaerobic threshold (AT), Vo2 peak and some hemodynamic responses at anaerobic threshold. It was observed that exercise-based cardiac rehabilitation program could improve anaerobic threshold via improvement of hemodynamic responses in patients with coronary artery disease.

Cardiac function during exercise is assumed to be important in determining exercise tolerance. The aim of this study was to evaluate hemodynamic changes of blood flow at anaerobic threshold and its effect on exercise tolerance. 24 patients with coronary artery disease were voluntarily divided into two groups of experimental (n=12) and control (n=12). The experimental group participated in 8 weeks of exercise-based cardiac rehabilitation program, 3 sessions/week at the intensity of 70%-85% of maximum heart rate (MHR) and 40%-60% of one repetition maximum (1RM). Hemodynamic changes at anaerobic threshold were assessed at baseline and 48 hours after the end of the protocol by the impedance cardiography method. Results demonstrated that training significantly (p<0.05) increased anaerobic threshold (AT), Vo2 peak and some hemodynamic responses at anaerobic threshold. It was observed that exercise-based cardiac rehabilitation program could improve anaerobic threshold via improvement of hemodynamic responses in patients with coronary artery disease.

This study investigated whether age and gender influenced blood pressure recovery after exhaustive exercise in non-athletic males and females. 60 healthy (blood pressure was especially considered) men and women with no drug and supplement consumption participated in this study and were divided into six groups: 20-30 yr (10 males), 20-30 yr (10 females), 30-40 yr (10 males), 30-40 yr (10 females), 40-50 yr (10 males) and 40-50 yr (10 females). Immediately before the test, subjects’ heart rate and blood pressure was measured twice (after 10 and 15 min. rest) in a sitting position on an ergometer. During the test, heart rate and blood pressure was measured by a blood pressure instrument with a 2-min. interval. The testing protocol started with 3-min. warm-up at a work load of 50 W on the ergometer followed by a step-by-step increase in work load by 20 W each minute until the subjects reached exhaustion. Heart rate (HR) and blood pressure (BP) were measured in the first minute of after the exercise and subsequently each two minutes until these two variables reached their pretest amount. To compare data among the groups, independent sample t test and to determine the effect of gender and age on BP recovery, ANOVA analysis of variance with repeated measures were used. All statistics were analyzed using SPSS (Version 16.0) (P<0.05). Results showed no significant difference in BP recovery among three groups of females (P>0.05) while there was a significant difference in BP recovery among three groups of males (P≤0.05). Also, there was a significant difference in BP recovery between males and females in all three age groups (P≤0.05). It can be concluded that as the effect of gender on BP recovery was observed after a session of exhaustive exercise, coaches and physicians are recommended to consider this finding in non-athletes’ activities and performance.

The purpose of this study was to investigate the prevalence of dietary supplement consumption and other effective factors in athletes in Tabriz. 150 male athletes (23±5 years) from different sport fields volunteered to participate in this study. A 17-item questionnaire was used to investigate subjects’ sport field and sport history, reasons to consume dietary supplements, sources of information on these supplements and the centers in which they can be provided. At the time of study, 45% (N = 68) of participants consumed at least one supplement and 21% (N=31) used dietary supplements in the past. The most popular supplements were creatine (43.3%), whey protein (17%) and multivitamin (13%). The results showed that the main reason for consuming dietary supplements was to meet the dietary needs (35%). Supplement consumption was significantly different in different sport fields. 34% of participants listed coaches as their best source of information on dietary supplements. The majority (44%) of subjects purchased their supplements from pharmacy. The results of this study agreed with previously published data on prevalence of dietary supplement consumption.

Nowadays, research on exercise physiology has developed. Many of studies try to discover body responses or adaptations to exercise training or physical activity. In many cases, human beings are not suitable models to study these mechanisms in vivo due to ethical and legal limitations. Laboratory animals especially mice and rats are appropriate models for these researches. Treadmill is an excellent devise to cover these aims. By a treadmill, intensity, duration and mode of exercise can be easily manipulated. So, the aim of this study was to design and construct a new and updated version of treadmill for laboratory rodents. This treadmill had more advantages than the previous or foreign models including 12 lines, computerized, portable and easy to handle, easy to work with, lighter, positive and negative inclination, range of speed from zero to 100 m/min, manual and automated shocker, cheap, dependent on national technology.

Sphingosine-1-phosphate (S1P) is a bioactive platelet-derived sphingolipid involved in regulation, proliferation, differentiation, hypertrophy and anti-apoptosis of cells and activation of satellite cells. The aim of the present study was to investigate S1P as a growth factor in response to resistance training in male Wistar rats. 24 eight-week-old male Wistar rats (190–250 gr.) were used in this study. After a week of acclimation to the animal facility, the rats were assigned randomly to a control (N=12) or training (N=12) group. Resistance training was performed using a 1-meter ladder with 2 cm distance between the grids with 85° inclination, and weights attached to rats’ tails. The content of sphingosine-1- phosphate (S1P) in the chloroform layer was determined by high performance liquid chromatography (HPLC). To determine mRNA gene expression, Real-time PCR was used. S1P1, S1P2, S1P3, MyoD and Myogenin gene expression was investigated in HFL and SOL. The Results showed that resistance training increased the total content of S1P in plasma (p=0.001) of trained group in comparison with the control group. Furthermore, resistance training increased the gene expression of S1P1 in FHL (p=0.001) and SOL (p=0.000), S1P2 in FHL (p=0.000) and SOL (p=0.603), S1P3 in FHL (p=0.021) and SOL (p=0.009), MyoD in FHL (p=0.000) and SOL (p=0.001) and Myogenin in FHL (p=0.000) and SOL (p=0.000) of experimental group in comparison with control. There was a significant positive correlation between S1P plasma and gene expression of MyoD in the experimental group. There was no significant correlation between gene expression of S1P1 and MyoD gene expression in groups or muscles (p>0.05) while there was a significant positive correlation between gene expression of Myogenin and S1P1. Furthermore, there was a significant positive correlation between S1P2 and MyoD gene expression. There was a significant positive correlation between S1P3 and MyoD gene expression. It can be concluded that resistance training can increase the S1P content in plasma and its receptors. According to structural and functional roles of sphingolipid and its receptors and their increase after resistance training, this factor might be a growth factor and a signaling pathway in skeletal muscle adaptation.

The purpose of this study was to evaluate the effect of short time circuit-resistance exercise with difference intensities on GHI/IGF-I growth axis in healthy male students. For this purpose, 27 male students with mean and standard deviation of age 21.40±1.78 yr, height 172±0.45 cm, weight 68.85±5.39 kg were selected and randomly divided into three resistance exercise groups (each group, 9 subjects) with intensity of 40%,60%, 80%1RM. Resistance circuit exercise program included 10 sessions. One-way ANOVA and paired t test were used to analyze data in SPSS software. Analysis of data showed that circuit resistance exercise with intensity of 40%, 60%, 80% 1RM had a significant effect on GH. Also, circuit resistance exercise with intensity of 40% had a significant effect on IGF-I. It can be concluded that the intensity of one session of circuit resistance exercise can have incremental and different effects on GH and IGF-I.