نشریه فیزیولوژی ورزش و فعالیت بدنی
سال شانزدهم شماره 2 (تابستان 1402)

Resistance training (RT) is an effective program for creating hormonal, functional and structural adaptations, so that manipulation of its variables induces different adaptations. Change in the secretion rate and serum level of hormones due to resistance activity is the main factor in protein synthesis and hypertrophy of skeletal muscles, so the purpose of this study was to investigate hypertrophic and hormonal responses to a session of resistance training with two different protocols in men’s sprint runner.

45 men volunteers (age: 21± 1.7 year, weight: 67.5± 4.35 kg and BMI: 22 ± 1.03 kg/m2) were randomly divided into three groups of 15 people (high-load training, low-load training and control). The training protocol includes seven movements (chest press with barbell, leg extension, biceps barbell, standing shoulder press with barbell, seated leg machine, lat pull down and triceps machine), three sets with 70% 1-RM to failure for training group with high load, seven movements (chest press with barbell, leg extension, biceps barbell, standing shoulder press with barbell, Seated leg machine, lat pull down and triceps machine), three sets with 30% 1-RM to failure for training group with low load, and no activity for control group. Thickness of biceps and vastus lateralis and serum levels of cortisol, IGF-1, testosterone hormones and testosterone/cortisol (T/C) ratio were measured at two stages (pre-test and 30 minute after the RT). The Shapiro–Wilk and the Levine tests were performed to confirm the normality of data distribution and the homogeneity of variances, respectively.

The result of paired-sample t test showed serum concentration of testosterone (P=0.005), IGF-1 (P=0.004), cortisol (P=0.020), T/C (P<0.001), thickness of biceps (P=0.001) and thickness of vastus lateralis (P=0.001) were increased only in RT group with high load compared to the pre-test. Also, the results of ANOVA and Bonferroni’s post hoc test showed the mean of serum concentration of testosterone, IGF-1, cortisol, T/C, thickness of biceps and vastus lateralis in high-load training group was significantly higher than the low-load training (P ≤ 0.05) and control (P ≤ 0.05) groups in the post-test.

Although one session of resistance training with an intensity of 30% of 1RM did not cause a significant change in the serum level of hormones and hypertrophy, it seems that hypertrophy produced after a 70% of 1-RM acute resistance training protocol (and with repetition to failure) appears to be due to hormonal changes due to metabolic stress.

The purpose of this study was to investigate the effect of 30-20-10 interval training on the serum spexin level and lipid profile of obese men in order to measure the effect of physical activity on increasing spexin and improving lipid profile in obese men.

Statistical population of Yezhohesh, 21 obese men (mean age 43.52±9.06 years, weight 108.11±16.42 kg, body mass index 35.42±7.14 kg/m2) who voluntary participated in the present study and were randomly divided into training (11 people) and control (10 people) groups. Training were performed for eight weeks and three sessions per week with the 30-20-10 exercise protocol, including interval training with approximately intensities of 30 seconds with 30%, 20 seconds with 60% and 10 seconds with 90-100% of maximum heart rate. These one-minute training were repeated five times (five minutes) and after 5 repetitions, they rested for two minutes and started the next five repetitions again, and it was repeated in three-four times of running. At the end of the intervention, serum spexin and lipid profile were measured by ELISA method. Within-group changes were analyzed using the dependent t-test. ANCOVA test was used in the data analysis in the pre-test-post-test design with the control group. where pre-test scores were used as covariate. Statistical analyzes were performed at the statistical level of P ≤ 0.05.

By examining the research results, it was found that 10-20-30 interval training caused a significant increase in the amount of spexin in the training group compared to the control group (P=0.010). Also, interval training 10-20-30 causes a significant decrease in the amount of TG variables (P=0.001), LDL-C (P=0.001), cholesterol (P=0.001) and a significant increase in HDL-C. (P=0.001) has been Based on the results, it was found that there is a significant relationship between cholesterol and changes in the serum levels of spexin in obese middle-aged men (P=0.004). Also, there is a significant relationship between changes in serum levels of spexin and changes in some anthropometric indices such as body mass index (P=0.05) and ratio of waist circumference to hip circumference (P=0.005) of obese middle-aged men.

According to the results of the research, a significant increase in serum spexin and HDL-C and a significant decrease in cholesterol, triglyceride and LDL-C, it can be concluded that eight weeks of 30-20-10 interval training has an effect on the levels of the factors mentioned in obese middle-aged men. It can probably increase the serum levels of spexin and improve the lipid profile in these people.

Endometriosis is an estrogen-dependent inflammatory disease that affects 5-10% of women of reproductive age. Different cellular pathways are involved in the pathogenesis of endometriosis. One of these pathways is autophagy. Autophagy is a genetically and evolutionarily conserved programmed process that degrades long-lived cellular proteins and organelles. The aim of this study was to investigate the effect of aerobic exercise and consumption of vitamin B6 and omega-3 on the expression of genes related to autophagy caused by endometriosis in female rats.

In this experimental study, 40 adult male Wistar rats were about eight weeks old. After transferring the rats to the laboratory environment and after two weeks of familiarization with the new environment and creating the endometriosis model, randomly and with an equal number of five rat in each group, they were divided into the control-healthy, endometriosis, sham, endometriosis+exercise, endometriosis+B6, endometriosis+omega-3, endometriosis+exercise groups after creating an endometriosis model+ B6, endometriosis+exercise+omega-3 were categorized. The duration of training in the water was 30 minutes daily until the end of the training period. Two weeks after the creation of the model, omega-3 supplement at a dose of 2 ml/kg to the endometriosis+omega-3 and endometriosis+exercise+omega-3 groups and vitamin B6 supplement at the rate of 60 kg/mg body weight of the rats to the groups endometriosis+B6 and endometriosis+exercise+B6 were taken daily in the form of gavage. One-way analysis of variance was used to analyze the data.

The results showed that the expression levels of LC3-1 and LC3-II genes in the endometriosis group were significantly higher than the healthy control group (P<0.0001) and the expression levels of LC3-1 and LC3-II genes in the group endometriosis+exercise, endometriosis+omega-3, endometriosis+B6, endometriosis+exercise+B6 and endometriosis+exercise+omega-3 were significantly lower than the endometriosis group (P<0.0001). Their values in endometriosis+exercise+B6 and endometriosis+exercise+omega-3 groups were significantly lower than other groups (P<0.0001). Also, the results showed that the expression levels of FOXO3 and LC3-II/I genes in the endometriosis group were significantly lower than in the healthy control group (p<0.0001). The expression levels of FOXO3 and LC3-II/I genes in endometriosis+exercise, endometriosis+omega-3, endometriosis+B6, endometriosis+exercise+B6 and endometriosis+exercise+omega-3 groups were significantly higher than the endometriosis group (P<0.05). Their values in endometriosis+exercise+B6 and endometriosis+exercise+omega-3 groups were significantly higher than other groups (P<0.0001).

In general, the results of the present research indicate that the increased expression of autophagy genes that occurs in endometriosis can be inhibited by regular aerobic exercise such as swimming and omega-3 and B6 supplements. Probably, the pathological disorder caused in autophagy by exercising and supplementing omega-3 and B6 through the regulatory reduction of the expression of lc3-I, lc3-II genes and the increase of the expression of FOXO3 genes and the ratio of lc3-II / lc3-I helps in improving endometriosis.

Cognitive impairment caused by aging has become one of the most common health threats in many countries. Signaling pathways are important moderators of various physiological and pathological processes, and abnormal activation of some signaling pathways can play a role in disease progression in old age. Targets of intracellular signaling in response to exercise have been intensively studied as a measure of cellular processes that occur following specific conditions. It has been found that exercise increases neurogenesis through the induction of neural factors in the hippocampus, which is associated with improved cognitive performance, since long-term exercise can improve the age-related impairment in hippocampal neurogenesis. The aim of this study was to evaluate the effect of high-intensity interval swimming training on CREB and ERK proteins of hippocampus tissue in elderly rats.

In this experimental study, 12 aged male Sprague-Dawley rats (20 months old and average weight 300-450 gr) were placed in two control groups (n= 6 rats) and high-intensity interval swimming training (n= 6 rats). Rats in the training group performed high-intensity interval training (HIIT), including 14 times of 20 seconds of swimming with 10 seconds of rest between each time. The exercise program was carried out for six weeks (three days a week, one day in between). 48 hours after the last training session, rats were anesthetized and immediately, using a surgical blade, the skull was split and the brain was carefully removed. The healthy brain was divided into two halves by a surgical blade, and according to the coordinates of the hippocampus, the hippocampal sinus was separated from the limbic system with the help of a clean atlas. The content of cAMP-response element binding protein (CREB) and Extracellular signal-regulated protein kinases 1 and 2 (ERK) proteins in hippocampal tissue was measured by Western blotting. Data were analyzed using independent t-test at the P <0.05.

The results showed that the protein content of ERK and CREB in the hippocampus of elderly rats after six weeks of training was significantly higher (P=0.03 and P=0.001, respectively) than untrained rats.

According to the results of high-intensity interval swimming training leads to a significant increase in the content of cAMP-response element binding protein and Extracellular signal-regulated protein kinases 1 and 2 of the hippocampus tissue in aged rats, so probably high-intensity interval swimming training can help improve factors involved in cognitive ability during aging.

In contemporary modern societies a lot of people suffer from reproductive system dysfunction and infertility. Various factors such as sedentariness, some diseases and medicines play a role in incidence of reproductive dysfunction, which can lead to decreased reproductive capacity. One of the main mechanisms of which is the increased free radical’s production and oxidative stress in testis. Sprint interval training (SIT) is one of the most time-efficient types of exercise comparing to other exercise methods, which could be used to promote physical activity level. The aim of the present study was to determine the effect of SIT on testis oxidant-antioxidant status and some reproductive indices in adult Wistar rats.

In this experimental study, 16 adult male Wistar rats wereobtained and randomly divided into: 1) control and 2) training groups. Then, the training group practiced 3 times a week for eight weeks. Forty-eight hours after the last exercise session, the rats' testis were removed after anesthesia and transferred to the laboratory and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX), as well as total antioxidant capacity (TAC) and malondialdehyde (MDA) levels were assessed. Moreover, main reproductive function indices including tubular differentiation index (TDI), spermiogenesis index (SI), and cumulative index (RI) were determined. Data were analyzed using independent samples t-test at the alpha = 0.05. 

The statistical analysis revealed that the MDA level of the testis in the training group was significantly higher than the control group (P<0.001). There was no significant difference between groups in terms of the SOD activity and TAC. However, in the training group the GPX activity level was significantly higher comparing to the control group (P<0.05). Moreover, the number of Leydig cells, TDI, and RI in the training group were significantly lower in comparison with the control group (P˂0.05); Nevertheless, no significant difference was observed between groups in terms of SI (P>0.05).

SIT may increase oxidative stress in the testicular tissue and negatively affect the main spermatogenic indices in testis, which can lead to reproductive dysfunction. Conducting more research in this area while controlling the other influential factors and training variables (intensity, duration, and volume) is recommended.

Resistance training is the foundation for increasing muscular strength as well as cardiorespiratory and metabolic fitness and increasing or preserving the capacity to produce power. These resistance training benefits are relevant to the health of the general population and also elite and recreational athletes; particularly those undergoing rehabilitation and as a means of protecting against sports injuries. However, the optimal relationship between resistance training intensity and subsequent physiological improvements remains to be defined. Over the past few decades, the ‘Critical Power’ (CP) concept exemplifies the link between fatigue or exhaustion and performance. In this regard, sports scientists and human physiologists have always used this concept as a link between the development of fatigue/exhaustion (and its mechanistic portents) and exercise performance as a means to prescribe efficient training programs and monitor progress. The present study aimed to a comparison of 1- repetition maximum and the number of repetitions until exhaustion during a squat movement based on two and three critical power components modeling in trained women

Seven trained women (age: 20.11 ± 1.15 years, body mass index: 19.6 93 0.93) Performed Six sets of barbell squats at different intensities based on the percentage of 1-repetition maximum, On six separate days with a rest of at least 24 hours. The weights were selected so the activity lasted about 3-12 minutes. Total activity time to exhaustion and movement rate was estimated using a Stopwatch and distance using Kinovea software.

A linear two-parameter model of CP was accurately able to model exhaustive squatting data based on the plotting total work accomplished versus time-to-exhaustion (r2=0.89±0.09) and paired samples t-tests demonstrated that the actual number of repetitions to failure was not different from the predicted values (P > 0.05). The hyperbolic three-parameter model of CP was also able to model these data based on plotting time-to-exhaustion against total output power (0.90±0.06) and there was also no considerable difference between the actual number of repetitions to failure and those predicted by this model (P > 0.05). Additionally, there weren’t any significant differences between the measured one-repetition maximum and those predicted by the hyperbolic model (P > 0.05). However, the linear two-parameter model was not able to predict one repetition maximum (p<0.05). There was no significant difference between the predicted values of 1-repetition maximum based on hyperbolic modeling and the values measured using the Brzycki method (p<0.05). However, the two-component linear model was not able to predict this variable (P < 0.05).

The two-component linear and three-component hyperbolic models can be generalized to the squat movement to exhaustion. These models also have a high ability to predict the number of repetitions to the exhaustion in squat movement. However, 1 repetition maximum was predictable only with the hyperbolic three-component model.

Despite the advances in modern medicine, drugs and medical technology, stroke diseases cause significant complications to people and always result in a decrease in performance, working memory and muscle strength. The aim of the present study was to investigate the effect of fall-proof training on functional capacities, working memory and Muscle strength of the elderly with stroke.

24 elderly patients suffering from a stroke were divided into two experimentally equal groups and control. The experimental group performed fall-proof exercises for eight weeks, and the control group did not perform any intervention. Training session consisted of 10 minutes of warm-up and stretching, 15 minutes of strength training, 25 minutes of multi-sensory system balance training, the center of gravity control, and posture strategies. In this study, to evaluate the functional capacity of the subjects, from three tests including: get up and go test, a 6-minute walking test, and 8-foot walking agility test, to evaluate working memory using the Wechsler working memory software and to evaluate muscle strength two tests of 30 seconds of lateral climbing and 30 seconds of sitting to standing were used.

Working memory (P = 0.002), stand up and go test (P < 0.001), 6-minute walk test (P = 0.020), 8-foot walk agility test (017 P = 0.01) and the 30 second lateral up test (P = 0.013) had a significant difference in the two experimental and control groups. Working memory (P = 0.001), stand up and go test (P < 0.001), 6-minute walk test (P = 0.009) and 8-feet walk agility test (P = 0.009), 30 seconds of sit-to-stand (P = 0.032) and 30-s Lateral Step Up Test (P = 0.013) in the experimental group increase significantly in the post-test stage compared to the pre-test. Also, the intra-group test did not show any significant difference in any of the variables in the control group in the post-test compared to the pre-test. 

The results showed that fall-proof exercises have led to an increase in working memory, functional index and muscle strength in the elderly with stroke. Due to the multi-dimensional effects of fall-proof exercises and the multifactorial nature of stroke, fall-proof exercises can be used in rehabilitation programs for the elderly with stroke.

  Variable resistance training (VRT) is a type of resistance training that helps to improve muscle strength and function through extra resistance such as elastic bands and chains. The comparison of the effect of constant resistance training (CRT) versus VRT on hormonal response has not been fully studied. So, this study investigated the acute and chronic effects of VRT versus CRT on the salivary concentration of testosterone, growth hormone, and cortisol in trained men.

 30 young resistance-trained men were recruited for this study and were randomly assigned to three groups including VRT, CRT, and control. Both training groups performed an exercise protocol with an intensity of 65 to 85% of 1RM for 10 weeks and 3 sets (three sessions per week). The training included the main upper and lower extremity exercises and the rest period between the sets and exercises was 1 and 2-3 minutes respectively.In addition, the VRT  group used 7.5 kg chains as an external variable resistance. Oral saliva samples were collected before and after the first session (acute response) and the last session (chronic response) and then analyzed by ELISA method. Inter-group changes were analyzed by repeated measures analysis of variance and Bonferroni's post hoc test. The significance level was also considered equal to P £ 0.05.

a significant group×time interaction was observed only for the acute response of salivary testosterone (P = 0.003). So, a significant increase was observed in the salivary of testosterone in the VRT compared to CRT (P = 0.001) and control (P = 0.003), although no significant differences were observed for cortisol (P=0.64), growth hormone (P = 0.52)  and testosterone to growth hormone (P = 0.49). Also, no significant group×time interaction was observed for testosterone (P = 0.377), cortisol (P=0.57), testosterone to cortisol ratio (P = 0.91), and growth hormone (P = 0.200) in chronic response (P > 0.05).

The results showed that a session of VRT caused a significant increase in testosterone hormone immediately after exercise, but 10 weeks of VRT or CRT had no significant effect on the levels of testosterone, cortisol, and growth. It seems that if VRT is performed with higher intensity or volume, additional hormonal responses will occur as a result of exercise, and therefore the effectiveness of the exercise will promote.

Repeated exercise on sand may lead to overreaching due to higher energy costs than on hard surfaces. Therefore, it will be necessary to create variety in training. Tabata training is a type of high-intensity interval training (HIIT), which has been reported to improve some physical fitness factors in team sport players. However, no research has been done regarding its effects on the fitness of beach soccer players. Thus, the aim of the present study was to compare the effect of six weeks of Tabata training on indoor hardcourt vs. sand on some physical fitness factors and the structure and function of the left ventricle in elite beach soccer players.

Sixteen players from one of the Iran Premier Beach Soccer League teams were randomly divided into two equal groups including the sand group and the indoor group. Except for the type of training surface, other training variables were similar between the groups. Each exercise set was performed for 4 min (20 s exercise:10 s rest). The protocol was performed in three sessions a week and the duration of each session was 34 to 39 minutes (7 to 8 sets). Cardiac variables (two-dimensional echocardiography) and physical fitness factors were measured at 72 h and 48 h, respectively, before and after the training period. Moreover, the food consumed by the players on the test days was similar. The analysis of covariance (ANCOVA) test was used to determine the differences between the groups at P < 0.05.

The increase in stroke volume (SV; P < 0.001) and the left ventricular end-diastolic volume (P = 0.003), and the decrease in the relative left ventricular posterior wall thickness (P = 0.042) were significantly higher in the sand group than in the indoor group. Except for peak anaerobic power in the indoor group (P = 0.604), the improvement observed in other physical fitness factors was significant in both groups (P < 0.05). However, no significant difference was observed between the groups in in terms of relative VO2max (P = 0.58), peak (P = 0.134), minimum (P = 0.913), and average (P = 0.5) anaerobic power, explosive power (P = 0.702), 30-m sprint (P = 0.23) and agility (P = 0.884).

Compared to indoor hardcourt, it seems that six weeks of Tabata training on sand increases the SV of elite beach soccer players through a greater venous return to the heart. However, no difference was observed between training on sand or indoor hardcourt in terms of aerobic power, anaerobic power parameters, explosive power, speed of movement, and agility performance. Therefore, the use of Tabata training protocol on a standard indoor hardcourt is recommended to create a variety of conditioning programs for beach soccer players or in situations where there is no access to a sand surface.

Endothelial dysfunction plays an important role in the development of cardiovascular diseases. Exercise training may lead to improved endothelial function. However, the effect of resistance training on endothelial function is not clearly understood. In addition, the age and health status of individuals may also play a role in endothelial function, and these factors have not been investigated in endothelial response to resistance training. Therefore, the aim of the present meta-analysis is to investigate the effect of resistance training on endothelial function in young and older adults with and without chronic diseases.

Main databases including PubMed and Web of Science were searched through January 13, 2023, for resistance training studies on the FMD index. The inclusion criteria for the current research included studies with an exercise training group, human subjects with an average age older than 18 years, measuring endothelial function using FMD, and published in English and Persian language journals. Weighted mean difference (WMD) and 95% confidence interval were used to determine the effect size using CMA2 software. The level of heterogeneity was assessed using the I2 test and the publication bias was also assessed with Egger's test. Subgroup analyses were performed for age (elderly adults including people over 50 years old and young adults including people under 50 years old), health status (with chronic disease and healthy), and type of study (one-group and two-group). All analyzes were performed using CMA2 software.

Twenty-one studies including 701 participants were included in the meta-analysis. The results of data analysis showed that resistance training resulted in a significant increase in FMD [2.07, (CI: 1.26 to 2.88) P = 0.001]. Examination of heterogeneity using the I2 test showed that there was a significant heterogeneity (I2=82.92, p=0.001), while Egger's test results (p=0.73) did not confirm the publication bias. Subgroup analysis based on age showed that resistance training in both groups of young [WMD: 2.06, P = 0.001] and older [WMD: 1.87, P = 0.001] individuals leads to an increase in FMD. In addition, resistance training in both groups of healthy [WMD: 1.770 P = 0.001] and patients [WMD: 2.406 P = 0.001] individuals lead to an increase in FMD. In addition, the analysis based on the type of study showed that FMD is increased in both single-group [WMD: 1.18, P = 0.029] and two-group [WMD:2.51, P  =0.001] studies.

In general, the main findings of the present meta-analysis show that resistance training is an effective exercise intervention for improving endothelial function, whose beneficial effects occur independently of the age and health status of adults. Therefore, resistance training should be included in the exercise program for adults.