فهرست مطالب ahmad azad

The purpose of this study was to determine the effect of 70percent reduction in training loade during the tapering on serum levels of cortisol, testosterone and performance changes in trained swimmers

In this quasi-experimental study, 20 trained male swimmers were selected by available sampling method and participated voluntarily in the study. Then based on the record of 200m freestyle, the subjects were divided into two groups: Taper(n=10) and control(n=10). Both groups initially Participated in6 weeks in incremental exercises training. Then the taper group spent the 14-day period with a 70% reduction in training load and the control group continued training with the same load as before. In both groups, performance tests (upper and lower body strength) and blood samples (for measurement of serum testosterone, cortisol and testosterone / cortisol ratio) were taken at the beginning of the taper and after the end of this period. For determination of testosterone and cortisol levels, ELISA kits was used. Data were analyzed using, paired t-, and covariance tests.

The results indicated that after the tapering , there was a significant difference between the two groups in swimming performance (200m freestyle), upper and lower strength, serum cortisol levels, and the ratio of testosterone to cortisol(P< 0/05). However, there was no significant difference in testosterone levels between the two groups(P> 0/05).

The findings of this study showed that taper plan with 14-days, improved anabolic conditions and performance in trained swimmers.

Warm and humid conditions are the main limiting factor in long-term activities. Thus, the purpose of this study was to determine the effect of pre-cooling (PC) on exhaustion time, plasma levels of lactate and, electrolytes status of untrained men following an exhaustive exercise in the heat conditions. The participants were 20 untrained male students aged 19 to 21, which were randomly assigned to control and experimental groups (n=10). Core body temperature, skin temperature, heart rate, blood pressure, plasma lactate, and electrolytes were measured in three stages: at baseline, after warm-up and PC, and following the exhaustive test. The PC method consisted of immersion in the cold water (26 °C) for 10 minutes (ambient temperature 32-34 °C). The exhaustive exercise protocol included treadmill running (at 33 °C, 50% humidity) at the speed of 7 km/h, which gradually increased to 10 km/h up to exhaustion. The SPANOVA was used for data analysis; and the criterion of significance was set as p< 0.05. Exercise time to exhaustion was longer (p<0.0001) in the PC than in the control conditions. PC decreased oral (p=0.05) and skin (p<0.0001) temperatures and lactate level (p=0.0001). However, there were no significant differences in plasma K and Na concentration. In conclusion, the PC increases endurance performance in a hot environment through enhances heat storage, decreases lactate level and cardiovascular strain.

This paper aims to study the influence of soil-structure interaction on plastic energy demand spectra directly derived from the energy-balance equations of soil-shallow-foundation structure with respect to an ensemble of far-field strong ground motions obtained from Pacific Earthquake Engineering Research (PEER) database and recorded on alluvium soil. The superstructure is modeled as a single-degree-of-freedom (SDOF) oscillator with Modified Clough stiffness degrading model resting on flexible soil. The soil beneath the superstructure is considered as a homogeneous elastic half space and is modeled through the concept of Cone shallow foundation Models. A parametric study is carried out for 2400 soil-structure systems with various aspect ratios of the building as well as non-dimensional frequency as a representative of the structure-to-soil stiffness ratio having a wide range of fundamental fixed-base period and target ductility demand values under a family of 19 earthquake ground motions. Results show that generally for the structure located on softer soils severe dissipated energy drop will be observed with respect to the corresponding fixed-base system. The only exception is for the case of short period slender buildings in which the hysteretic energy demand of soil-structure systems could be up to 70% larger than that of their fixed-base counterparts. Moreover, dissipated energy spectra are much more sensitive to the variation of target ductility especially for the case of drastic SSI effect.

Sleep deprivation, weighted road march combined with short term high intensity physical activities are important aspects of army ranger operations, which can lead to inflammation, muscular injury, and physical and shooting performance loss. On the other hand, animal and human studies documented that choline supplement relieves inflammation and improves physical and mental performances. The aim of this study was to examine the effect of choline supplementation on serum creatine kinase and IgA, macular endurance, and shooting accuracy of army rangers following one-day simulated operation.
Twenty army rangers voluntarily participated in this double-blind, placebo controlled quasi-experimental study. The subjects were divided to 2 equal groups and randomly assigned as choline (n = 10, age = 21.2 ± 3.2 years, Vo2max = 37.7 ± 4.9 mL/kg/minute) and placebo (n = 10, age = 21.2 ± 2.2 years, Vo2max = 38.7 ± 6.6 mL/kg/minute) groups. Choline supplement (2 gr choline bitartrate/day) or placebo (a tea spoon of acid citric/day) was administrated one week before the day of simulated operation, which included partial sleep deprivation (22 p.m.-1a.m.), 19.3 km weighted (12 kg) road march, and 4.8 km competitive run test without extra weight. Serum CK and IgA, muscle endurance (upper body, lower body, and abdomen), and shooting accuracy were assessed before and on the day following the simulated operation. The data were analyzed using independent samples T test (subtracting pretest from posttest) and paired samples t test.
There were no significant changes in serum CK and IgA, abdominal muscles endurance and shooting performance in choline and placebo treatments from pre to the post test, while the posttest upper and lower body endurances were significantly (P The results of this study showed that choline supplement does not induce any positive effects on post operation outcomes of inflammation, muscle injury, muscle endurance, and shooting accuracy.

Wheelchair basketball players rely on upper body strength. It is well established that strength training potentiates muscle hypertrophy and improves strength. But the anabolic and catabolic effects of upper body strength training have not yet been studied in female wheelchair basketball players. Therefore, the aim of this study was to investigate the effect of a 8 week upper body strength training on serum IGF-1 and cortisol, and performance in female wheelchair basketball players.
18 female wheelchair basketball players volunteered (age=29.51±2.6 years, weight =66.35±14.59 kg) to participate in this study. They were randomly assigned into either a control (regular wheelchair basketball training) or an experimental (regular wheelchair basketball training upper body strength training) group. Either group participated in an 8week training program. Pre and post exercise serum IGF-1, cortisol and also performance tests results were analyzed using independent t- test, dependent t- test and covariance.
There were no significant differences between group in post-test IGF-1 , cortisol and performance test( penalty shoot, left and right side shoot and three point shoot), except baseball style throwing which was significantly better in the experimental group than the control(P Based on these results it can be said that upper body strength training can improve strength dependent skills in wheelchair basketball players, but does not result any significant anabolic and catabolic effects.

Pre-cooling is known to enhance exercise performance in soccer players. However, little information currently exists regarding precooling effects in Iranian young soccer players..
The aim of this study was to assess the effect of precooling (water immersion) on exhaustive performance in the heat ( temperature = 32 - 34°C, humidity = 50%)..
Patients and Sixteen young male soccer players from the provincial competitive teams were divided into two equal groups and were randomly assigned to precooling (age = 16.5 ± 1.1 year, height = 171.7 ± 6.4 cm, BMI = 21.5 ± 3.3, VO2max = 50.6 ± 6.9 mL/kg/min) and non-precooling (age = 16.1 ± 1.1 year, height = 170.0 ± 4.7 cm, BMI = 21.3 ± 3.6, VO2max = 50.6 ± 6.8 mL/kg/min) groups. An exhaustive treadmill run test was conducted after warm-up (non-precooling) or warm-up water immersion (temperature = 22 - 24°C). Oral temperature, plasma lactate and plasma volume were measured at the baseline (fasting state), mid test (immediately after warm up or warm -up water immersion) and post test (immediately after exhaustive test). Mixed repeated measures analysis of variance and independent t test were used for data analyzing. P There were no significant differences between two groups at baseline, mid test and post test regarding oral temperature and plasma lactate. The time to exhaustion was considerably higher in the precooling group compared with the non-precooling group, but the difference was not statistically significant. No significant differences were found between the two groups on measures of the baseline and mid test plasma volume, but post test plasma volume was significantly higher in the precooling group compared to the non-precooling group (P These results show that precooling effectively attenuates dehydration, but has no positive effect on exhaustion time in the hot environment..

For many years gradualtapering was done. New theories with an emphasis on two-stage tapering Suggest that the load of training reduced gradually and then a few days before the race, the load of training rise again. Therefore the aim of this research is Study the effect of two-stage tapering in compare with gradualtapering on serum lactate, testosterone and cortisol in male swimmers. In this semi-experimental study 12 young male swimmers (with age ranging from 14 to 17 years) as available sampling were selected. Subjects based on their final record were divided in to two groups: two-stage tapering group (N = 6) gradualtapering group (N=6). Before and after the completion of 2 weeks tapering Program, performance test and blood samples were taken for assessment serum levels of lactate, testosterone and cortisol. To evaluate the result paired T-test and ANCOVA (analysis of Covariance) were used. after 2 weeks of tapering program, in two-stage tapering group compared with pre-test, serum levels of lactate and cortisol was increased significantly (P>%5). But in gradualtapering group compared with pre-test, serum levels of cortisol was increased significantly (P> %5). changes in serum lactate and testosterone levels in two-stage tapering group compared with gradualtapering group was not significant (P> %5). While increase in serum cortisol levels in two-stage tapering group compared with gradualtapering group was significant (P> %5). Generally it can be said, that likely two-stage tapering strategies compare then gradualtapering strategies have more catabolic effect.

It is well known that exercise training has positive effect on catecholamine response to a given work load. But in this regard, the effective method of training needs to be studied. The aim of this study was to compare the effects of 8 weeks endurance exercise with two overloading patterns on the left ventricular catecholamine levels. 29 male Wistar rats were randomly assigned to control (n = 9), daily sinusoidal overloading (n = 10) and weekly sinusoidal overloading (n = 10) groups. After the last exercise session, left ventricular blood samples were obtained immediately after lactate threshold test. Plasma concentrations of adrenaline and noradrenaline were measured by ELISA method. One way analysis of variance was used for analysis of the data. Immediately after lactate threshold test, adrenaline level was significantly (P < 0.05) lower in weekly loading group than in control and daily loading groups. Adrenaline was higher in the daily loading group compared with control group but did not reach the significant level. Noradrenaline levels were not significantly (P > 0.05) different between three study groups. The results showed 8 weeks of endurance exercise with weekly sinusoidal overloading pattern could induce a lower adrenal medulla activity (reflection of physical and physiological improvement) than daily sinusoidal loading pattern in response to the same absolute work load.

Leptin is a polypeptide that is correlated with body weight changes and energy consumption and affected by exercise training. The aim of the present study was to determine the effect of 6 weeks resistance training on body composition, serum leptin and muscle strength in non-athletic men. In this semi-experimental trial, 22 non-athletes male living in dormitory of Zanjan University, who were enrolled in 2011-12 academic year were selected with purposive sampling method and randomly assigned to experimental (n=12) and control (n=10) groups. The experimental group performed training program based on the protocol of Kramer and Ratns for 6 weeks (3 sessions per week). At the beginning and end of the research, muscle strength, body composition and serum leptin were measured. Serum leptin was measured by ELISA. Independent T and paired T tests were used to analysis the data in SPSS 16 software. After 6 weeks of strength training, changes in serum leptin levels and body composition (fat mass without fat) between the two groups was not statistically significant (p>0.05). But in experimental group, the upper and lower body strength training was significantly increased compared with pre-test in control group (p<0.05). It seems that no significant changing in serum leptin levels after a period of resistance training is due to no changing in body fat and not enough exercise, but this training cause in increasing muscle strength.

Animal studies have reported very useful properties including weight loss and improved body composition for conjugated linoleic acid (CLA). However, there is limited information about the combined effect of resistance training and CLA supplementation. Therefore, the effect of CLA supplementation and resistance training on body composition, serum leptin and muscle strength in non-athlete men was examined in this study. In a quasi-experimental trial with double-blind design, 23 non-athlete men were randomly assigned to two groups: training + supplement (n=11), and training + placebo (n=12). Both groups performed 6 weeks (3 sessions per week) of resistance training program based on the Kramer (2004) protocol. The experimental group received 3 capsules (1000 mg) of CLA supplement and the control group ingested 3 capsules of placebo (olive oil) per day. Muscular strength, body composition and serum leptin were measured in the beginning and at the end of the study. Data were analyzed using dependent and independent t tests. Based on the findings, CLA + resistance training supplementation significantly decreased fat mass and serum leptin and significantly increased non-fat mass compared with placebo + resistance training (P˂0.05) while the lower and upper body strength of both groups were not significantly different. According to the results, it can be stated that resistance training combined with CLA supplementation can improve body composition and decrease serum leptin in non-athlete men. But it does not necessarily lead to a significant improvement in lower and upper body strength.

A previous cross-sectional study found reduced lung function among over weight and obese students in Zanjan city. However, there is no reliable evidence about the respiratory function of underweight and normal weight students. The objective of this study was to evaluate lung function and develop prediction equations in underweight and normal weight female young adults residing in Soltanieh city near Zanjan. A cross sectional study was conducted on underweight (n=29, mean age=16±0.84 years) and normal weight (n=38, mean age=15.9±0.86 years) sedentary female young adults. Fat mass (FM) was measured by Omron Body Fat Monitor FB-3002. Lean body mass (LBM), waist to hip ratio (WHR), body mass index (BMI) and waist circumference (WC) were calculated. Maximum oxygen uptake was calculated using Queen’s College step test. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were recorded, using Spirolab III spirometer. Independent t test, Pearson’s correlation test and stepwise linear regression analysis were used for data analysis. FVC and FEV1 were significantly lower than the reference values in both groups (P<0.05). LBM was significantly correlated with FVC and FEV1 in underweight and normal weight groups (P<0.05). Regression equations were derived to predict FVC and FEV1 using LBM. This study suggests that dynamic lung functions are poor in underweight and normal weight sedentary female young adults residing in Soltanieh city and LBM plays a significant role in their lung function.

Endurance training improves the activity of G4 type acetylcholine esterase (AchE) in muscle fibres. The purpose of this study was to investigate the effects of 8 weeks of endurance training (ET) on activity of A12 type of AchE in Flexor Hallucis Longus (FHL) and Soleus (SOL) muscles of rats. Sixteen male Wistar rats (age: 10 weeks, weight: 172.17±10.080 gr), were randomly divided in 2 groups (control; N=8 and ET; N=8). Training group carried out 8 weeks (5 session/week) of endurance training on animal treadmill with speed of 10 m/min for 30 min at the first week. Forty eight hours after last session of training, FHL and Sol muscles of animals were moved out under sterilized situation by cutting on postero-lateral side of hind limb. For separating AchE subunits, homogenization and electrophoresis (0.06 non-denaturaing polyacrilamide) methods were used. AchE activity was measured by Elisa kit. Independent t-test showed that the activity of this protein significantly (p=0.017) increased in SOL muscle of ET group by 119%, but did not changed in FHL. In both groups (ET and Con), FHL muscle had significantly (ET: p=0.028 and Con p=0.01) higher basic levels of AchE activity compared to SOL muscle. This significant increase in AchE of SOL might be indicative of responsiveness of AchE of this muscle following endurance training for improving acetylcholine (Ach) cycle in neuromuscular junction. Endurance training might increase the A12 type AchE activity to improve the Ach cycle as part of the adaptation of neuromuscular junction to increased level of physical activity.

This study aims to evaluate the effect of choline supplement on the changes in the free fatty acids of plasma and fats metabolism at the end and recovery period of a long exercise session in men who are elite in the triple sport courses (age: 21.44±2.83, weight: 54.71± 5.34 kg, and maximal oxygen consumption: 71.25 ±4.36 ml kg -1 min -1). Nine elite triathle men had two 120 minutes sessions of running on a treadmill with an intensity of 59 to 64% VO2MAX in a one blind crossover design study. Subjects took the placebo one hour before the first activity session, and Choline Bitarterate supplement one hour before the second activity session. Blood sampling was performed before the start, end and half an hour after the end of activities in order to measure the free fatty acids of plasma; the colorimetric method was used in order to measure this characteristic. Data were analyzed by the repeated ANOVA (analysis of variance) test at the significance level (P≤0.05). Comparison of two session results showed that the level of plasma free fatty acids at the end of activity levels of in the activity and with the choline supplement was significantly lower than the same value in an activity with placebo, but in the Recovery period, the activity with choline supplement was significantly higher than the same value in activity with placebo. It was concluded that taking the choline supplement could increase their consumption in the muscle cells and thus the rate of fat oxidation during the long-term sports activities by facilitating the transfer of plasma free fatty acids from the plasma membrane.

Based on the World Health Organization (WHO) proposition, 5 days a week and 30 minutes a day of aerobic physical activity has numerous healthy effects for middle-aged and adult population. However, to date the anti inflammatory effect of this program has not been studied. The purpose of this study was to investigate the effect of 16 weeks of the WHO purposed physical activity program on C-reactive protein and interleukin-6 in middle-aged men. 30 middle-aged men with C-reactive protein and interleukin-6 levels higher than the predicted values participated in this study. The subjects randomized to three groups: control(n=10), one training session per day(n=10, 16 weeks, 5 days a week, 30 minutes a day tread mill running, with70-80% of HRmax), and two training sessions per day(n=10, 16 weeks, 5 days a week, 2×15 minutes a day tread mill running, with70-80% of HRmax). Pre and post exercise C-reactive protein (fasting), interleukin-6(fasting), BMI and VO2max were measured. Data were analyzed with paired and one sample t-test and variance analysis. Both training methods caused significant (p<0.05) decrease in C-reactive protein, interleukin-6 and BMI, and significant (p<0.05) increase in VO2max in comparison with the control group. 16 weeks of the WHO proposed physical activity program, either one session per day or two sessions per day, can lead to C-reactive protein and interleukin-6 reduction in middle-age men.

In healthy teenagers, obesity and physical inactivity are the two main factors that affect respiratory function. The aim of this study was to evaluate the effect of aerobic exercise training on improving lung function in overweight and obese students. Thirty overweight or obese subjects with poor endurance performance and mild deterioration of respiratory indices (forced expiratory volume and forced expiratory volume in 1 second < 90% predicted) were randomly assigned into control (age: 16.6±0.83 years, height: 167±5.05 cm, weight: 80.44±7.65 kg) and intervention groups (age: 16.5±0.83 years, height: 166±6.7 cm, weight: 79.62±9.33 kg). The intervention group preformed 24 weeks of continuous treadmill running (3 days a week). Respiratory indices were measured pre, mid and post exercise. Independent t test, paired t test, Pearson's correlation test and repeated measure were used for analyzing the data. In the intervention group, post exercise respiratory indices were significantly higher than the pre exercise values, and did not reach the predicted values. No significant differences were found in pre, mid and post exercise respiratory indices in the control group. In the intervention group, improvements in respiratory indices were positively correlated with maximum voluntary ventilation (MVV) improvement but not with BMI reduction. No significant differences were detected between the 2 groups in terms of pre, mid and post exercise measures of BMI, weight, height, and respiratory indices. In overweight and obese teenagers, appropriate aerobic exercise training can partly improve lung function by strengthening the muscles of respiration. However, in order to achieve the predicted values of lung function, a further increase in activity duration and decrease in BMI is necessary.