جستجوی مقالات مرتبط با کلیدواژه « Exercise Intensity » در نشریات گروه « تربیت بدنی »

Thrombotic events are common during old age and high intensity interval exercise (HIIE) is prescribed on the health of elderly individuals. Nevertheless, effects of high intensity interval exercise (HIIE) on hemostasis in elderly individuals have not been investigated. Therefore, the present study aimed to investigate the response of hemostatic factors to different HIIE protocols and moderate continuous exercise in elderly male wistar rats.

Twenty-four elderly male wistar rats were divided into four groups. Rats in the high-intensity interval exercise with low-volume (HIIEL) group performed 14 bouts of 20s of activity with 10-second rests at an intensity of 110% of maximum tolerable load (MSL). Rats in the high intensity high-volume interval group (HIIEH) performed five bouts of four min swimming at 80% of MSL followed by three min rest and finally in the continuous group (CTN) the  rats swam for 35 min at 60% of MSL. The control group remained immersed in water for 35 minutes without activities. Blood samples were taken immediately after exercise for measuring lactate and hemostatic factors. The statistical analysis of the data was performed using one-way analysis of variance at a significance level of p<0.05.

Lactate concentration was increased following HIIEL in comparison to other groups. In addition, in the HIIEL and HIIEH groups, sports activity led to a significant increase in the Von Willebrand factor.  Although, the VIII factor and fibrinogen increased and decreased in both CTN and HIIEL groups, respectively and decreased and increased in HIIEH group, the changes were not significant. Also, significant changes in dimer levels, relative activated thromboplastin time and prothrombin time after swimming were not seen in any group.

Based on higher increases in von Willebrand factor following intense interval exercise (compared to continuous exercise) it is concluded that moderate continuous exercise might be safer than HIIE during old age.

 Physical activity is one of the most effective ways to improve cardiovascular function. The present study was performed to evaluate cardiovascular responses following high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in inactive obese men.

 In the present semi-experimental study, eight inactive obese men (age: 22.5 2 2.5 years, body mass index: 31.5 ± 1.5 kg / m2) using a randomized crossover design, participated in three HIIE, MICE and control interventions.  Blood samples were taken before, immediately and one hour after exercise to measure nitric oxide (NO) concentration. Also, heart rate and blood pressure were measured before, immediately and every 15 minutes for one hour after exercises.  

  No significant changes in hemodynamic factors and NO were observed in the control group. However, after HIIE and MICE protocols, a significant decrease (p <0.05) in systolic blood pressure (SBP) was observed compared to baseline conditions, which this phenomenon has persisted for a long time following HIIE. Heart rate and NO increased significantly after both protocols (p <0.05), with the increase in NO following HIIE persisting for longer.

It seems that training intensity can be an influential factor in the development of PEH. Also, due to the longer increase in NO caused by HIIE compared to MICE, it can be considered that longer PEH after HIIE is probably related to the mechanism of NO-induced vasodilation.

The aim of this study was to investigate the effect of two types of resistance exercises of high volume (HV) and high intensity (HI) on α2bβ3 receptor, and markers of platelet activation and function. Among the volunteers, 10 individuals familiar with resistance training (6 women and 4 men; age, 28±5 years; weight, 67.1± 10.7 kg; height, 168±9 cm) performed two resistance exercises of HV and HI including 5 exercises. In HV protocol subjects performed 4 sets of 10-12 repetitions at 70% of 1RM with 1 min rest between sets and exercises and in HI protocol subjects performed 4 sets of 3-5 repetitions at 90% of 1RM with 3 min rest between sets and exercises. Blood samples were taken before, immediately after exercise and after 30 min recovery for measuring PDW, PLT, MPV, PAC1, CD41a, CD42b and CD62p. Data were analyzed using two-way repeated measures of ANOVA. Significant increases in blood lactate levels, PLT following resistance exercise were higher in response to HI protocol were higher than HV protocol. The results showed a significant decrease in CD41a (α2bβ3 receptor) and CD42b, and a significant increase in PAC1 and CD62p (p<0.05). Changes in CD41a, CD62p, and PAC1 were higher following HI than the HV protocol (p<0.05). Based on the findings of present study it could be concluded that α2bβ3 receptor, markers of platelet activation and function change in response to resistance exercise and that intensity of resistance exercise is more effective than volume of exercise.

Environment conditions such as altitude affected on urinary system, however the effect of exercise intensity in hypoxia condition on urinary system is not well known. Thus the aim of present study was to examine the urinary excretion of sodium, potassium and urea in response to different intensities of aerobic exercise in hypoxia and normoxia conditions in young soccer players. 

 Ten young soccer players (age: 18.2 ± 0.5; Height 174.2 ± 4.1 cm; Weight: 64.4 ± 3.6 kg; BMI: 21.2 ± 2.1 kg/m2 mean ± SD) were participated in this study as the subject. They performed 30 min aerobic training with 55, 70 and 85% of their maximum heart rate on treadmill in normoxia condition. After 48h, the same exercises were performed in hypoxia (2500 meters higher than the sea level) condition. Before and 20 min after the each exercise, urinary sample was collected to evaluate urinary excretion of sodium, potassium and urea. 

 The results indicated that sodium excretion were increased as well as exercise intensity increased in hypoxia and normoxia conditions (p < 0.05). Results demonstrated that after high intensity exercise in hypoxia and normoxia conditions and after moderate intensity exercise in hypoxia condition, potassium excretion were decreased significantly (p < 0.05). For urea excretion, no significant differences were observed after different exercise intensities in hypoxia or normoxia condition. 

 Generally, it seems that sodium excretion increased and potassium excretion decreased as well as exercise intensity increased in hypoxia and normoxia conditions and this predominate in hypoxia condition. Therefore, this is very important to electrolyte balance maintaining during high intensity exercise in hypoxia condition.

The aim of this study was investigation of the effect of exercise intensity on accuracy of arterial CO2 pressure estimation from end tidal CO2 pressure.

Ten subjects were selected as samples. At first, the maximum oxygen consumption (VO2max) of each subject was obtained by performing progressive exercise protocol. Then, each subject performed three protocols with intensities of 30%, 50% and 70% of his own VO2max and duration of each exercise was 12-minute. Blood samples were taken during the rest, exercise and recovery periods, and data on respiratory gases were collected.

Correlation coefficient between PaCO2 and PaCO2pre and P value in exercise with intensities of 30%, 50% and 70% of VO2max were r = 0.807, P=0.001; r=0.822, P= 0.001 and r = 0.552, P= 0.003 respectively. The percentage of estimation error was higher in the intensity of 70% of VO2max than intensities of 30% and 50% of VO2max.

Based on the findings of this study, it seems that the accuracy of prediction of arterial CO2 pressure from end tidal CO2 pressure is lower in high intensities exercise than low intensities exercise.

In the present study, decision making behaviors of elite soccer players at three exercise intensities (rest, 40% maximum and 80% maximum) and three motivational situations (low, moderate and high) were assessed. 14 elite male soccer players with minimum 8 years of playing experience participated in this study (mean age 23/07). Data was analyzed using factorial analysis of variances and repeated measures at significance level of P<0/05. When arousal was medium or high, increasing the exercise intensity was due to decline in accuracy of decision making (P=0/045, P=0/001). But when the arousal was low, there was no difference in accuracy of decision making under three different exercise intensity (P=0/116). Hence, decision making behavior in elite players is affected by interaction of player and environmental constraints during try for reaching specific functional goal.

Introduction and Myocardial infarction (MI) is the most common type of heart disease. According to recent studies, mitochondrial dysfunction has been accepted in the development of heart failure. Exercise training plays a protective role against cardiovascular disease. However, the role of proteins involved in mitochondrial dynamics is not understood in response to exercise training. Therefore, the aim of the present study was to investigate the effects of the intensity of interval training on mitochondrial dynamic proteins in the heart of male rats with myocardial infarction. The present study was performed with experimental posttest design method with control group in 16 week wistar rats. In this study, after MI with ligation of the left anterior descending coronary artery (LAD) and ensuring the creation of MI by echocardiography, rats were subjected to HIIT, MIIT and (LIIT training, Sham (MI-SED) and control (C). Six weeks after exercise, the levels of MFN2, DRP1 and PGC-1α proteins were measured by western blot . data analysis showed that proteins level of MFN2 and PGC-1α decreased significantly in MI-SED group compared to healthy control and DRP1 protein levels increased significantly (P≤0.05). Also, MFN2 and PGC-1α proteins increased in MIIT compared with MI-SED and DRP1 protein levels decreased as well (P≤0.05).
Discussion and Moderate-intensity interval training (MIIT) leads to improved mitochondrial fusion and fusion proteins in rats with myocardial infarction. While high and low intensity interval training, despite increasing MFN2 and PGC-1α and reducing DRP1, failed to improve fusion and mitochondrial fission

Quantifying the relationship between volume and intensity as key components of training is a precise manner that is complicated for most coaches. The aim of this study was to quantify the inverse relationships between training volume and intensity during exhaustive treadmill running among active young men.

32 active young men aged 21 years selected as subjects and completed four exhaustive treadmill running in the four separate phases at 70%, 80%, 90%, and 100% VO2 with at least 72 hours rest intervals. The inverse relationship between regression.

The results showed that the inverse relationship between volume and intensity of exhaustive treadmill running obeys a second-order polynomial regression where the volume of exercise (VE min) is a function of exercise intensity (EI beat/min) (VE min= 0.0225(HR beat/min) 2 – 9.4672 (HR beat/min) +997.91).

It can be concluded that the inverse relationship between volume and intensity of exhaustive treadmill running is non-linear and the fitted equation can be used to predict the volume of exercise based on the exercise intensity among active young men.

Normal liver function is of crucial importance for metabolism and might be affected by exercise training. Accordingly, the aim of this study was to investigate the effects of 8 weeks of resistance training with various intensities on liver function test results in obese males. According to the inclusion criteria of the study, 32 obese males were selected and randomly assigned to 4 groups (each group 8 subjects): control, resistance training with low intensity (30% 1-RM), resistance training with moderate intensity (50% 1-RM) and resistance training with high intensity (70% 1-RM). Three groups carried out the resistance training with different intensities 3 times a week. Blood samples were measured in the pretest, mid-test and posttest (after 12 hours of overnight fasting). The collected data were analyzed by variance analysis test with repeated measures. Body fat percent, ALT, GGT and AST significantly reduced in experimental groups compared with the control group (P

The aim of this study was to examine impact of different intensities of exercise fatigue on increasing and decreasing intra trial stimulus speed on coincidence-anticipation timing. Subjects were 15 volunteer students (20.33±0.97) years of Allameh Tabataba’i University. After sampling and choose proper software (coincidence-anticipation timing software) anticipation all subjects performed 1 block consist of 10 trial with intra trial variation under three fatigue conditions: rest, moderate-intensity and high-intensity exercise on treadmill until the participants reached a steady state of 50% and 80% of heart rate reserve (HRR), respectively. Data was analyzed with Kalmogorov- Smiranov Test normality and homogeneity of variance tests Levine test, repeated measure (ANOVA) and Bonferroni post hoc test frequently in significant level of (0.05). Results showed in increasing rate moderate intensity exercise-related fatigue (50%), variable error was not significant (P>0.05), but absolute error was significant (P0.05), but in high-intensity exercise related fatigue (80%) variable error and absolute error was significant(P

In this study، we established the Persian version of Talk test and evaluated its psychometrics features for determination of aerobic threshold in healthy young females. Three groups of 19 healthy female students (with low، mid، and high aerobic capacity) were selected by stratified purposeful sampling. Giving informed consent، they took part in 2 sessions of Exhausting Graded Exercise Test (EGXT) which were apart by 1 week. TT and gas analysis were administered respectively in first and second sessions of EGXT. Ventilatory estimations of TT were evaluated by results of EGXT. Using SPSS software، data were analyzed by one-way ANOVA. VO2max of 3 groups were significantly different (F (2، 54) ≥32. 44 and P≤0. 01). Nevertheless، in anaerobic threshold، mean (±SD) of HR، Borg Scale، and TT were approximately the same and respectively equaled 177 (±10) pulses، 15 (±2) degree and 24 (±2) words. In anaerobic phase، they were remained the same and respectively equaled 193 (±7) pulses، 18 (±1) degree، and 22 (±2) words. Parallel to previous studies، this study showed that there is a negative linear correlation between Talk tests with intensity of training. Ability to recitation 24 words and more in 30 seconds show aerobic zone and recitation of 22 words and less in 30 seconds show anaerobic zone.

Counting talk test (CTT) is a simple test based on ventilation function which is used to estimate the anaerobic threshold. In this study, it is established the persian version of CTT and evaluated its psychometrics features for determination of anaerobic threshold in healthy young females. Three groups of healthy female students (with low, mid, and high aerobic capacity, n=19) were selected by stratified purposeful sampling. Giving informed consent, they took part in 2 sessions of exhausting graded exercise test (EGXT) which were apart by 1 week. CTT and gas analysis were administered respectively in first and second sessions of EGXT. Ventilatory estimations of CTT were evaluated by results of EGXT. Using SPSS software, data were analyzed using by one-way ANOVA. VO2max of 3 groups were significantly different (F(2, 54)≥32.44 and P≤0.01). Nevertheless, in anaerobic threshold, mean (±SD) of heart rate (HR), Borg scale, and CTT were approximately the same and respectively equaled 177(±10) beat/min, 15(±2) degree and 5(±1) numbers. In anaerobic phase, they were remained the same and respectively equaled 193(±7) beat/min, 18(±1) degree, and 3(±1) numbers. The results showed that CTT can be considered as good as heart rate test and sometimes can be better than Borg scale in determining anaerobic threshold and anaerobic zone. There was a negative linear correlation between CTT and intensity of training. For healthy young females, a counting of 5 indicates working in anaerobic threshold and a counting of 3 means working in anaerobic zone. The use of CTT for determination of anaerobic threshold was confirmed by our findings.

The purpose of present study was to compare fat oxidation rate during and after three different exercise intensities. Eight non-athletes male students (aged, 19.7±1.8 yr; height, 174.3±5.1 cm; weight, 64.5±7 kg; VO2max, 40.1±4.4 ml/kg/min) were in this study and exercised at 55, 65, and 75% VO2max on treadmill at three separate days which elapsed by at least one week. Experimental protocol consisted of a 15 min pre-exercise resting, 60 min exercise, and 2-h recovery periods. Fat oxidation was calculated by using an indirect energy measurement method (Indirect calorimetric) was used throughout the experimental protocol] to measure fat oxidation rate. The results of present study showed that absolute fat oxidation rates during and after 75% VO2max and also total absolute fat oxidation rates were significantly higher than other intensities (P≤ 0.05). Relative fat oxidation rate during 55% VO2max was significantly higher than other intensities (P≤ 0.05), but relative fat oxidation rate and total relative fat oxidation rate were not significantly different after three exercise intensities. Absolute CHO oxidation during the three intensities and total absolute CHO oxidation increased with intensity; however, there was no significant difference in this. But, there was a significant difference in relative CHO oxidation during exercise at 55 and 75 % VO2 max (P≤ 0.05). In post exercise recovery period, absolute and relative CHO oxidation decreased with intensity (P≤ 0.05). Energy expenditure during 75% VO2max and total Energy expenditure were significantly higher than other intensities (P≤ 0.05). It was concluded that exercise with 75% VO2 max can be beneficial to reduce and maintenance of the weight.

The purpose of this study was to determine the effect of two different intensities of exercise on hematopoietic stem cells and relationship with some of cardiovascular risk factors in women.

Fourteen female students from a group volunteers (group 1: mean age 22 ±2 years, BMI 20.81±1.91 kg.m2, n = 7. group 2: mean age 21 ±2 years, BMI 20.38 ± 1.66 kg/m2, n = 7) were randomly selected via questionnaire and each group ran 30 minutes at their (60-75% of Vo2max) on treadmill. Blood samples were taken from all subjects for measurement of hematopoietic stem cells CD34+ and same Isotype control ratio LDL/HDL and Ch/HDL and triglyceride before and 10 minutes after the test. The related t-test (paired) were used for comparisons within a group. To compare variables between the groups were used multivariate analysis of variance test (MANOVA). For determining the relationship between variables Pearson correlation coefficient were used. Statistical significance was accepted as P<0.05.

Results of this study showed that both intensities of exercise increased significantly the number of CD34+ cells, this effect was higher in intensity of 75% VO2max, but was not statistically significant. No significant correlation between CD34+ and ratio LDL/HDL and Ch/HDL and triglyceride was observed.

according to the findings the present study can be expressed that physical activity with intensity 60% and 75% VO2max can increase re-enthotelialisation due to mobilization of CD34+ cells.