Journal of Sport Biosciences
Year:2011 | Volume:- | Issue:7|Papers Count:11

Energy drink consumption by athletes has become increasingly popular. The aim of this study was to determine the effect of phantom and dragon energy drinks on female athlete students. For this purpose, twelve female athlete students of Tehran University (age 22±0.63 years, height 162.1±5.8 cm, weight 56.91±6.79 kg) volunteered to participate in this study and performed three sessions of a Bruce treadmill test with 4-day intervals. In each session, in a double-blind, randomized and counterbalanced design, 6 ml/kg/bw of phantom, dragon or placebo was consumed 40 minutes before the exercise test. Results showed that dragon and phantom consumption resulted in a significant difference between VO2max, time of exhaustion and perceived exertion in the posttest (P<0.05). There was no significant difference in pretest HR between the two drinks (p>0.05). Dragon significantly increased HRmax when compared to phantom and placebo (P<0.05). In conclusion, the acute consumption of phantom and dragon drinks probably has ergogenic effects on some cardiovascular factors.

Research has shown that chronic, long and exhausting endurance training programs cause iron deficiency. This problem can have a negative effect on physical performance. The aim of this research was to study the effect of endurance training and iron supplement on anemic indexes [hemoglobin (Hb), hematocrit (HCT), red blood cell (RBC), total iron binding capacity (TCBC) and ferritin], and cytochrome C oxidase (COX) enzyme in male rats. Forty male wistar 4848 rats with an average weight of 321.55±22.67 were divided into four groups: experimental group I, experimental group II, control I, and control II. Experimental group I were trained to perform endurance running on a treadmill for 12 weeks (with an intensity of 32 m.min-1 for 60 minutes every session, five sessions a week) (T). Experimental group II received 800 micrograms of iron supplement (ferrous sulfate) daily (gavage) in addition to being trained to perform endurance running on the treadmill (Ti). Control group I were sedentary (inactive) for 12 weeks (S) and control group II did not perform any exercise but received iron supplement as did experimental group II (Si). After 12 weeks, rats were killed by the easy method. Blood samples were analyzed for anemia indexes in the laboratory. Muscle soleus COX was measured by cytochrome C oxidase assay kit. The data were analyzed by oneway ANOVA with (P<0.05). Statistical analyses showed a disorder in the capacity of iron resources in the sample. On the other hand, the consumption of iron supplement not only improved anemia indexes but also increased the activity of COX in Ti group. But iron supplement had no positive effect on inactive (sedentary) sample. The most important conclusion is that iron supplement is very useful and effective for subjects with iron deficiency.

The aim of this study was to determine the effect of 6 weeks of aerobic training and L-carnitine supplement on body fat percent and serum lipid profiles in active men. The method used was semi-experimental. Eighteen active men were selected voluntarily and randomly divided into two groups of experimental (nine individuals with the average age: 44.4±8 years, weight: 8.2±16.6 kg, height: 173±6 cm, BMI: 26.9±4.8 kg/m2) and control (nine individuals with the average age: 48.8±8 years, weight: 82.8±9.5 kg, height: 169±0.05 cm, BMI: 29±3.8 kg/m2). Both groups performed aerobic training based on the principle of overload for 6 weeks. During this period, the experimental group consumed 10 mg/kg/day L-carnitine orally (average less than 1 gram/day) and control group ingested 2.5 mg/kg/day B1 vitamin as placebo. Before and after aerobic training, blood samples were gathered. In addition, aerobic power and body composition were measured. The data were analyzed using Kolmogorov Smirnov, paired, independent t test and ANCOVA. The results showed that aerobic training and L-Carnitine supplement significantly reduced body fat percent (P<0.05), but they had no significant effect on serum triglyceride, total cholesterol, LDL-C and HDL-C. We concluded that if middle age men would like to reduce their body fat percent, they can use L-carnitine supplement with low dosage along with aerobic training. However, determining positive effects of aerobic training and Lcarnitine supplement on serum lipid profiles needs further investigation.

The aim of this study was to investigate the response of vascular endothelial growth factor (VEGF) to a bout of exhausted submaximal exercise and its correlation with VO2max in different bouts. Therefore, 12 active men (mean age: 24 years) were randomly selected and performed the submaximal exercise. Blood samples were collected before, immediately and two hours after the exercise training. Data were analyzed using one-way ANOVA and Pearson correlation coefficient (a=0.05). Serum VEGF increased significantly immediately (p=0.000) and two hours after the exercise (p=0.000). In addition, there was no significant relationship between serum VEGF and VO2max before the exercise training (p=0.352) while there was a significant relationship immediately (p=0.006) and after two hours (p=0.026) after the exercise. In conclusion, one bout of exhausted submaximal exercise can be a stimulus to increase angiogenic factor of VEGF and the more the subjects’ aerobic power, the more they might experience angiogenesis.

Overweight and elevated BMI can increase the risk of breast cancer in postmenopausal women. On the other hand, it seems that exercise training affect weight and BMI. The aim of this study was to investigate the effects of exercise training on some anthropometric variables in postmenopausal women with breast cancer. Thus, 29 postmenopausal women with breast cancer who received surgery, chemotherapy and radiation-therapy were divided into two groups, intervention and control. Subjects of intervention group performed 15 weeks of exercise training including walking (2 sessions per week) and resistance training (2 sessions per week, different from walking days). Before and after 15 weeks, weight, BMI, WHR, Vo2max, blood pressure and rest heart rate were measured in two groups. Data were analyzed using ANOVA. Results indicated significant differences in weight, BMI, WHR, Vo2max and rest heart rate between intervention and control groups (p<0.05). In fact, exercise training had significant effects on the weight, BMI, WHR, Vo2max and rest heart rate in postmenopausal females with breast cancer. However, there was no significant difference in blood pressure between the two groups. Therefore, exercise training can improve maximal aerobic capacity, rest heart rate and some anthropometric variables in postmenopausal women with breast cancer.

Physical fitness is considered as a key component for optimal performance in most sports. The aim of this study was to investigate neuromuscular and functional adaptations to two different training methods. For this purpose, 14 male volunteers were divided randomly into two groups. Group A (plyometric) trained with plyometric training and group B (combined) trained with traditional resistance training combined with plyometric training 3 days per week for 8 weeks. To evaluate muscle neural activity, before and after training programs, surface EMG was performed on vastus lateralis muscle. Also, to determine muscle strength and power, agility and speed of movement, 1RM, Bosco, Sargent jump, Hexagonal Obstacle and 35 m dash tests were used, respectively. Paired t-test and independent t-test were used to identify any significant differences (p£0.05). Results showed that SEMG increased in both groups (plyometric group 30.27%, p£0.11; combined group 43.78%, p£0.05). In Bosco, Sargent jump, Hexagonal Obstacle and 35 m dash tests, plyometric group had better results than combined group but in 1RM test combined group had better results than plyometric group. It can be concluded that possibly, for short-term periods (8 weeks), plyometric training alone would be more effective than combined training (resistance and plyometric) in targeted exercise performance.

The present research was performed to investigate the effects of aerobic dance with different durations on salivary cortisol and testosterone, and consequently on the mood and body mass of inactive young women. The design of the research was quasi–experimental and the sample consisted of 19 inactive young women (mean age: 30±3 years, height: 167±5.1 cm, weight: 65.5±7.4) who were randomly divided into two groups: experimental (N=12) and control (N=7). The experimental group performed aerobic dance for 8 weeks with the intensity of 120 metronome strokes. Salivary cortisol and testosterone of all subjects were collected five times during the as well as before and after the dance. A dose of 6 ml salivary solution was obtained before and after the exercise. One–way repeated ANOVA with SPSS were used to analyze the data. The Spearman correlation coefficient was used to determine the relationship among the variables. The findings showed that testosterone concentrations decreased after the exercise and during rest. However, cortisol concentrations increased after the exercise and during rest. Positive relationships were observed between mood and testosterone concentration after the first session. The same result was obtained for cortisol after the sixteenth session. The mood variable had six subcategories out of which only two measures were found to be related with the period of exercise. The final conclusion of the study was that hormonal responses were related to the duration of the aerobic dance exercise. It is suggested that young women be more active and perform daily exercises especially aerobic dance to avoid depression and to be able to feel happier.

The aim of this study was to investigate the effect of 8 weeks of selective exercise activity and estrogen supplement on satellite cells in ovariectomized sprague-dawley rats. At first, subjects were ovariectomized and after one month of complete recovery, they were randomly divided into four groups: Control, Exercise activity, Estrogen supplement, and Exercise and Estrogen supplement. Only exercise and exercise and estrogen groups performed a selective exercise activity for 8 weeks and during this period, estrogen and exercise and estrogen groups were implanted subcutaneously with 0.6 ml estrogen supplement. The obtained data were analyzed using one-way ANOVA. The research results indicated that exercise activity group showed a 1.5 times increase in the number of satellite cells while in exercise and estrogen and estrogen groups they decreased by 68% and 73.9% respectively. Moreover, obtained results demonstrated that observed changes in the number of satellite cells were significant only in exercise group. the proliferation of satellite cells in the soleus muscle of rats. This increase in the number of satellite cells is the result of function of the distance running. This study indicated that endurance training can be used as a precondition for increasing muscle volume and improving muscle function.