فصلنامه فیزیولوژی ورزشی
پیاپی 44 (زمستان 1398)

The purpose of this study was to compare the effect of 8weeks aerobic activity (closed skill) in a stable and predictable environment and soccer training (open skill) unpredictable and variable environment on the levels of brain-derived neurotrophic factor in recovered addicts. The research design was pre-test and post-test with control group. 45 males who addicted were the main subject matter of the methamphetamine, were randomly assigned to aerobic training, soccer practice and control groups.values brain-derived neurotrophic factor ​​was measured before and after the end of the intervention. One-way covariance analysis was used for inter-group comparisons and the data were analyzed using SPPS version 24. The results of this study showed that eight weeks of aerobic training and soccer practice significantly increased the serum levels of brain-derived neurotrophic factor in recovered addicts compared to the control group (P <0.05). Also, there was a significant difference between the two groups of football practice and aerobic training by controlling the pre-test values between the post-test values for the benefit soccer training group (P <0.05). In general, according to the results of this study, aerobic activity and soccer training have been shown to increase levels of brain-derived neurotrophic factor in people with addiction to stimulants, and these exercises training, especially soccer training can be utilized to improve the disrupted levels of brain-derived neurotrophic factor in recovered addicts.

The present study investigated the effect of combined post-activation potentiation (PAP) and transcranial random noise stimulation (tRNS) on maximal muscle activity in maximum voluntary isometric contraction test (MVIC) and integrated electromyography (IEMG) when knee extension was kept on the leg extension machine. 10 athlete students from wrestling, track and field and volleyball with mean age of 29/1 years performed one of four protocols that included usual warm-up plus sham tRNS (control group), usual warm-up plus tRNS, usual warm-up plus performing a set of right leg extension (80% of 1 repetition maximal) on the leg extension machine and usual warm-up plus tRNS plus a set of right leg extension in four separate sessions which occurred 24 hours after each other. The brain waves activity levels and electromyogram activity of vastus lateralis, rectus femoris and vastus medialis muscles were recorded simultaneously by using electroencephalography and electromyography respectively when the subjects performed were performing the test. The results showed a significant increase in the absolute power of all three brain waves in the Cz channel for every three conditions of the post-test compared to the pre-test during both MVIC (P=0.001) and keeping leg extension tests on leg extension machine(P=0.001). The amounts of maximum muscle activity for MVIC test and muscle IEMG values during keeping leg extension on the leg extension machine showed a significant increase in every three post-test conditions compared to the pre-test for all muscles (P=0.001). The duration of keeping leg extension on the leg extension machine was significantly increased for every three post-test conditions compared to the pre-test (P=0.001). It seems applying of tRNS and PAP, and also combined use of them after warm up can increase brain activity, maximum muscle activity, integrated electromyography and the duration of keeping leg extension in both tests compering to just warm up. Ultimatly, combined use of tRNS and PAP has an impressive effect compared to applying them separately.

The purpose of this study was effect of eight weeks of resistance training with citrulline-malate supplementation on blood pressure, serum nitric oxide and vascular endothelial growth factor in in rest rate and response to physical activity in postmenopausal women with prehypertension. 42 postmenopausal women (Age: 53.17 ± 1.82-year, height: 158.91 ± 1.86 centimeter, BMI: 28.79 ± 1.71 kg/m2) with prehypertension (with an average systolic blood pressure of 120 to 139 mmHg) were randomly assigned into six groups: exercise + supplements, exercise + placebo, exercise, untrained, supplemented, supplemented, and placebo. Resistance training includes 7 moves and was performed three times, every move three sets of 12-10 reps for week with intensity %45-%55 of 1RM for 8 weeks. Supplementation included 8 grams of Citrulline-Malate one hour before exercise. Measurements in 4 times before and after exercise, blood pressure, NO and VEGF were measured using a barometer and kit. ANOVA test, Tukey post-hoc test and dependent t-test were used for analyzing the data at a significantly level 0.05. Two-way ANOVA and Tukey post hoc tests were used for the significant level (P < 0.05). The results showed that consumption of citrulline-malate was effective in decreasing systolic, diastolic blood pressure and NO in response to endurance activity. However, eight weeks of training had no significantly effect on the reduction of systolic, diastolic and increased NO and VEGF in response to endurance activity. Also, resistance training with citrulline-malate as effective in decreasing systolic, diastolic blood pressure, and increased NO and VEGF in response to endurance activity. It seems that the effect of exercise+ supplements on the reduction of systolic and diastolic blood pressure in response to submaximal endurance activity, these favorable effects were associated with an increase in NO and VEGF levels.

Considering the apelin effects on glucose metabolism, insulin, and its changes in hypoxia condition conditions, this study aimed to investigate the effect endurance training in normobaric hypoxia on apelin and insulin resistance in overweight men. Twenty healthy overweight men (Mean±SD; Age, 23.1±6.7; BMI, 28.2±1.9) that voluntarily participated in this study were randomly divided in to two hypoxia and normoxia groups. The eight-week training of the hypoxia group was performed at a simulated altitude of 2,700 meters in a hypoxia tent with an intensity of 60% of maximum oxygen consumption and normoxia group training was performed in normal conditions. Blood sampling was done in two groups, before and after 48 hours after the last training session, and used for measuring apelin and insulin and glucose levels. Mixed ANOVA test was used for comparing all variable at a significant level of P≤0.05. The results of comparing all variables changes in both training conditions showed that 8 weeks of training in hypoxic conditions did not affect body composition and VOmax indices compared to exercise in normal conditions (P>0.05), but significantly increased Apelin and significantly decreased insulin resistance and Insulin compared with the normoxia group (P<0.05). This study showed for the first time that eight weeks of training in normobaric hypoxia conditions caused an increase in the apelin serum level in overweight men, and training in hypoxic conditions compared to exercise in normal conditions, cause further decrease of insulin resistance.

Weakness, intolerance of exercise and eventually muscle atrophy are important features of patients with heart failure. Therefore, the purpose of this study was to investigate the effect of 8 weeks of high intensity interval training on ubiquitin-proteasome system in fast twitch muscle of post myocardial infarction (MI) rats.

Myocardial infarction was induced by left artery descending ligation for 30 min. 32 male Wistar rats were randomly divided into 4 groups (n = 8): MI control (MI-CTL), high-intensity interval MI (MI-HIIT), high-intensity interval (HIIT) and Sham- operated. Exercise training was undergoing 40 min, 3 sessions per week for 8-weeks (85-90% VO2max). 24 hours after the last training session, the rats were anesthetized and their extensor digitorum longus (EDL) tissue removed. RT-PCR method was used to measuregene expression (NOX2, TNF-a, NF-KB, P38 MAPK, Murf-1) was used. Data analysis were performed using a one-way ANOVA and Tukey follow up tests, considering as significance level (P < 0.05).

8-week HIIT significantly decreased NOX2, TNF-a in MI-HIIT compared with MI-CTL and Sham (P=0.03). These reductions wereparalleled a significant decrease in activity NF-KB, P38, Murf-1 in MI-HIIT compared with MI-CTL and Sham (P<0.05). Also, NOX2 change in HIIT group was significantly higher than MI-CTL and Sham (P<0.05). According to the results of HIIT probably as an effective treatment, it reduces muscle atrophy in fast muscle contraction of heart patients.

The purpose of the current study was to investigate the effect of coingestion of caffeine and L-carnitine supplements on substrate selection during exercise and its probable effect on endurance performances in elite male karate. Twelve elite athletes performed a progressive standard test following placebo (250 mg Lactose), caffeine (5 mg/kg), l-carnitine (3 g), and caffeine and l-carnitine (5 mg/kg, 3 g) consumption in four sessions separated by one-week interval. Respiratory gases and blood samples were collected before and after exercise. Cross over point (COP), as a point that metabolic substrate changes from fat to carbohydrates, and Fatmax, as a point at which fat has the highest contribution to energy supply, were determined, workload and oxygen consumption corresponding to them were extracted, and compared among trials by repeated measures analysis of variance. Following consumption of caffeine alone and in combined with L-carnitine, the changes in plasma free fatty acid (FFA) during exercise, workload and oxygen consumption corresponding to COP and Fatmax points were significantly higher compared to the control trial (all P < 0.05). The values of these variables in combined trial were significantly higher than those found in the caffeine trial (all P < 0.05). L-carnitine consumption did not induce significant change in these variables compared to the control trial. In sum, Caffeine consumption improves endurance performance through changing substrate selection during exercise toward fat and this effect could be exacerbated by simultaneous consumption of L-carnitine.