Journal of Sport Biosciences
Year:2013 | Volume:5 | Issue:3|Papers Count:12

The present study aimed to determine the effects of 12 weeks of aerobic exercise in different times of day on some cardiovascular risk factors in overweight men. 40 non-athletes, overweight men with an average age of 22.25±2.45 years old and BMI of 30.06±2.42 kg/m2 were randomly allocated to four groups of morning and evening aerobic training and control. Morning and evening training groups performed the aerobic training protocol three sessions per week for 12 weeks with 75 to 85 percent of maximal heart rate and 15 minutes training per session. The training time was increasingly added 1.5 minutes every three sessions until the training time reached 30 minutes. The control groups were instructed not to do the training program during the research period. Blood samples (5 cc) were taken from the participants at the beginning of the research period, week 6 and the end of week 12 in order to measure cardiovascular risk factors (i.e. triglyceride, low density lipoprotein, high density lipoprotein and cholesterol). The obtained data were analyzed using analysis of variance (ANOVA) and t-test with the Bonferroni correction for within-group evaluation and one-way analysis of variance along with Toki post-hoc test for between-group evaluation ( a<%5). The results showed that morning and evening aerobic training significantly decreased LDL-c and significantly increased HDL-c in the experimental groups compared to the control groups. However, the total levels of cholesterol and triglyceride remained unchanged in these groups. In addition, no significant difference was observed in LDL-c and HDL-c levels between morning and evening training groups when the training was completed. It was also demonstrated that aerobic training during morning and evening could influence the compatibility of cardiovascular risk factors. And finally, no difference between the effect of aerobic exercise during morning and evening was observed on overweight men.

The purpose of this study was to examine the effect of CoQ10 supplement consumption during tapering phase on some of endurance performance indices in middle distance runners. To do this, 18 trained middle distance male runners with an age of 21±1.26 years old, a weight of 65.6±4.7kg and height of 179±2.5 were selected. This study was based on the pre test - post test method with two experimental groups and one control group. Study subjects were prepared for the pre test after 10 weeks training to increase aerobic and anaerobic endurance, lactate threshold, lactate tolerance under 70-95% MHR and 4 sessions training in one week (70-90 min/session). The pre test was then conducted which included rest heart rate (RHR), sub maximal heart rate (SubHR), maximal heart rate(MHR), 1mile test and time to exhaustion (Tex) (pre-taper). After that, the pre test participants were divided into three equal groups including T+Q10 (i.e. 1week tapering with Q10,120 mg/day), T (i.e. 1week tapering with placebo) and C (i.e. continued previous training with placebo). In the tapering period, the volume of training progressively decreased and its intensity increased to 135% of Vo2max while the frequency was constant. At the end of the tapering period (POST taper) all previous tests were measured respectively. To investigate mean differences between PRE and POST-test variables, the dependent student t-test was selected, and for the analysis of mean differences between the groups ANOVA was used. The obtained results showed that there is a significant decrease in RHR and SubHR in the groups of T and T+Q10. The 1mile test record and Tex were significantly improved (P<0.05), whereas there was no difference in MHR (p>0.05). It may be concluded that the COQ10 consumption in the tapering period has no significant effect on variables considered (p>0.05). Similarly, no significant change was experienced in the variables after one week in group C (p>0.05). In conclusion, the obtained results demonstrated that the COQ10 supplementation with one week tapering period has no effect on the performance of variables considered in this study. However, the tapering period could improve the RHR, SubHR, Tex and 1mile test performance with no effect on MHR.

This study aimed to compare the effects of high intensity and high volume training on lactate accumulation, time performance and VO2peak in 10-14 years old distance runners. 20 male endurance runners aged 12.5±2.32 years old and with a height of 154.62±3.27 cm, weight of 34.5±5.12 kg, maximum heart rate of 207.5±3.1 and VO2max of 36.45±3.22 ml /kg/min took part in the experiment. The experiment was undertaken randomly in a crossover form between two modes and two groups of runners (Group A and B), and two intermittent exercise models. The exercise models included: (i) a high intensity and low volume (HT) model (60 seconds exercise with 90% VO2 peak and 60 seconds rest with 30% VO2 peak) within 30 minutes activity and (ii) a low intensity and high volume (VT) model (60 seconds exercise with 65% VO2 peak and 60 seconds rest with 30% VO2 peak) within 60 minutes activity. The experiments were performed during two 6-week periods with a 5-week rest in between. Respiratory Exchange Ratio (RER), Time performance in 1500 meters (T1500m) and Lactate maximum (Lacmax) were measured throughout the exercises. Repeated-measures ANOVA and Bonferroni post hoc tests were used to determine any significant difference between the groups and exercises. The results showed that there was a significant difference in the value of T1500m between pre and post HT and VT models (P<0.05).With regard to the maximum amount of RER and lactate, there was only a significant difference between pre and post HT exercise model (P<0.05). The results revealed that both HT and VT models had a significant difference in VO2peak between pre and post exercise (P<0.05). Overall, the findings of this study showed that the HT exercise model compared to the VT exercise model had higher performance on the RER, Lacmax, T1500m andVO2peak parameters. Where time limitation is an issue for athletes, the HT exercise model may therefore be a good substitution for long and boring training models.

Introduiction: This study aimed to investigate the protective effects of 12-week voluntary exercise using a running wheel on the striatum dopaminergic neurons against 6-hydroxydopamine lesions in rats. Materials and method: Twenty five rats were divided into three groups including healthy, parkinson and training-parkinson. The training groups were housed in individual cages geared with running wheels. To induce parkinson, 250 microlitre of 6-hydroxydopamine (6-OHDA) dissolved in saline was administered intracerebrovenricular (ICV) by a stereotaxic apparatus. Tyrosine hydroxylase and dopamine levels in the striatum were measured by ELISA. The obtained data was analyzed using one-way analysis of variance (ANOVA) and least significant difference (LSD) post-hoc test. Results: The mean running distance of subjects was 5384 meter per day. In this study, dopamine levels between the exercise and parkinson control groups had significant differences. In other words, a decrease in the dopamine level was prevented in the training group (P=0.001). Dopamine levels in the exercise group remained almost the same level as the healthy group (P=0.129). However, the tyrosine hydroxylase level did not change in the training and control groups. Conclusion: Pre-treatment with the voluntary exercise causes an increase in the strength and life-span of dopaminergic neurons striatum against oxidative damage caused by 6-OHDA toxicity, and has a protective role against Parkinson’s disease.

Muscle-derived neurotrophins are thought to contribute to the adaptation of skeletal muscle to exercise. The NT-4.5 protein is one of the family members of neurotrophins that remains rather unknown compared to other members. The aim of this present study was to determine the effect of one session of resistance exercise on the levels of NT-4.5 protein in Soleus and Flexor HallucisLongus muscles of male wistar rats. 24 wistar rats (230±20g) were randomly assigned into two groups including (i) control group (N=8) and (ii) exercise group (N=16). In the exercise session, animals in 3 sets and 5 times climbed up a ladder while carrying 30% of their body weight. Animals of the exercise group were sacrificed 24 and 48 hours after exercise and their Soleus and Flexor HallucisLongus muscles were removed. The levels of NT-4.5 protein were measured using the Elisa kits. One-way ANOVA and independent T-test were used to analyze the obtained data. The results showed significant increases in NT-4.5 protein levels in the Soleus muscle at 24 and 48 h after resistance exercise whereas one session training did not significantly affect the levels of NT-4.5 protein in the FHL muscle. Since one session of resistance exercise resulted in changes in the levels of NT-4.5 protein, this exercise model may be considered as an appropriate model to stimulate the response of muscle-derived neurotrophin, especially in slow muscles.

To date, most studies have focused on continuous aerobic training and there is not comprehensive information about the influence of discontinuous aerobic training on cardiovascular risk biomarkers. Taking this into consideration, the purpose of the present study is to investigate the influence of an 8-week discontinuous aerobic training program (3×10 min) on cardiovascular risk biomarkers in inactive obese women. 20 inactive obese women with BMI³30Kg/m2 volunteered to take part in this study. They were randomly divided into two equal groups of 10 called the discontinuous aerobic group and control group. The training was programmed for 8 weeks, 3 sessions in each week and three 10-min exercises in each session with a 5-min break between each exercise and 60 to 65 percent of maximum heart rate. The blood sampling ELISA method was used to measure the variables required from the discontinuous and control groups before and after the training program at overnight fast. The data were analyzed using paired t-test and independent t-test in the significance level of (P<0.05). The results revealed that discontinuous training program significantly decrease the level of HCY, FIB, TNFa, IL-6, and CRP in obese women (P<0.05). Also the results of independent t-test indicated that there is a significant difference between discontinuous aerobic training and control groups regarding the considered variables (P<0.05).The current study suggested that the discontinuous aerobic training can lead to the plasma reduction on cardiovascular risk factors in obese women. This reduction can be influential in preventing, controlling, and decreasing cardiovascular biomarkers.

The purpose of this study was to determine the effect of six-week high intensity interval training (HIIT) on fibrinolytic factors (t-PA, PAI-1 & t-PA/PAI-1) in sedentary young men. Eighteen inactive young men voluntarily took part in this study and were randomly divided into two groups including the experiment group (n: 9, age: 24.33±1.41, height: 176.22±4.91 and weight: 72.27±6.59) and control group (n: 9, age: 23.27±2.01, height: 180.22±6.88 and weight: 76.27±7.33). The experiment group performed three weekly HIIT sessions over 6 weeks. Each session consisted of either four to six repeats of maximal sprint running within a 20m area with 20–30s recovery. The control group was instructed to continue their normal behavior. Fasting blood samples were collected 24 hours before and 48 hours after the exercise protocol. The obtained data were analyzed using independent t-test. The results showed that the resting levels of PAI-1 were significantly reduced in the experiment group compared to the control group (P=0.012). However, there was no significant difference between the t-PA and complex t-PA/PAI-1 levels after exercise intervention compared to the control group (P=0.257 & P=0.127). Also, the present study showed a significant increase in VO2max and plasma volume. In contrast, it revealed a significant body fat decrease in the participants of the experimental group compared to the control group. Overall, it appears that a six-week HIIT not only effectively reduces body fat but also increases aerobic fitness, and, more importantly, leads to improvement of the fibrinolysis process in sedentary young men.

Obesity is known to increase the risk for cardiovascular diseases. Serum levels of cellular adhesion molecules are reported to be indices of arthrosclerosis. So each intervention that has benefit effects on them is very important for general health. The purpose of this study was to determine the effect of high interval intensity training programs on ICAM-1. 18 sedentary obese males with MEAN±SD age, %BF, weight and BMI: Exp 1 (20.55±1.34 y, 26.84±4.07, 93.05±9.02 kg and 31.20±3.33 Kg/m2) were randomly divided to two groups, the experimental and control groups. participated in 16 weeks of moderate to high intensity interval training (8-10 × 4 minutes sets of running at 60-90% of Reserve Heart Rate and 2 minutes rest interval at 40-50% of Reserve Heart Rate) three days per week. The blood sampling was performed after 18 fasting hours in baseline and 48 h after final training sessions with the same conditions. Resulting data were analyzed by independent-sample t test, person correlation coefficient and pair t-tests (p=0.05). Data analysis showed that ICAM-1 decreased in experimental group but only was significant in EXP 2 (p= 0.015).There was no relationship between baseline of sICAM-1 with physical variable and lipid profile (P >0.05). There was positive correlation between %BF and BFM changes and ICAM-1 changes (P <0.05).The TC, LDL-C and RF levels significantly decreased.