OLYMPIC
Year:2008 | Volume:16 | Issue:3 (SERIAL 43)|Papers Count:12

Studies have shown that exercise can increase bone density, but there is still uncertainty about the type and the intensity of exercise that provides maximum anabolic stimulus to bone (6). The purpose of this study was to investigate the longitudinal effect of endurance, sprint and resistance activities on bone density in male elite athletes compare with non athletes.Subjects comprised 30 elite, male athletes (10 endurance runners 3000 and 5000 m,10 sprinters 100 and 200 m, 10 body builders) and 10 non athlete controls aged 20-30 years. They were selected on the basis of the availability. Bone mineral density (BMD) of the lumbar spine and femoral neck was measured by DEXA. Data analyzed using descriptive and inferential statistics (ANOVA and LSD post Hoc a=0.05).Compared with controls, body builders and sprinters showed significantly higher BMD, While endurance runners showed significantly lower BMD at the lumbar spine and femoral neck (P£0/5). Also, compared with sprinters, body builders showed significantly higher BMD, While endurance runners showed significantly Lower BMD at the both measured region (P£0.5).Our results provide further support for the concept that bone response depend the type and Mode of exercise.

The purpose of this study was to determine the effect of sprint training and detraining period, on sICAM-1, novel inflammatory markers the predictive of cardiovascular disease in wistar rats. For this reason 42 male rats divided randomly in two groups: sprint training group (experimental) (n=24 & Weight 210±7) and control group (n=18 &Weight 211±3). Exprimental group trained for 12 weeks, 3 times in a week (between 80-100 & higher100% Vo2max). Six trained rats experienced the detraining, so that the effects of detraining studies. after 24 sessions of training. The blood sampling were draw in different phases of training. sICAM-1 measured with ELISA kits for rat (R & D systems). Data were analyzed by Kolmogrov-Smirnov ,one way anova, repeated measures, LSD and t tests. The results showed that sICAM-1 levels were increased insignificantly (P=0.079) in the first 8 weeks and showed increased significantly (P=0.004) after 12 weeks. Meanwhile, it was certain that, by to stop of intensity sprint trainings, showed decreased insignificantly (P=0.152). Whereas showed significant difference between training and detraining groups (P=0.024). Generally, sprint training leads to an significantly increased for sICAM-1 and the body defensive system change during exercising and the body exposed to the dangers of atherogenesis inflammatory harms.

Myostatin, a potent negative regulator of skeletal muscle growth, play important role in the regulation of muscle mass. However, the mechanisms by which muscle myostatin production is regulated have not been fully understood. The purpose of this study was to determine the effect of eight weeks resistance training on changes of serum myostatin, cortisol and testosterone levels, muscle strength and lean body mass in untrained young men. Sixteen young men (age: 22.5±2.9 yr) were assigned to resistance training (n=8) or control (n=8) groups. The training protocol consisted of thrice weekly using three sets of eight to ten repetition at 60-70% of 1RM for whole-body exercise, whereas control group performed no resistance training. Blood sampling, muscular strength test and body composition analysis (DEXA), were performed at 0, 4th and 8th weeks. One-way ANOVA with repeated measurement and bivariate correlation showed that resistance training caused significant increase in muscular strength, lean body mass and testosterone, whereas cortisol and myostatin were decreased (P<0.05), and there were also negative and positive correlations (r=-0.69, P<0.05) between changes of serum myostatin with testosterone and myostatin with cortisol after resistance training, respectively. These data demonstrate that serum myostatin levels are reduced in response to resistance training, and resistance training-iduced alterations in myostatin, testosterone and cortisol levels may have a role in increases muscle strength and mass.

Elevated circulating estrogens, especially estradiol and a sedentary lifestyle increase the risk 0f breast cancer. The purpose of the present research is to examine the effect of selective aerobic exercise with moderate intensity on serum 17b-estradiol and changes of obesity measures in postmenopausal women. Therefore thirty two sedentary, postmenopausal women with the age of 54±7 years, height 158±7 (cm) and weight 73±8 (kg) participated in this study as subjects and then they were divided randomly in to experimental (n=17) and control (n=15) groups. Serum 17b-estradiol with Electrochemiluminescence, body mass index (BMI), percent body fat (PBF) and waist to hip ratio (w: h) were once measured at baseline and then they were measured after ten weeks of selective aerobic exercise (60-70% max heart rate). Variations of characteristics in each group were done by t-test (dependent) after 10 weeks and variation between dm (differences means) of characteristics exercise and control group were compared by t-test (independent) and the effect of body mass index, percent body fat and waist to hip ratio at 17b-estradiol concentration changes were examined by two recreations. There was significant decrease of selective exercise on 17b-estradiol concentration (p=0.038) and BMI (p=0.004). There were statistically significant differences between exercise and control differences meant in BMI and 17b-estradiol changes from base line to 10 weeks of selective exercise (p<0.05). There were no significant effect of BMI and %BF and W: h changes on 17b-estradiol changes from baseline in 10 weeks. Therefore, selective aerobic exercise with moderate intensity, independent of obesity, decreases 17b-estradiol concentration in the serum of postmenopausal women. That it can be considered as a factor in preventing the occurrence of breast cancer in women.

The purpose of this study was to determine of short term detraining on aerobic and anaerobic power and maximal strength and body fat percent after endurance, resistance and concurrent training period. 32 untrained healthy young men (24.93±1.26 years old, height 175.78±7.07 cm and weight 72.03±11.26 kg) have participated in three training groups including: endurance (n=12), resistance (n=9) and concurrent (n=11) for 8 weeks. The training of endurance group included running on the treadmill (65%-80% maxHR, 16-30 min) and resistance group did weight training (65%-85% 1RM). Training program for concurrent group was a combination of endurance and resistance groups. Vo2max and anaerobic power were estimated by George test and Wingate test and upper and lower body maximal strength and body fat percent in three point were estimated in three stages including initial test , pretest (after the training period), and post test (after 8 weeks of detraining). From ANOVA with repeated measures and Bonfrroni and LSD test were used for within group comparison, as well as ANOVA and Tukey test were used for between group comparison (p<0.05).After 8 weeks of detraining in endurance group there was a significant decrease in VO2max , lower body absolute strength (squat) and upper relative strength (bench press) and a significant increase in body fat percent (p<0.05).Further more, detraining in resistance and concurrent group caused significant changes in VO2max, upper body and lower body absolute and relative strength and body fat percent (p<0.05). In between groups comparisons, there was no significant difference between percent of variables among three groups (p>0.05). Finding indicated that the combination of endurance and resistance training does not lead into a difference regarding accepted adaptation, too.

The purpose of this study was to comparison the electromyographic and electroneurographic parameters including IEMG, Amplitude, Nerve Conduction Velocity, and latency in three groups of athlete (elite and amateur) and nonathlete, to analyze the probable motor – neural adaptation and the time of occurrence of the adaptation following the strength training. Subjects (18-24 old years males) divided in three groups: Professional body builders (n=10, with at least 2 years of training experience), Amateur body builders (n=10, who had 3-4 month training experience), and Control group (n=10, without any training experience). To analyze the neural adaptation, electromyographic parameters (IEMG) in maximal voluntary isometric contraction (50%) was measured in order to record the motor activation in prime mover muscles of biceps. Also electronorographic parameters measured by musculocutaneous nerve electric stimulation of biceps. Analyzing the data by One Way ANOVA showed: There were no significant changes in IEMG (p=0.34), N.C.V (p=0.36) ,and Latency of signal (p=0.11) among groups, but there was significant difference about Amplitude (p=0.04) that indicated weight training influences on recruitment and frequency of motor units.

Up until now, it was considered that the weakness of lumbopelvic girdle muscles is the cause of lumbar lordosis variation with effect on pelvic tilt and lumbar vertebras. But, it became dubiousness by some of recent researches. Therefore, the aim of this study was to investigate the relationship between strength of lumbopelvic girdle muscles with lumbar lordosis. In this research, one hundred seven healthy and non-athlete students were chosen from general class of Tehran University as samples randomly. The average of age, weight and height of the samples were 21.85±1.75 years, 70.88±10.50 kg, and 177. 12±6.16 cm. The strength of muscles was measured by Digital Dynamometer and Double Straight Leg Lowering (DSLL) test. Also, the lumbar lordosis angle was measured by Flexible ruler. The strength average of lumbar extensors, hip flexors, hip extensors and abdominal muscles were 52.96±20.17 kg, 22.12±5.73 kg, 15.56±4.46 kg, and 38.04±7.51 degree respectively. Collective data were analyzed using descriptive statistic and correlation between parameters. The results did not indicate a significant relationship between the strength of lumbopelvic girdle muscles and lumbar lordosis (P>0.05). Therefore, on the base of collective data, it seems that the focus should not be concentrated on the weakness or strength of single muscle groups, but all muscles groups engaged in this region must be accounted for.

Despite of young and adolescence intent to the boxing sport, because of dominant aggression and directly blows contact to head, face and central nervous system, it was continuously criticized in to the different groups .The groups of sporting and physician conventions were distinguished boxing with physical and neuropsychological disorders and some groups believed that the side effects of this sport weren’t more than of all others. For this base the aim of this study was to investigation on the neuropsychological aspects of amateur boxers in Qom city. Subjects lies in the 3 groups that each groups contain 20 subjects: The first group was amateur boxers with 4 years minimal activity (directly has been presented to the head blows), second group was amateur soccer players with 4 years minimal activity (has been presented to the not very severe head blows), third group was non athlete subjects. The groups were homogeneous in weight, high, age and education. To understand brain disorder interview by medicine method has been used, then Wiskancin, Bonardele, Bender geshtalt, Kim karad visual memory, Benton and wechler memory (Alef type) tests has been performed. The homogeneity of between group variances was gained by the statistical method. Also between structural – visual abilities neuropsychological aspect in groups, significant difference has been gained (p=0.000). In Kim karad visual memory test at the mild and long term visual memory, significant differences between three groups was observed (p= 0.000, P=0.009), that least score has been belonged to the boxers. Generally can say that: one bout of four years amateur boxing sport can effect significantly on boxer disorders in visual perception, memory and spatial orientation.

Although the full purpose and functions of sleep are stil unclear, it is well established that sleep deprivation can result in significant impairments in human cognitive and motor functioning. Response time and accuracy are major component of sports events and many games skills. In order to students and athletes in period of works with several reasons deprived from sleep for a night. This study examined the effect of 24h sleep deprivation on response time & Basketball jump shot accuracy of physical education male students at Shahrood University of technology. Participants (N=26) with average age 22.61±2.14 year, are sampled in two (experimental & control) group. Experimental group (N=13) was kept awake for 24h & control group spend this time normally. Two groups tested with Nelson's response time & AAHPERD basketball jump shot accuracy test before and after 24h period. Independent compare mean (t) of basketball jump shot and response time tests revealed that: there are no significant differences (p³0.05) between two groups in post test & also paired t test revealed that no significant differences (p³0.05) between pre & post tests of groups. This study showed that 24h sleep deprivation is not influence response time and shooting accuracy of students.

The overall aim of this study was to investigate the effect of, and the interaction between, the diurnal and circamensual variation on cardiorespiratory system. Twenty eumenorrheic females (age 21.5±2.5 years, height 1.64±1.03 m and weight 57.2±4.8 kg: mean±SD) took part in this study. All subjects reported a history of normal menstrual cycle lasting 26-32 days and none had used any form of oral contraceptives and Hormonal drugs for at least 4 month before entering the study. To deal with a possible “ first experiment effect”, all subject underwent two familiarization session in order to minimize learning effects and increase reliability of measurements as has been done in some proceeding work to the experimental work. For main testing, subjects attended the laboratory at 06:00 h and 18:00 h during the two phases (follicular and luteal) of the menstrual cycle. Body temperature was measured during 30 min before the tests in the standard position. Cardiorespiretory indicators (heart rate and blood pressure) was measured before and after activity. In addition, maximal oxygen consumption (vo2max) was assessed by Bruce incremental treadmill. Two way repeated measures ANOVA (time of day×cycle phase) was used to examine the effect of time of day and phases of the menstrual cycle and interaction effects of circadian rhythm and menstrual cycle on Cardiorespiretory Functions . Also 1- Sample KS test was used to normality of distribution. Body temperature increased significantly from 06:00 to 18:00 by 0.8oC (F=183.43, P=0.000). There was found a significant difference in time of day on Vo2max (F=38.71, P=0.000), at 18:00 was 2.6 ml/min greater than 06:00 h. A time of day effect also was significant for heart rate before (F=42.01, P=0.000) and after (F=10.32, P=0.005) activity which at 18:00 h was respectively 8, 4 rate per min greater than 06:00 h. Diurnal variation also was observed for systolic blood pressure before (F=16.04, P=0.001) and after (F=6.09, P=0.023) activity which at 18:00 h was respectively 6, 4.8 ml. hg lesser than at 06:00h. A significant circamensual variation was observed for body temperature (F=38.97, P=0.000), heart rate before (F=12.59, P=0.002) and after (F=5.51, P=0.030) activity with values greater in luteal phase. In addition, vo2max (F=59.62, P=0.000), and systolic blood pressure before (F=9, P=0.007) and after (F=5.13, P=0.035) activity showed circamensual variation, but values were greater at follicular compared to luteal phase. Interaction effects between time of day and menstrual phase was observed just on body temperature (F=37.13, P=0.000). The present results suggest that female’s cardiorespiratory indicators has been affected by time of day and menstrual cycle phases. Therefore diurnal and circamensual variation should be taken into account when measuring body temperature and cardiorespiratory indicators. Therefore, in studies of females should be carefully controled circadian rhythm and circamensual variation.