Sport Physiology
Year:2011 | Volume:3 | Issue:10|Papers Count:10

In the present study levels of physical activity was evaluated via daily energy expenditure in 8-16 years old boys of the North West schools of Iran. 2787 students (8-16 years) of the North West schools of Iran participated in this study. Subjects' age (year), weight (kg), height (cm), fat percent, BMI (kg.m-2) and daily energy expenditure (DEE, kJ.kg body weight-1.day-1) were measured. The test-retest method was used to evaluate the QAPACE questionnaire reliability. Paired t-test, intra-class correlation (ICC) and Pearson correlations coefficient were used to evaluate and assess of the test retest reliability of the QAPACE questionnaire. Values of lCC for fat% were 0.99, 0/99 and, 0.99, for DEE were 0.98, 0.98 and 0.99 and for BMI were 1.00, 1.00 and 1.00 for three age categories of 8-10, 11-13, and 14-16; respectively. In addition, our results indicated that subjects in age category of 8-10 had higher DEE and subsequently higher physical activity levels than age categories of 11-13 and 13-16. Moreover, 13-16 years old boys had higher DEE and subsequently higher physical activity levels than age categories of 11-13. In the age categories of 8-10, 11-13 and 14-16 years, daily energy expenditure were 131, 120.4 and 121.85 (kJ.kg body weight-1 day-1); respectively, which were lower than average levels of international norm (At the level of 50%, they were 138, 124, and 136 kJ.kg body weight-1.day-1 respectively). The results of present study showed that the students at three age categories have lower daily energy expenditure compared to the international standard norm for daily energy expenditure, and that the QAPACE questionnaire is reliable for evaluating physical activity levels by using DEE at 8-16 years old boys of the north west schools of Iran.

Available studies show that the moderate intensity training which reduces the parameters of oxidative stress in the hippocampus, resulting increasing the brain-derived neurotrophic factor (BDNF) levels. However, less attention has been paid to examine exercise-induced neuroprotection after administration of lead acetate. In this research, the effects of 8-weeks of exercise training on malondialdehyde (MDA) and BDNF levels in hippocampus of rats exposed to lead acetate were investigated. The Wistar rats were randomly assigned into following four groups: Base, Sham (control), lead acetate (L), and training+lead acetate (Ex-L) groups. The exercise training protocol consisted of running on treadmill at a progressive intensity for 8 weeks and five sessions a week. Ex-L and L groups received 20 mg/kg lead acetate, peritoneally, for 8 weeks (3 days in weeks). Twenty four hours after the last session of training and/or injection, MDA and BDNF levels were measured by TBARS and ELISA methods in rat hippocampus region, respectively. Data were analyzed by using one-way ANOVA and Tukey at P<0.05. Results showed that MDA concentrations in the Ex-L group were significantly lower and in L group were significantly higher than Sham and Base groups. BDNF levels in the Ex-L group were significantly higher than Lead group. These results indicate the beneficial effects of regular exercise training in preventing damage to hippocampal neurons, which contributes to oxidative stress. Furthermore, probably BDNF levels and oxidative status may be involved in the mechanisms of exercise-induced neuroprotection after administration of lead acetate.

Calcitonin gene-related peptide (CGRP) is a 37-aminoacide peptide that is transported in somatofugal direction in peripheral nerve and probably has a role in the muscle protein synthesis. The purpose of the present study was to investigate the effects of Endurance, Resistance and Concurrent training on CGRP content in Sciatic Nerve of Rats. Thirty two male wistar rats were randomly divided into four groups with eight animals in each group including: Control, endurance, resistance and concurrent groups. Endurance training group exercised on treadmill for 12 weeks, 5 times a week, and 60 minutes a day at 30 m/min. Rats in resistance training group were housed in metal cage with 2m high wire-mesh tower, with water bottles set at the top.Concurrent training group performed a combination of both resistance and endurance training. Forty eight hours after the last session of training protocol, rats were anaesthetized and sciatic nerve was removed for CGRP assay using ELISA method. One way ANOVA (p<0.05) was used to analyze data. No significant increase in CGRP level found in all training groups compared to control group. In addition, there were no significant differences among all training groups. The results of this study were in agreement with reported data on the effect of training on axon CGRP. It could be concluded that three training protocols improve axonal transport of CGRP.

The present study attempts to investigate the influence of music tempo on anaerobic performance of male physical education students. For this reason, 45 male physical education students (age, 21.93±1.81 yr; weight, 68.05±11.73 kg; BMI, 22.27±3.08 kg/m2; height, 172.27±16.22 cm) were selected and randomly divided into three groups: a control group and two experimental groups which were divided into a high tempo group (bpm=140) and a low tempo group (bpm=100). The performances of these groups were evaluated at pre- and post-testing. Prior to the experiment the participants were asked to choose one piece of music among the presented music (There were different pieces of music for experimental groups). After 10 minutes warm up, participants performed Wingate test with and without music, during which different indexes of anaerobic performance (peak, mean and drop percent) were measured. Data were analyzed by using one way ANOVA at P<0.05. The results showed that there is no significant difference between 3 groups in their anaerobic power indexes. Although other factors such as peak and mean power were different, the differences were not significantly different. Based on these results, it seems that listening to music prior to performing an anaerobic exercise has no effect on maximal performance.

The purpose of the Present study was to examine the effects of a period of high intensity interval training on selected aerobic and anaerobic performance, and hematological indices. Fifteen trained wrestlers were randomly assigned into two groups (Experimental=8, Control=7). Before and after the training, subjects performed 1) a progressive exercise treadmill test to determine maximal oxygen consumption (VO2max), the velocity associated with V02max (vVO2max), the velocity associated with lactate threshold (vLT) and peak oxygen pulse (VO2/HRpeak), 2) time to exhaustion test with vVO2max(Tmax), 3) RAST protocol to determine peak power output (PPO) and mean power output (MPO).Resting blood samples were collected before and after the training. Both groups followed the same wrestling training program for 4 weeks, additionally, experimental (EXP) group performed a running-based anaerobic sprint test (RAST) as a high-intensity interval training program for 4 weeks, two sessions per week. Differences between pre and post-training values were evaluated by paired t-test. Differences between groups were determined using independent t-test and effect size was calculated for each variable. After the training, VO2max (5.4%), vVO2max (3.1%), vLT (4.1%), VO2/HRpeak (7.7%) and Tmax (32.1%) were increased significantly in EXP group. Following the training, PPO (34.9%) and MPO (29.3%) were increased significantly in EXP group but not in control group. Significant increases were observed in hemoglobin (6.7%), mean corpuscular hemoglobin (4.9%) and mean corpuscular hemoglobin concentration (4.4%) in EXP group (P<0.05). Present findings suggest that a period of high-intensity interval training induces improvements in aerobic and anaerobic performance in short period of time and low volume of training (4 min per session) which were accompanied by hematological changes.

We investigated the effects of an aerobic training program on resistin, adiponectin and insulin resistance index in type 2 diabetic men and also examined relationships between these two adipocytokine with insulin resistance index. Thirty middle-aged men with type 2 diabetes were randomly assigned to either a training (n=15, age, 58.8±6.65 yr, body mass index (BMI), 26.38±3.75 kg/m2) or control group (n=15, age, 53.50±4.50 yr, BMI, 26.31±2.17). The training program consisted of 8 weeks of aerobic exercise at an intensity corresponding to different maximal heart rate (35-75% HRmax), 3 times a week on a treadmill. Blood samples were obtained from all subjects after an overnight fast before and after the training program. Fasting sera kept at -80oC were used to measure serum adiponectin and resistin concentrations by using ELISA technique. Paired ttest, Mann-Whitney U tests and Pearson's correlation coefficient were used to analyze the data. Compared with controls, training increased adiponectin levels by 39% (p<0.001), decreased resistin serum levels by 49% (p<0.001), decreased body mass index (BMI) and bodyweight by 10% and insulin resistance by 48%. In the training group, significant changes in adiponectin serum levels was not correlated with changes in insulin resistance index (r=-0.14), while changes in resistin levels were correlated with changes in insulin resistance index (r=0.60). This study revealed that along with reductions in BMI and body weight, eight weeks of aerobic training induces a marked reduction in resistin and insulin resistance index, and increases in adiponectin in men with type 2 diabetes. Our findings also showed no correlation between changes in adiponectin and insulin resistance index, while there was a positive correlation between changes in resistin and insulin resistance index.

The aim of this study was to investigate the effects of a low impact rhythmic aerobic exercise on C - reactive protein (CRP) in elderly women. Twenty three elderly women (weight, 59.2±11.6 Kg; height, 152.2±5.4 cm; age, 67.3±3.9 years) participated in the study and were divided into two groups including experimental (n=13) and control (n=10) groups. Anthropometric characteristics including height, weight, body mass index (BMI), waist to hip ratio (WHR) were measured and recorded and thereafter a resting blood sample was taken between 8-9 am in a fasting state. Training protocol lasted 8-weeks including 3 sessions per week and each session lasted 40-50 minutes. Each session included warm up (10 minutes), standing aerobic exercise (30 minutes at 40-75% maximum heart rate) and cool-down (10 minutes). Forty eight hours after last training session anthropometric characteristics and a resting blood sample were taken similar to pre-training condition. Within and between groups differences were detected by using paired t-test and independents t-test, respectively. Data analysis revealed that low impact rhythmic aerobic exercise decreased CRP significantly (p<0.01) in elderly women whereas, no significant decreases were observed in control group (p>0.05). In addition a significant (p<0.01) difference between experimental and control groups was found for CRP. Finally, findings of the present study show that low impact rhythmic aerobic exercise not only has a significant and positive effect on CRP elderly women but also leads to improvements in cardiovascular factors.

Brain-derived neurotrophic factor (BDNF) is a 119-amino-acid dimeric protein, and is structurally related to nerve growth factor (NGF). Purpose of the present study was to evaluate the effects of 8 weeks of endurance training at different durations on plasma BDNF in male rats. Forty adult Wistar male rats (6-8 weeks old, 189±10 g) were recriuted in this study.Rats were divided into control, Sham, and two training groups. Training groups performed running on treadmill at 20 m/min (0% grade), 5 days/week for 8 weeks. Duration of exercise was 30 min/session in one group and 60 min/session in the other group. Rats were sacrificed 72 h after the last session of training for measurement of plasma BDNF levels. Data were analyzed using one-way ANOVA and LSD post-hoc test. Plasma BDNF concentrations were significantly (P<0.05) higher in both training groups than control group. Levels of BDNF rose in both training groups and there was no significant difference between two groups. It could be concluded that exercise training increases BDNF irrespective of exercise duration.

Purpose of the present study was to investigate the effects of aerobic training and caloric restriction on cellular and vascular adhesion molecules in obese women. Forty sedentary obese women (Mean±SD, age, 20.4±1.26 years; BF%, 26.6±3.95 and BMI, 30.6±2.81 kg/m2) were selected and randomly allocated to EXPt1 (Aerobic training), EXP2 (Caloric restriction), EXP3 (concurrent intervention) and control groups. Eight weeks of training in EXP1 included running on treadmill for 50-60 min, 5 day/week, while, EXP2 used a caloric restriction diet with equal energy to EXP1. EXP3 a diet and aerobic training with energy restriction equal to EXP1 Fasting serum samples were analyzed for VCAM-1 and ICAM-1 levels before training and 48 h after training. Data Analysis showed that weight, BMI and BF% decreased significantly in the experimental groups, with the changes being higher in EXP2 by 4.6%, 4.6% and 9.1%, respectively (p<0.05). Results revealed decreases of ICAM-1 in EXP1, EXP2 and EXP3 equal to 9.3%, 19.7% and 23.1%. The decrease of Icam-1 significant in EXP2 (aerobic training) (p=0.05). The levels of VCAM-1 in experimental groups were decreased, but these decreases were not statistically significant (p>0.05). A low level of correlation was seen between changes in adhesion molecules levels with BF% and weight (p>0.05).

The purpose of present study was to compare serum metalloproteinases (MMPs) in response to one bout of sub-maximal exercise in active and nonactive men. Eight active men (Mean±SD, VO2max, 43±1.6 ml/kg/min) and eight non-active men (Mean±SD, VO2max, 31±1.4 ml/kg/min) completed a sub-maximal exercise at 50% of VO2max. Blood samples were collected before, immediately after and 2 h post-exercise. The Data were analyzed using repeated-measures and two ways ANOV A. Sub-maximal exercise did not significantly change serum MMP-2 in active (p=0.119) and non-active (p=0.175) group but increased serum MMP-9 immediately (p=0.001) and 2 h (p=0.000) after exercise in active and immediately (p=0.009) and 2 h (p=0.003) after exercise in non-active group. However, results showed no significant difference between serum MMP-2 and MMP-9 in active and nonactive group at any time points (p=0.423). In conclusion, it appears that the responses of angiogenic metalloproteinases to one bout of sub-maximal exercise are similar in active and non-active men.