فصلنامه علوم زیستی ورزشی
پیاپی 14 (پاییز 1391)

The aim of this study was to investigate the effect of one session of continuous exercise on a treadmill on HSP72 and TAC levels of the hippocampus of male wistar rats. For this purpose, 20 male wistar rats (weight 165±1 gr. and age 6 to 8 weeks old) were assigned randomly into four groups: one control group and three acute endurance training groups (groups 1,2 and 3 were killed 30 minutes, 4 hours and 24 hours after the exercise respectively). Rats were subjected to treadmill exercise and the speed of the treadmill was 10m./min. and then gradually increased until 18 m./min. (grade 0%). The duration of the treadmill exercise was 60 minutes. The data were analyzed with one-way ANOVA and Tukey post hoc test (P≤0.05). To determine HSP72 and TAC values sandwich Elisa and decolorization were used respectively. Following the acute continuous exercise, no significant change in HSP72 value in group 1(30 min.) and 2(4 hours) was observed compared to control group; but HSP72 value significantly increased in group 3 compared with control group (P=0.019) and group 1 (30 min.) (P=0.015). TAC level of hippocampus significantly increased in all exercise groups compared with control group (p=0.000). In general, acute exercise had a positive effect on HSP72 and TAC levels and increased their protective effect in the hippocampus of wistar rats.

Growth hormone and insulin-like growth factor 1 are anabolic hormones which play a vital role in developing body tracts especially in childhood and adolescence years. Exercise is a motive which influences GH and IGF-1 secretion. Today, water sports are highly recommended due to creating delight in children. Therefore, the purpose of this study was to examine the effect of eight weeks of water training on rest levels of growth hormone (GH) and insulin-like growth factor (IGF-1) in male children. 18 non-athlete boys (mean ± SD age: 10.2±2 yrs, weight: 26.5±3 kg, height: 130.9±6 cm) were randomly assigned to experimental (n=10) or control (n=8) groups. First, fasting blood samples were gathered to measure GH and IGF-1. Experimental group participated in 8 weeks of water training with intensity of 70-80% HRmax for 3 sessions per week and 1 hour per session. Control group did not participate in any exercise. Blood samples were collected again after last session of training to assess serum GH and IGF-1. Dependent and independent t tests were used to analyze data. The results showed no significant effect of 8 weeks of water training on GH and IGF-1 serum concentration (P>0.05) while a significant increase was observed in GH and IGF-1 after 8 weeks in control group. In addition, there was a significant difference in GH and IGF-1 secretion between the two groups after 8 weeks (P<0.05). It was concluded that eight weeks of water training with intensity of 70-80% HRmax did not stimulate GH and IGF-1 secretion in athlete boys agerd between 9 and 11

The aim of this study was to evaluate the effect of maltodextrin supplementation on blood glucose and anaerobic indices of the young male athletes. 30 young male athletes were selected as the sample and assigned to two groups: carbohydrate (CHO: N=15; mean and SD age 16.67±0.8 years, height 171.27±5.22 cm, weight 67.87±4.29 kg) and control (CONT: N=15; mean and SD age 16.73±1.03 years, height 173.34±5.41 cm, weight 69.11±4.25 kg). During the protocol (60 min. running with 70% MHR), subjects consumed 3 ml/kg of body weight of 5% maltodextrin solution or placebo every 15 minutes. Anaerobic capacities such as peak and mean power as well as the fatigue index were measured by Wingate test protocol. Standard glucometer was used to determine blood glucose. ω2 statistical test was used to indicate the effect of maltodextrin supplementation on dependent variables. The results showed that 61.84% decline in blood glucose in control group could be attributed to the effect of independent variable that is assessed as a high effect. The results showed that maltodextrin supplementation during 60 minutes of aerobic activity with 70% MHR had a significant effect and acceptable effect size on the mean changes in blood glucose and anaerobic variables in young males.

Due to an increase in obesity, the aim of the present study was to examine the effect of 12 weeks of endurance training on body weight, food intake, plasma acylated ghrelin and PYY3-36 in obese male rats. 16 male Wistar rats were fed for 9 weeks with a high fat diet (derived from soybean oil) until they reached mean weight of 319±30 g. The rats were randomly divided into control group (n=8) and training group (n=8) (60 minutes of running on a treadmill (grade=0) per session, 15 to 30 m./min., 5 days per week for 12 weeks). The rats were provided with standard food and water ad libitum and every two days, food intake and weight were measured and recorded. Blood samples were collected 24 hours after the last training session and 8 hours of overnight fasting. The ELISA method was used to measure plasma concentration of mentioned hormones. Independent t test showed that the 12 weeks of endurance training significantly decrease in the weight of training group (P=0.001) compared with the control group. During the training period, the mean food intake of training group was significantly lower than control group (p=0.028). There was no significant difference in plasma concentration of acylated ghrelin between the two groups, but plasma levels of PYY 3-36 in the exercise group was significantly higher (p=0.016). It seems that one of the mechanisms of weight loss as a result of endurance training is reduced food intake by increasing plasma levels of PYY3-36.

Attention to the physical and physiological needs of a soccer referee plays an important role in his performance in a match as in order to regulate the rules of the game, the referee should track the event and players by moving inside the pitch continually with no restriction. The aim of this research was to study the variations in workload, heart rate and blood lactate in elite soccer referees of eighth soccer premier league of Iran in first and second halves (first halves of two mid seasons and second halves of first and second mid seasons). 10 elite soccer referees of soccer premier league (international degree, age: 35.5 3.97 yrs, height: 180.1 4.48 cm, weight: 78.18 8.4 kg) in eighth premier league were selected by available non-random sampling method. All subjects were examined in two games (each mid season contained one game). Tests included measuring workload, heart rate and blood lactate in first and second halves (first halves of two mid seasons and second halves of first and second mid seasons). For data analysis, paired t test was used. The results showed no significant difference between workload and blood lactate of first and second halves (P>0.05). Besides, there was no significant difference in heart rate between first and second halves (P>0.05). It seems that workload and competition level, intensity and speed are the most important environmental factors influencing referees’ physiological responses and covered distance. Analysis of eighth premier league results indicated the low workload of current judges and high heart rate on the other hand which showed a lack of proper physical fitness, especially low aerobic fitness, of soccer elite referees of Iran premier league.

The aim of this study was to evaluate the effect of different intensities of short-term exercise on leptin, insulin, cortisol and lipid profiles in overweight and obese children. 24 overweight and obese boys (mean age 15.5±0.65 years old and BMI: 30.09+2.47 kg/m2) participated in this study. All subjects participated in a graded breath to breath gas-analyzer testing by Bruce protocol to measure VO2max. Then, based on the obtained VO2max, they were randomly divided into three groups of 50%, 75% and 85% intensity on a treadmill. Blood samples were collected before, immediately and 30 minutes after the exercise to evaluate plasma glucose, insulin, leptin, lipid profiles and cortisol. Results showed no significant differences among different intensities of short-term exercise in all variables. But intra-group changes showed the significant effect of exercise with 50% intensity on HDL (p=0.006), glucose (p<0.01) and leptin (p=0.004), exercise with 75% on TG (p=0.010), cholesterol (p=0.020) and glucose (p=0.006) and exercise with 85% intensity on HDL (p=0.001), cholesterol (p<0.01), glucose (p=0.038) and leptin (p=0.002). The results suggested that different intensities of a session of exercise had significant effects on leptin, insulin

The aim of this study was to evaluate the health–related physical fitness status of men aged between 50 and 65 in Isfahan. 385 non-athlete men (mean age: 57.73±4.65 years, height: 167.94±6.04 cm, weight: 76.88±9.45 kg) aged between 50 and 65 were randomly selected as the sample. This study used physical fitness standard tests including flexibility test of sit and reach, Rockport walking, curl-up and push-up tests. Independent t test was used to analyze data. The findings revealed that subjects’ status was not optimal in cardiovascular endurance (28.17± 4.05 ml/kg/min), body fat percent (%29.70±6.14), strength and endurance of abdominal muscles (14.77±7.79 curl-ups) and strength and endurance of shoulder girdle (11.54±5.94 push-ups) compared to the available norms and findings of some research. However, subjects’ status was optimal in flexibility (18.82± 9.55 cm). Although the benefits of regular physical activity are obvious to everyone, many reasons such as lack of knowledge about the role of physical activity in promoting life quality, lack of proper facilities and equipment for the elderly, insufficient time, energy, incentive and socio-cultural behavior prohibit the elderly from participating in regular physical activities.

Recently, the role of myostatin (MSTN) in controlling insulin resistance (IR(has been known. The aim of this study was to determine acute and delayed response of MSTN and IR to circuit resistance exercise. For this purpose, 12 healthy men volunteered and participated in 2 sessions of the resistance exercise and control with one-week interval. After a session to instruct how to perform resistance exercise and after measuring one repetition maximum (1-RM), circuit resistance exercise program was performed including 7 movements with 3 sets of 15 repetitions at 55% 1-RM. In each session, blood samples were collected before, immediately after, 1 hour after and 24 hour after the exercise to measure myostatin, glucose and insulin concentration and IR was calculated. Using 2×4 analysis of variance (ANOVA) with repeated measures, exercise time had an insignificant effect on plasma myostatin concentration while plasma myostatin concentration increased immediately after the exercise and 1 and 24 hours after the exercise decreased gradually. Exercise time had a significant effect on plasma glucose and insulin concentration and IR, that is, plasma glucose and insulin concentration and IR increased immediately after the exercise and 1 and 24 hours after the exercise decreased gradually. Interaction of session and time had an insignificant effect on plasma myostatin and glucose concentration, but a significant effect on plasma insulin concentration and IR. In conclusion, circuit resistance exercise cannot have remarkable effects on acute and delayed response of MSTN and IR.