جستجوی مقالات مرتبط با کلیدواژه "skeletal muscle" در نشریات گروه "تربیت بدنی"

Physiological and behavioral processes of almost all organisms depend on the time of day. In mammals, light enters these processes in the suprachiasmatic nucleus of the hypothalamus, which forms the body's central clock, and synchronizes the body's functions with the 24-hour cycle of light and darkness. he does. In addition to perceptual and cognitive aspects of performance, circadian rhythms affect many aspects related to physiological performance such as muscle strength and flexibility. There is also a strong relationship between physical performance and (circadian) changes in body temperature, with optimal physical performance coinciding with peak body temperature in the early evening. The circadian clock, which is responsible for the circadian rhythm, exists in almost every cell, and its disruption leads to many diseases such as type 2 diabetes and metabolic syndrome. The findings show that skeletal muscle homeostasis may be disrupted not only due to lack of exercise and low dietary protein intake, but also due to disruption of circadian rhythm conditions such as continuous night work, shift work, lack of sleep, and jet lag.

In this review study, articles related to the subject were selected and studied from published texts and authoritative sites using keywords muscle molecular clock, exercise performance, circadian rhythm, and phenotype.

The time of sports activities is very important in performance. Despite the timing of the activity, individual preference for doing the activity in the morning or in the evening can be a very important factor on performance. According to the reviewed studies, most of the sports performance such as strength, speed, endurance, accuracy, recovery ability, harmony, etc., were better in the evening and early night in the athletes of different team and individual disciplines. This superiority in the evening can be attributed to body temperature, hormone release, circadian rhythm, rest and recovery, etc. In some cases, such as swimming, strength and endurance are better in the morning.

Based on the information collected in this review study, biological and physiological rhythms have an effect on people's physical performance. Despite individual differences and personal preferences in determining training hours, taking into account a specific training time each day and training at the beginning of the day can improve people's performance. Higher body temperature in the evening, increasing the level of secretion of hormones such as cortisol and testosterone, etc. can be one of the factors affecting the better performance of athletes in the evening. But depending on the type of activity, skill level, gender of the athletes and individual differences, the time to perform the activity for better performance can vary. In addition to the mentioned cases, individual preference to perform activities during the day or night is an important factor in improving performance.

Based on the information collected in this review study, biological and physiological rhythms have effect on people's physical performance. Despite individual differences and personal preferences in determining training hours, by considering a specific training time each day and training at the beginning of the day, people's performance can be improved.

Skeletal muscle has a high plasticity in adapting to stressors such as contractive activity (strength training, endurance training, electrical and neuromuscular stimulation), loading conditions (unloading, diseases, lack of movement, and spaceflight), and interventions and environmental factors (hypoxia). Existing evidence shows that skeletal muscle fibers have a unique ability to remember their previous chronic contractile activity and in response to the training period, even after a prolonged lack of training, show faster growth. Scientists have called this phenomenon muscle memory. Primary studies attributed this phenomenon to motor learning through the central nervous system, but subsequent studies suggest that muscle memory may be associated with the content of skeletal muscle nuclei. Although the biological basis of muscle theory is not established correctly, one of the possible mechanisms is that the primary period of exercise training leads to an increase in myonuclei and these nuclei remain stable even after a long period of detraining in skeletal muscle. Therefore, following the retraining period, a muscle whose nuclei have increased in the initial training period can grow more efficiently and show a faster hypertrophy response. However, later studies showed that myonuclei might not be stable and may be destroyed after periods of detraining. Therefore, recent studies investigated other mechanisms such as epigenetics in justifying the theory of muscle memory. In general, the available evidence does not support the stability of myonuclei in the theory of muscle memory, and it is suggested that other evidence such as epigenetics be examined by researchers to justify this theory.

Growth and differentiation factor 11 (GDF11) is a protein with anti-aging potential and may play a role in regulation of skeletal muscle mass. However, to date little is known about the effect of exercise training on it. Therefore, in this study, using 24 aged male Wistar rats, the effect of eight-week resistance and aerobic training on GDF11 levels in tibialis anterior (TA) muscle was investigated. The resistance training protocol included 10-15 reps of ladder climbing with a resistance (attached to their tail base) equal to 55-85% of their maximum carrying capacity, 3 sessions per week), and the aerobic training protocol included 30-45 minutes of swimming exercise with a weight equal to 3-6% of their body weight (attached to their tail), 4 sessions per week. One way analysis of variance was used to test the difference between group  (α < 0.05). The result showed that resistance and aerobic training increased TA muscle levels of GDF11 by 5.3% and 1.6%, respectively. Moreover, resistance and aerobic exercise led to an increase of 9.5% and 4% in TA muscle mass, respectively. However, the amount of changes was not statistically significant in either case (p>0.05). Based on the findings of the present study, especially those of resistance training, it seems that GDF11 is involved in exercise training-induced upregulation of skeletal muscle mass in aged rats.

Hyperglycemia occurring in the diabetic condition can cause apoptosis via the mitochondrial pathway with higher cell death protein expression. Probiotics are viable microorganisms which confer health benefits to the host and have anti-diabetic and antioxidant effects. Also, there are some evidences that exercise may affect the signaling pathways of skeletal muscle apoptosis. The aim of this study was to examine the aerobic exercise training and probiotic supplementation effects on blood glucose levels and caspase-3 gene expression of the soleus muscle in diabetic rats-induced by streptozotocin.

 40male Wistar rats (weight: 250-270 gr; age: eight weeks) were selected and divided into five groups: control+normal (N), control+diabetic (CD), diabetic+probiotics (SCD), diabetic+aerobic training (TD), and TD+probiotics (STD). Rats were made diabetic using streptozotocin (45 mg/kg). The rats in the training groups aerobically exercised using a treadmill at intensity of 60-65% of maximum speed for five weeks and five days per week and received probiotics (2 gr) in drinking tap water (supplemented groups). 48 hours after the last training session, the animals were sacrificed, then the soleus muscle was dissected to evaluate the gene expression of caspase-3 (using the Real Time PCR) and plasma glucose (by the glucose oxidase method). T-test, one-way ANOVA and Scheffe’s post hoc tests were applied for statistical analysis at significance level of p≤0.05.

The results indicated that fasting blood sugar was significantly lower in the TD+probiotics group compared to the other groups (p=0.008). On the other hand, gene expression of caspase-3 was a significantly decreased in diabetic+aerobic training and TD+probiotics (p=0.01) groups.

It appears that aerobic exercise training with the use of probiotics prevents apoptosis in the muscle with the down-regulation of blood glucose.

little is known about the concomitant effects of HIIT and Q10 supplementation in modification of the mitochondorial biogenesis and function in obesity conditions. The aim of this study was to investigate the concomitant effects of HIIT and Q10 supplementation on soleus muscle mitochondorial content as well as NRF2, SIRT-1 and Tfam levels in obese male rarts.

48 rats randomized into six groups of lean, obese reference, obese control, obese+HIIT, obese+Q10 and obese concomitant (HIIT+Q10). Obesity was induced by high fat diet and HIIT) were done for 12 weeks (five sessions/week, with 10 intrval bouts for four min at 85-90% of v VO2 peak each session), while Q10 was consumed 500 mg/kg.bw daily. Data were measuered using western blot and Mitotrackervmethods and were analyzed by one-way ANOVA.

Mitochondorial content (P = 0.049) as well as NRF2 (P = 0.002), SIRT-1 (P = 0.007) and Tfam (P = 0.040) levels were significantly lower in obese control than lean group. Mitochondorial content and SIRT-1 levels of three intervention groups of obese+HIIT (P = 0.001), obese+Q10 (P = 0.001) and obese concomitant (P = 0.001) were significantly higher than obese control group and even could precede lean group values (with exception for mitochondorial content in obese+Q10 group (P = 0.001)). Moreover, only in both groups of obese+HIIT ( P= 0.033), and obese concomitant (P = 0.038), NRF2 levels were significantly higher compared to obese control group. However, in none of the intervention groups the Tfam levels had significant differences compared to obese control group (P > 0.05 in all three cases).

Obesity likely suppresses soleus muscle mitochondorial biogenesis, or at least increases the removal rate of pre-existing mitochondria. However, HIIT as well as Q10 supplementation seems to partially capable to restore this down regulation, with a greater effects expected for HIIT. However, more investigations remain to be done due to lack of similar evidence and study limitations.

Decreased physical activity is associated with poor neuromuscular function for daily activities. Laboratory studies indicate the effect of calcitonin gene-related peptide (CGRP) on neuromuscular activity. The aim of this study was to investigate the effect of a course of moderate-intensity continuous rehabilitation exercises (MCT) on CGRP expression in skeletal muscle of male Wistar rats.

For this purpose, 12 male Wistar rats weighing 200-220 g, with a sleep cycle of 12.12, free access to food and water and ambient temperature of 25±2 ° C were randomly divided into two groups of exercise and control. The training group performed 6 sessions (5 sessions per week) of continuous training with moderate intensity. The conditions of the control group were similar to the training group but they did not exercise. Finally, 48 hours after the last training session, rats were extracted by standard anesthesia, victim and horseshoe muscle method of all mice, and then Western blot method was used to determine the expression of CGRP protein. Significance level was considered p> 0.05.

Statistical findings from the output of independent t-test for CGRP receptor protein expression values showed that the implementation of six weeks of MCT training protocol significantly increased CGRP protein expression in the MCT group compared with the control group (P = 0.048).

These results indicate that the MCT rehabilitation protocol caused that muscle function during endurance activities could be improved by increasing CGRP protein expression.

Intensity and energy expenditure of exercise are most effective factors on substrate oxidation. Involved muscle mass in exercise is an effective factor on substrate oxidation. The aim of the present study was to compare the acute effect of two type of high-intensity interval exercise (HIIE) with same energy expenditure and different involved muscle mass on substrate oxidation, appetite and exercise enjoyment in overweight or obese men.

Ten overweight or obese young men (body mass index: 29.95±2.97 kg.m-2) completed three conditions including Tabata exercise (20 min at approximately 75% VO2max) (TE), ergometer exercise (23 min at approximately 66% VO2max) (EE), and control. The subjects' breathing gases were analyzed by gas analyzer in baseline, during exercise, and during three hours after exercise. The appetite was measured in before, immediately and three hours after exercise. The exercise enjoyment was measured, immediately after exercise.

Fat oxidation during three hours after the TE was significantly higher compared to EE and control (P=0.01) and carbohydrate oxidation during three hours after the TE was significantly lower compared with control condition (P=0.04). There was no significant difference between the two HIIE during three hours after exercise in excess post-exercise oxygen consumption and energy expenditure. However, the respiratory exchange ratio was higher in 0-30, 120-150, 150-180 min, and total of three hours after the TE compared with EE (P values, 0.02, 0.02, 0.02, and 0.05, respectively). Finally, appetite increased regardless of the presence and type of intervention, in three hours after exercise (P=0.01). There was no significant difference between the perceived enjoyment of TE and EE (P = 0.41).

It seems that Tabata exercise, which involves more muscle mass, causes more oxidation of fat after exercise compared to exercise with the same energy expenditure on ergometer in overweight or obese men, despite no difference in appetite and exercise enjoyment.

In recent decades, along with industrialization, improvements in public health and subsequently higher life expectancy indices, population of elderly people has been increased. The elderly ages are very important years of human life, because of progressive degeneration of human body tissues and its very deep impacts on physical performance. One of the most impressive changes is muscular tissue decrement and atrophy of skeletal muscles, so called “sarcopenia”. The disease is so debilitating and causes sever dysfunction, quality of life, and life expectancy of patients. In this article, most important aspects of ageing and muscle fiber changes and training effects on strength, endurance and composition of muscle fibers of elderly people are reviewed.

Autophagy has been introduced as a protective mechanisms in cell in recent years. Regarding to the changes induced in autophagy factors following an acute physical exercise. The purpose of this study was to investigate the changes in autophagy factors in time courses of acute exhaustive endurance exercise in Tibialis Anterior skeletal muscle of BALB/c mice.

Regarding the purpose of the study, 12 BALB/c mice were divided into two groups of exercise and control. Subjects were anatomized immediately and 12 hours after the end of the exercise session. The Real Time-PCR method was used to determine the expression of autophagy factors.

Independent t-test showed significant increases in autophagy activation immediately after exercise and significant decreases 12 hours following acute exhaustive endurance exercise (P≤0.05).

  Our results proposed that significant increases induced in autophagy factors immediately after acute exhaustive exercise. Possible correlations between autophagy activation and changes in oxidative stress, some immunological factors and metabolic responses could be some of mechanisms of autophagy activation following acute exercise.

The aim of this study was to investigate the effect of 8 weeks of sprint interval training (HIIT) on antioxidant capacity, glutathione peroxidase (GPX) and lipid peroxidation, malondialdehide (MDA) of heart, liver and skeletal muscle tissues in male Wistar rats. Thirteen male Wistar rats (weight= 225.88±18.68 g, age= 8 weeks) after one-week familiarization, were randomly divided into 2 groups; Control (n=6) and sprint interval training (n=7). HIIT training protocol included 8 weeks (5 session per week) of running with 30-45 m/min on rodent treadmill (for 1 min with 10 reps and 2 min active rest) at the first week and reached to 75-80 m/min at last three weeks (for 1 min with 7 reps and 3 min active rest). GPX activity was measured by Elisa Kit and MDA level was analyzed by spectrophotometric method. Independed-samples T test results showed that the sprint interval training resulted in a significant decrease in GPX enzyme levels in heart (P=0.001), liver (P=0.002) and skeletal muscle (P=0.006) compared to the control group. Also, MDA levels of heart tissue in training group increased significantly in compare with control group (P=0.001). Based on our finding, different tissues have different oxidative responses to the similar training and HIIT imposes heart tissue on oxidative stress more than skeletal muscle and liver tissue.

Back graund & Cancer cachexia has introduced as anorexia, weight loss, skeletal muscle atrophy, decreases in strength and action in skeletal muscle and fatigue. With considering to antioxidant effects of selenium nano-particles and exercise training, the aim of this study was to examine the effects of aerobic interval exercise training and oral supplementation of selenium nanoparticles on cachexia situation in mice with breat cancer.
Material and 64 mice were randomly divided into 8 group includes Control-Health, Control-Tumor, Training-Healthy, Training-Tumor, Selenium Nanoparticles-Health, Selenium Nanoparticles-Tumor, Selenium Nanoparticles-Training-Health and Selenium Nanoparticles–Training-Tumor. Samples in traning and nanparticles groups have done aerobic interval training and have supplemented with selenium nanoparticles. Muscle mass, body weight, food intake, and weight and inverted performance exercise tests were used to confirm cachexia in animals.
The results of this study have shown that body weight without tomur significantly decreased in mice that supplemented with Selenium nanoparticles (P
skeletal muscle cachexia was observed in current study in breast cancer mice. It seems that selenium nano-particles intensified cachexia situation but combination of exercise training and nano-particles maintained skeletal muscle mass and prevented cachexia.

The phosphatase calcineurin plays a major role in physiological and pathological processes, including immune responses, neuronal plasticity, and skeletal muscle hypertrophy. With considering to effect of this factor in calcium signaling in skeletal muscle, the purpose of present study was assessment of calcineurin activation following of hypertrophic resistance training in flexor hallucis longus muscle of diabetic rats with skeletal muscle atrophy. Rats weighing 250–280 g were divided into the control, training, diabetic control and diabetic training groups. Training groups performed the training consisted of climbing a ladder (1 m) with increasing weight added to the tail in 17 sessions. The interleukin-6 and regulator of calcineurin 1 mRNA expression as calcineurin activation factor were measured in flexor halluces longus muscle using the Real-time Pcr method. The results of this study showed that the expression of regulator of calcineurin 1 was increased with diabetes in muscle of diabetic rats (P

Increase glycogen content of skeletal muscle and liver after endurance-trained has beensuggested. The aim of this study was to investigate the effects of endurance training atdifferent intensities on liver and skeletal muscle glycogen content. Forty male Wistarrats were randomly assigned to control (n = 10), low (18 m/min)(n = 10), moderate (26m/min)(n = 8) and high (34 m/min)(n =10) intensity groups. The training group ranfor 60 min/d, 5d/wk and 0% grade for 12 weeks. 36 hours after the last exercisesession,overnight fast rats were killed liver and gastrocnemius muscle were collectedand measured by spectrophotometeric method. One way ANVOA, appropriatefollowing test were performed, and significance was accepted at P≤0.05. Regardless tointensities, data demonstrated that trained groups had higher liver and lower muscleglycogen contents when compared with control group. Higher liver and muscleglycogen were pronounced in moderate exercise group. It seems that moderate intensityexercise suitable for liver and muscle glycogen improvement.

It suggested that cytokines or other peptides that are produced, expressed and released by muscle fibres (usually during contraction) and exert endocrine effects should be classified as myokines. Many proteins produced by skeletal muscle are dependent upon contraction. Therefore, it is likely that myokines may contribute in the mediation of the health benefits of exercise. Our aim was to investigate effect of intensive resistance exercise training on protein expression of IL-6, IL-1β and TNF-α myokines in skeletal muscle in rats with diabetes. Rats were divided into control, training, streptozotocin induced diabetic and diabetic training groups. Training groups performed for Resistance training consisted of climbing a 1 m ladder with increasing weight added to the tail. Protein expression of myokines in FHL skeletal muscle measured by ELIZA method. The results of this study indicate that training and diabetes interaction was significant for IL-6 in FHL muscle (P<0.05). Also, tumor necrosis factor-alpha (TNF-α) and IL-1β levels were increased by diabetes, but not changed by training. Discussion and In conclusion, we found that in diabetic rats, resistance training decreased muscle IL-6 levels, and preserved FHL muscle mass. It is probably increased inflammatory cytokines in skeletal muscle with resistance training is a mechanism for skeletal muscle adaptation.

Insulin – like growth factor – I (IGF-1) plays a role in the skeletal muscle in the development، growth، repair، and maintenance of the tissues in an autocrine / paracrine as well as endocrine fashion. The aim of the present study was to investigate the response of growth factors to two different training methods. 14 male volunteers were selected and divided randomly into two groups. Group A (plyometric، 7 subjects، age: 20. 86±1. 86 yr، height: 179. 29±4. 23 cm، weight: 74. 56±6. 24 kg) performed plyometric training and group B (combined، 7 subjects، age: 21. 43±1. 72 yr، height: 181. 71±6. 42 cm، weight: 76. 14± 8. 47 kg) performed a combination of resistance training and plyometric training 3 days per week for 8 weeks (4 weeks of resistance training and 4 weeks of plyometric training). Muscle biopsies were obtained from vastus lateralis muscle 3 days before and 7 days after the training. To evaluate muscle power، Bosco (5 and 60 sec.)، Sargent jump and standing long jump tests and to evaluate agility and speed، hexagonal obstacle and 35m dash tests were used respectively. To estimate gene expression of insulin – like growth factor (IGF-1) and mechanical growth factor (MGF)، real time RT – PCR was performed. Paired and independent t tests were used to analyze the data at (P≤ 0. 05). The results showed that in Bosco، Sargent jump، standing long jump، hexagonal obstacle and 35m dash tests، plyometric group had better results than group B. The MGF gene expression decreased insignificantly in group A (by 20. 18%، P≤0. 29) and increased significantly in group B (by 159. 24%، P≤0. 048). IGF-1 gene expression increased significantly in group A (by 133. 83%، P≤0. 04) and increased insignificantly in group B (by 24. 06%، P≤0. 16). It can be concluded that different IGF-1 transcripts (IGF-IEa and MGF) differently respond to various mechanical and metabolic overload strategies in human skeletal muscle.