فصلنامه علوم زیستی ورزشی
پیاپی 1 (تابستان 1388)

The purpose of this research was to study the effect of one session of a progressive endurance running in two environments (natural temperature and moderate temperature) on some markers of the clotting system (fibrinogen, activated thromboplastin time or APTT, prothrombin time or PT) in active girls. 27 physical education female students from Mazandaran University were selected and divided randomly into three groups: exercise in an environment with natural temperature or NTG group (23+2c), exercise in an environment with moderate temperature or HTG group (33+2c) and a group without exercises called HG which was only exposed to an environment with moderate temperature. Laboratory environment humidity was maintained in the range of 55+5% for all groups. The protocol was performed based on Karvonen formula with intensity 65%-75% VO2max for each subject on a non-gradient treadmill. The blood samples following 12 to 14 hours of a nightly fasting were gathered in a similar condition in three phases: the baseline level, mid-test and 30 minutes after the exercise. Coagulant manner was used to determine the levels of fibrinogen, APTT, and PT. The data were analyzed by repeated measures, ANOVA and t – student at P?0.05. The results showed that fibrinogen levels in three groups increased insignificantly in all phases. On the other hand, the increase of PT in NTG group in the mid-test and posttest and in NTG and HTG groups in posttest was significant when compared with the baseline level. Inter-group changes showed a significant difference in PT level between HG and HTG groups in the posttest phase. Based on these findings, it can be said that physical activity with moderate intensity induced the changes in clotting system, but mild heat stress did not affect the blood clotting system.

The purpose of this study was to determine the effect of interval sprint exercise and a detraining period on lipid peroxidation (MDA) and the response of antioxidant system (FRAP, uric acid, bilirubin and total protein). For this purpose, 35 male rats were divided randomly into two groups: sprint group (experimental) (n=20) and control group (n=15, without any training). Experimental group trained for 12 weeks, 3 sessions per week with given intensities (five trained rats experienced the detraining so that the effects of detraining could be studied from 8th to 12th week). During our experiments, animals were individually housed in a climate-controlled (temperature and humidity) animal laboratory. They had 12:12 hours of light-dark cycle as well as standard rat chow. MDA and FRAP were measured manually while other measurements were performed by a kit. Data were analyzed by two-way repeated ANOVA. The results showed a significant difference between two groups in MDA (P=0.022), FRAP (P=0.005) and bilirubin (P=0.002), durig at least one of the evaluation periods while total protein and uric acid remained unchanged. In the experimental group, indeed, there was a significant difference among various assessments in MDA (P=0.001), FRAP (P=0.001), bilirubin (P=0.008) and uric acid (P=0.012). Generally, this protocol of sprint exercise causes an adaptation of antioxidant system and lipid peroxidation, but detraining reverses these results.

The purpose of this study was to examine the longitudinal responses of pulmonary volumes and capacities to serum cortisol in young wrestlers. For this purpose, 24 healthy young wrestlers (age 23.9±0.8 years, height 180.64±0.7 cm, weight 76.3±7.3 kg, BMI 23.4±8.5) volunteered to participate in this study. The subjects performed an incremental wrestling training up to 85% of MHR of the training, three times a week for 12 weeks. The pulmonary tests were performed at rest, first six weeks of training (intensity of 75%), second six weeks of training (intensity of 85%), and at the end of a one–week recovery period. Blood samples were collected to measure serum cotrisol by ELISA. The serum cortisol changes during 12 weeks of the high intensity wrestling training significantly affected FIV1 (P=0.001, stage 2), VC (P=0.037, stages 1,2), Tv/Ti (P=0.001, stage 2) so that a change in every unit of cotrisol were accompanied by a significant change in these pulmonary variables. The results of this study suggested that following 12 weeks of high intensity wrestling training, some pulmonary volumes and capacities of wrestlers changed due to the effect of serum cortisol. No such results have been reported so far.

To investigate the effect of exercise on cortisol responses and energy expenditure in obese and lean men, we measured the energy expenditure (EE) and salivary cortisol responses of six obese (age 22.83± 1.9 yr; Vo2max,35.45±3.9 ml/min/kg; BMI 18.2±1.3 kg/m2) sedentary men. The protocol was running on a treadmill for 30 minutes with 65% maximal oxygen consumption. Student t-test and one-way ANOVA with repeated measures were used to evaluate cortisol, EE, Vo2 and RER between groups during the baseline and exercise periods (P<0.05). Our results showed that during the baseline period, there were no differences between lean and obese groups in salivary cortisol. In contrast, immediately, 15 minutes and 30 minutes after the exercise, obese group had significantly higher cortisol concentration than lean group (P<0.05). In obese group, mean EE (Kcal/min or kcal/min/FFM) was significantly higher than lean group, but there were no differences in RER and VO2 between lean and obese groups (P<0.05). It can be concluded that body fat percent affects cortisol response and energy expenditure, and obese men had higher EE and cortisol levels after 30 minutes of exercise than lean men.

It has been suggested that ghrelin may play a role in the response of growing hormone (GH) to exercises. The present study was designed to examine the effects of 6 weeks of wrestling and a wrestling–based circuit exercise (WBCE) on plasma ghrelin and some glucoregulatory hormones in well-trained wrestlers. 30 well-trained male wrestlers (age 18.5±1.5 and BMI 24.8±6.81) voluntarily participated in 6 weeks of wrestling and WBCE exercise. Measured variables were plasma ghrelin and glucose, serum GH, cortisol and insulin. Results showed that 6 weeks of training resulted in a significant decrease in GH, cortisol and serum insulin and a significant increase in plasma ghrelin. We concluded that an increase in ghrelin in response to a negative energy balance could not increase GH secretion and other possible mechanisms are involved in this process.

It is well established that the active continuous recovery is preferred to passive recovery. But the active period of this recovery is long (20-60 minutes) and the intensity is not controlled. Furthermore, most severe trial exercises need short-term active recovery for better performance so that the athletes can return more rapidly to their normal state and more desirable performance. However, this type of recovery is not thoroughly known concerning time, intensity and type of activity. The purpose of this study was to examine the effect of short duration (3 minutes) active recovery for repeated climbing trial on blood lactate, LDH and CPK concentration in young male elite climbers. For this purpose, 10 elite male rock climbers (age=24±2.92 years), (weight=60±6.19 kg), (height=173±5.73 cm) and (BMI=19±2.98) volunteered to participate in this study. The subjects participated in two tests with a 5-day interval; in the first test, each climber completed four 2-minute climbing trials and 3 minutes of passive recovery; in the second test, each climber completed the same trials but 3 minutes of active recovery. During each 3 minutes of active recovery, every subject ran on a treadmill with 45% VO2max. 2 minutes were considered for blood sampling before each climbing trial. To measure blood lactate, blood samples were collected from earlobe capillaries and for LDH and CPK enzymes, blood samples were gathered from antecubital vein collected during each refocusing phase. Blood samples were taken following the warm-up before the first climbing and after each recovery. The results showed a significant difference between active and passive recovery conditions in lactate concentration, LDH (P<0.005) and CPK (P<0.039) blood enzymes. These factors were lower across all four climbing trials in active recovery. After each active recovery, climbers started the next trial with a lower arterial lactate concentration, LDH and CPK than passive recovery.

Nowadays, doping is an intricate dilemma for athletes. Wrestling is the domestic, national and popular sport in Iran. Meanwhile, the prevalence of drug abuse in wrestling is high due to its power-demanding nature. So, we decided to evaluate the knowledge of club wrestlers of Tehran about doping and their estimates of current prevalence in the country. In a cross sectional study, 426 wrestlers were studied during 1385-1386. For this purpose, a questionnaire was used and its validity and reliability were approved in a pilot study of 30 athletes. In this study, researchers selected the clubs by randomized clustered sampling, distributed the questionnaires among wrestlers and collected the completed forms. Data were analyzed with SPSS software. The knowledge of wrestlers in three categories of doping definition, recognition of prohibited drugs and side effects was poor or moderate (70.8%, 95.8% and 99.5% respectively). 4/8%, 13% and 5.2% of participants regarded their friends, coaches and physicians as their main consultants. 35.4% and 12.5% of wrestlers estimated over 50% prevalence of drug abuse in professional leagues and their own clubs respectively. It seems that wrestlers of Tehran do not have good knowledge about doping materials. It seems necessary to design a comprehensive educational program for all audiences aimed to eliminate the ignorance, to correct the inappropriate attitudes, to warn about the adverse consequences and to pay attention to values of fighting against doping.

The purpose of this study was to investigate the effect of caffeine ingestion on anaerobic power; fatigue index and blood lactate levels in boys athlete students. Among voluntarers 16 subjects were selected and devided into two caffeine and placebo groups in a simple – randomized manner base on fatigue index in the pretest. They were asked to prevent from doing intensified activities 24 hours prior to test start and eating or drinking which included any caffeine – related materials. The primary RAST test, as a pretest, was performed following 4 hours of lunch meal and after 6 minutes their blood lactate was measured. The secondary rast test was done after a week exactly like the first session: the subjects go on ingestion caffeine casually and interrupt it 48 hours prior to test in post test; the subjects took 6mg/kg caffeine or placebo one hour prior to test start. Dpendent and independent t –test were used as statistical method (P= 0.05) and finding suggest that caffeine ingestion has a significant positive effect on mean power, low power and fatigue index. Totally, it can be noted that caffeine ingestion is effective in shuttle – run performance.