Differences in the Impact of Various Types of Exercise on Irisin Levels: A Systematic Review and Meta-Analysis.

Background: Irisin, a myokine that is responsive to exercise, induces significant changes in subcutaneous adipose tissue. By promoting the browning of white fat tissue, it enhances energy expenditure, thereby addressing overweight and obesity. This systematic review and meta-analysis aimed to compare the effects of different types of physical exercises on irisin levels in overweight and obese adults. Methods: Specifically, the review focused on studies involving obese or overweight individuals who participated in exercise training for a minimum of 8 weeks, with measured and reported changes in serum irisin levels compared to a control group. Data were collected from four databases (Google Scholar, ISI Web of Science Core Collection, PubMed, and Scopus). The risk of bias was assessed using the Begg and Egger tests, and the results were synthesized. Results: Initial searches identified 560 titles, out of which only seven met the criteria for inclusion in the systematic review. Statistical analysis demonstrated a significant increase in serum irisin concentration (SMD = 0.957, P = 0.005) among obese and overweight individuals who engaged in exercise, compared to the passive control group. High-intensity interval training (HIIT) (SMD = 1.229, P < 0.001) had a more pronounced effect on increasing serum irisin levels than other exercise protocols. Furthermore, the effectiveness of exercise varied based on the participants' weight status (significant changes for overweight individuals; P < 0.001 and insignificant changes for obese individuals; P = 0.1), age (significant changes for those under 40 years old; P < 0.001 and insignificant changes for those over 40 years old; P = 0.322), and gender (significant changes for men; P < 0.001 and insignificant changes for women; P = 0.285). Conclusions: Consequently, exercise can elevate serum irisin levels, leading to alterations in adipose tissue phenotype and thermogenesis, ultimately contributing to weight reduction in obese and overweight individuals.

High-Protein Diets during either Resistance or Concurrent Training Have No Detrimental Effect on Bone Parameters in Resistance-Trained Males.

BACKGROUND: The effects of combining resistance training (RT) and concurrent training (CT; resistance + endurance training) with varied protein doses on bone measures remain poorly understood. Hence, we conducted a comparison of the impacts of two high-protein diets (1.6 or 3.2 g kg-1 d-1) over 16 weeks in resistance-trained males, either with CT or RT alone. METHODS: A total of forty-eight males, all of whom were resistance-trained, had the following demographics: 26.6 ± 6 years, body mass index: 25.6 ± 2.9 kg m-2 administered either 3.2 g kg-1 d-1 protein (CT2; n = 12; RT2; n = 12) or 1.6 g kg-1 d-1 protein (CT1; n = 12; RT1; n = 12) during 16 weeks (four sessions·w-1). Bone parameters were assessed pre- and post-intervention. RESULTS: There was no significant interaction between the intervention group and time for the legs, arms, ribs, or pelvis area BMC and BMD (p > 0.05). For the BMD of the pelvis and the BMC of the right ribs, however, there were significant time effects noted (p < 0.05). Furthermore, there was a significant interaction between the intervention group and time in the lumbar and thoracic spines, with a particular time effect noted for the thoracic spine region (p < 0.05). The regional differences in skeletal responses to the intervention are highlighted by these data. CONCLUSION: Our findings show that the intake of two high-protein diets combined with RT and CT during 16 weeks had no adverse effects on bone tissue parameters. While these findings indicate that protein intake between 2 and 3 times the current RDI does not promote bone demineralization when consumed in conjunction with exercise, future studies investigating the long-term effects of chronic high protein intake on bone tissue health are warranted.

The Effect of 4 Weeks Aerobic Exercise Training with Detraining Courses in Various Prevention Phases on BCl-2 and BAX Genes Expression and Proteins.

Background: The aim of this study was to investigate the effect of aerobic exercise with detraining in different phases of prevention on BCL2 Associated X (BAX) and B-cell lymphoma 2 (BCl-2) gene expression and proteins. Methods: For this purpose, 32 female Balb-c mice (18-20 g) were purchased and randomly assigned to primordial prevention (A), primary prevention (B), secondary prevention (C), and control (D). A group performed aerobic exercise for 4 weeks, after 4T1 cells injection detrained for 8 weeks. Group B performed aerobic exercise for 4 weeks immediately after injecting 4T1 cells and then detrained for 4 weeks. In C group, the 4T1 cells were first injected and did not perform any activity for 4 weeks, followed by 4 weeks of aerobic exercise. Forty-eight hours after the last training session and detraining courses, after anesthesia, sacrificing, and tissue removal, were performed. Reverse transcription polymerase chain reaction (RT PCR) was used to measure gene expression and Western blot (WB) was used to measure protein content. One-way Analysis of variance (ANOVA) test was used to analyze data. Results: The results showed that aerobic exercise in A, B, and C groups compared to D group reduced BCl-2 gene expression and protein and increased BAX gene expression and protein. Conclusions: Therefore, exercise can cause apoptosis in tumor cells by increasing pre-apoptotic factors and decreasing antiapoptotic factors in tumor cells, and consequently improving the disease status.

Effects of 16 weeks of two different high-protein diets with either resistance or concurrent training on body composition, muscular strength and performance, and markers of liver and kidney function in resistance-trained males.

PURPOSE: It is unclear whether resistance (RT) and concurrent training (CT; resistance plus endurance training) combined with different protein intakes have differential effects on muscle hypertrophy, strength, and performance. Therefore, we compared the effects of two high-protein diets (1.6 or 3.2 g.kg-1.d-1) during 16 weeks of either CT or RT alone in resistance-trained males. METHODS: Forty-eight resistance-trained males (age: 26 ± 6 yr, body mass index: 25.6 ± 2.9 kg.m-2) performed 16 weeks (four sessions·w-1) of CT or RT with either 1.6 g.kg-1.d-1 protein (CT1; n = 12; RT1; n = 12) or 3.2 g.kg-1.d-1 protein (CT2; n = 12; RT2; n = 12). Training adaptations were assessed pre-, mid-, and post-intervention. RESULTS: All measures of performance (endurance, vertical jump, and pull-up), lean mass, muscle strength, and power significantly increased post-intervention in all groups, but peak power gains were greater in RT2 compared with RT1 and CT1 (p < .05). VO2max significantly increased in both CT groups (p < .001). Select biochemical markers of kidney and liver function significantly increased within the RT2 and CT2 groups (p < .05), however, no between-group differences were apparent (p > .05). CONCLUSIONS: With the exception of peak power, intake of 1.6 g.kg-1.d-1 of protein appears sufficient to maximize gains in lean mass, muscle strength, performance, and aerobic capacity during both RT and CT without influencing markers of kidney and liver function, indicating this daily protein amount is effective and safely tolerated in young, healthy adults.

The Effects of 4-Week Aerobic Exercise on the Levels of CCl2, CCl5, and their Respective Receptors in Female BALB/C Mice Suffering from Breast Cancer.

Background: The studies reported that chemokines Chemokine (C-C motif) ligand 2 (CCL2) and Chemokine (C-C motif) ligand 5 (CCL5) have tumor-promoting roles in breast cancer (BC). The aim of the present study was to evaluate the effect of 4 weeks of continuous aerobic exercise (AE) on chemokines CCL2 and CCL5 and their relative receptors in animal model of human BC. Materials and Methods: BALB/c mice were divided randomly into four groups included cancer control (CC) and three other groups. The total duration of the experiment was 14 weeks, including 2 weeks of familiarization of mice with treadmills and three of 4-week periods of experiment. Tumor inoculation and formation were performed in the second 4-week period. Group 1 received AE in the first 4-week, Group 2 received AE in the second 4-week and Group 3 in the third 4-week. Results: The CCL2 was reduced significantly in Groups 1, 2, and 3 compared to control (F3,12= 4705, P = 0.0001). In terms of CCL5, a significant decrease was seen only between Group 3 and control. Western blot results showed a significant reduction in C-C chemokine receptor Type 2 (CCR2) between Group 1 versus CC and Group 2 versus CC (F3,20= 1.812, P = 0.004). In terms of C-C chemokine receptor Type 5 (CCR5) a significant decrease was observed between Group 2 versus control and Group 3 versus control (F3,20= 273.3, P = 0.042), (P = 0.004). Conclusion: It can be concluded that 4-week AE significantly reduces the chemokines CCL2 and CCL5 and their respective receptors levels CCR5 and CCR2 in different stages, and it may have an inhibitory effect on tumor growth.

The Effects of 12 Weeks of Concurrent and Combined Training on Inflammatory Markers, Muscular Performance, and Body Composition in Middle-Aged Overweight and Obese Males.

AIM: Previous studies have focused on the order of endurance and resistance training when performing concurrent training (CT). However, no study has compared the effects of combined training with CT orders on inflammatory markers, muscular performance, and body composition in overweight and obese males. Therefore, the purpose of the current study was to compare the effects of 12 weeks of CT and combined training on the aforementioned markers in overweight and obese males. METHODS: Sixty middle-aged overweight and obese males (age 51 ± 4 years) were randomly assigned into one of four groups: endurance followed by resistance training (ER; n = 15), resistance followed by endurance training (RE; n = 15), combined resistance and endurance training (COM), or control (CON; n = 15). Anthropometric, body composition, inflammatory marker, and muscular performance measurements were collected at baseline and after 12 weeks. RESULTS: FFM remained unchanged in all three intervention groups (p > 0.05). Reductions in FM in the RE group were significantly greater than in CON (p = 0.038). The increases in serum concentrations of adiponectin in the RE group were significantly greater than in all other groups (p < 0.05). Increased serum concentrations of CTRP3 in all intervention groups were significantly greater than the CON group (p < 0.05); moreover, the increases in the RE group were significantly greater than CON (p < 0.001). Regarding CTRP5, the increase in RE was significantly greater than COM (p = 0.014). The RE group experienced significantly greater increases in CTRP9 than all other groups (p < 0.05), and the decreases in serum concentrations of CRP and TNF-α were significantly greater in the RE group compared to CON and ER (p < 0.05). Vo2max in the ER group was significantly greater than COM (p = 0.009), and all interventions resulted in higher gains compared to CON (p < 0.05). The increases in leg press strength, chest press strength, lower-body power, and upper-body power in the RE group were significantly greater than in the COM group (p < 0.05). In addition, the increases in chest press strength in the ER group were significantly greater than COM (p = 0.023). CONCLUSIONS: Regardless of training order, CT improved inflammatory markers, body composition, power, and VO2max. Notably, our analysis indicated significantly greater improvements in adiponectin, CTRP5, CTRP9, CRP, and TNF-α levels when RT preceded ET in CT sessions compared to other exercise training sequences. These findings suggested that the order of exercise training may have a significant impact on the effectiveness of CT on inflammatory markers, which has potential implications for exercise prescription and optimization of health-related training outcomes.

The effects of gradual vs. rapid weight loss on serum concentrations of myokines and body composition in overweight and obese females.

Context: Research has shown the modulations of Follistatin (FST) and Myostatin (MST) following weight loss.Objective: We evaluated the effects of gradual weight loss (GWL) and rapid weight loss (RWL) on serum MST, FST, and body composition in overweight and obese females.Materials and methods: Thirty-six overweight and obese females successfully completed the study interventions: GWL (n = 18) or RWL (n = 18). Serum MST and FST concentrations, as well as anthropometric measurements, were collected at baseline and at the conclusion of each weight loss intervention.Results: MST concentration significantly (p < .05) decreased in the GWL; while FST concentration, body fat percentage and skeletal muscle mass significantly declined in both conditions. The loss in skeletal muscle mass was significantly greater in RWL relative to GWL.Discussion and conclusion: GWL was more effective than RWL in preserving skeletal muscle mass in overweight and obese females. Moreover, GWL leads to declines in MST concentrations.

Effects of 12-week moderate aerobic exercise on ROCK2 activity, hs-CRP and glycemic index in obese patients with impaired glucose tolerance.

BACKGROUND: Obesity is a chronic low-grade inflammatory state that is related to prediabetes, increased Rhoassociated kinase 2 (ROCK2) activity and concentration of high-sensitivity C-reactive protein (hs-CRP). Therefore, the study was conducted to investigate the effects of 12-week moderate aerobic exercise on ROCK2 activity, hs-CRP, glycosylated hemoglobin A1C (HbA1c), and glycemic index in obese patients with impaired glucose tolerance. METHODS: In a quasi-experimental design with pre and post-test, 42 obese men with prediabetes [mean±SD, age: 44.73 ± 3.30 years, body mass index (BMI): 33.22 ± 2.05 kg/m2, HbA1c: 6.29% ± 0.75] were allocated into two randomized homogeneous groups: Aerobic training group (AT, n = 22) or control group (C, n = 20). Exercise group performed a moderate aerobic exercise program three sessions per week, 60 min per session for 12 weeks. Body mass, BMI, maximal oxygen consumption (VO2max), serum levels of fasting blood glucose (FBG), insulin, insulin resistance (HOMA-IR), homeostasis model assessment of ß-cell function (HOMA-B); HbA1c, hs-CRP, or ROCK2 activity were measured before and after the study period. The data were analyzed using repeated measures ANOVA 2 × 2 and paired sample t-test at a significant level of p < 0.05. RESULTS: AT caused a significant reduction in body mass (p ≤ 0.001), BMI (p = 0.04), HOMA-B (p = 0.003), serum levels of FBG (p = 0.002), HbA1c (p = 0.039), hs-CRP (p ≤ 0.0001), and ROCK2 activity (p = 0.001). In contrast, in the same group, a significant increase was observed in VO2max (p = 0.04). CONCLUSION: The results of this study showed that moderate aerobic exercise was an effective and safe method to prevent type 2 diabetes and cardiovascular diseases in obese men with prediabetes by improving glucose metabolism, reduction of body mass, ROCK2 activity and serum levels of hs-CRP.

Effects of 8-Week Noncontinuous Aerobic Exercise on the Levels of CCL2, CCL5, and their Respective Receptors in Female BALB/C Mice Suffering from Breast Cancer.

Background: Recently, the importance of chemokines and their receptors in carcinogenesis and the protective role of aerobic exercise in primary cancer development and progression is highlighted. Based on the facts that endurance exercise may result in hypoxia condition, and in addition, the effect of exercise therapy on the levels of CCL2, CCR2, and their related receptors in breast cancer (BC) model has not been investigated so far, therefore we aimed to evaluate the effect of eight-week noncontinuous aerobic training on the levels of CCL2, CCL5, and their related receptors; CCR2 and CCR5 in female BALB/C mice with BC. Methods: Thirty-two BALB/C mice (4-5 weeks old) were randomly divided to four 8-member groups of control and experimental. The experimental group received 8 weeks of noncontinuous aerobic exercises (AEs) while the control group did not receive any exercises during these 8 weeks. After last of experiment, 5 ml of blood was taken from each rat's lower inferior vein. The plasma levels of CCL2 and CCL5 were measured by ELISA and CCR2 and CCR5 by western blot. Tumor volume also measured in each step. Data were analyzed using the ANOVA test and the SPSS v. 0.24 Software. Results: After 8 weeks of participation in noncontinuous AEs, a statistically significant decrease was made between the control and experimental groups in terms of CCL2, CCL5, and CCR2 levels, as well as tumor volume. However, there was no significant difference between groups in terms of CCR5 level. Conclusions: It can be concluded that the 8 weeks of noncontinuous AEs did not result in CCR5 reduction while resulting in a statistically significant decrease in CCL2, CCL5, CCR2, and tumor volume.

Spirulina supplementation during gradual weight loss in competitive wrestlers.

We aimed to assess the effects of spirulina supplementation during gradual weight loss on serum concentrations of follistatin (FST), myostatin (MST), insulin-like growth factor 1 (IGF-1), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and body composition in competitive wrestlers. Forty competitive wrestlers (age: 22 (sem 2) years) were randomly assigned to one of two groups: gradual weight loss + spirulina (SP; n 20) or gradual weight loss + placebo (PL; n 20). Subjects in both groups lost weight according to a designed diet over 12 d and were required to reduce baseline body mass (BM) by 4%. Subjects in the SP group received two tablets of spirulina, while subjects in the PL received two tablets of placebo before each meal. Concentrations of mentioned serum markers and body composition were measured before and after the interventions. BM (SP = -3·1 kg and PL = -2·9 kg), body fat percentage (BFP) (SP = -2·1 % and PL = -0·6 %), fat mass (FM) (SP = -2·2 kg and PL = -0·9 kg) and skeletal muscle mass (SP = -1·4 kg and PL = -1·5 kg) significantly decreased in both groups (P < 0·05). The changes in BFP and FM were significantly greater in SP compared with the PL group (P < 0·001). Additionally, MST (SP = -0·1 ng/ml), AST (SP = -2·1 u/l) and ALT (SP = -2·7 u/l) concentrations significantly diminished in SP group (P = 0·005), while FST (PL = -0·1 ng/ml) and IGF-1 (PL = -2·6 ng/ml) concentrations significantly decreased in PL group (P < 0·05). Spirulina supplementation during gradual weight loss is beneficial in reducing BFP, FM, MST and liver enzymes while maintaining IGF-1 and FST concentrations in competitive wrestlers.

Long-term aerobic exercise training in type two diabetic patients alters the expression of miRNA-223 and its corresponding target, the P2RY12 receptor, attenuating platelet function.

BACKGROUND: Type two diabetes mellitus (T2DM) patients are prone to develop atherothrombotic events due to platelet hyper-reactivity stemming from platelet miRNA-223 down-regulation and over-expression of its corresponding target, P2RY12. OBJECTIVE: The study sought to determine the effects of long-term aerobic training on the expression levels of miRNA-223 and P2RY12 mRNA, and platelet function in T2DM patients. METHODS: Twenty-four patients with T2DM (age, 60.0±2.8 yrs.) were selected and randomly divided into two groups: aerobic exercise training (AET, n = 12) and control (CON, n = 12). The AET protocol was performed with moderate intensity for 12 weeks, while patients in the CON group followed their usual routine. Weight, body mass index (BMI), peak oxygen consumption (VO2peak), lipid profile, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), insulin resistance index (HOMA-IR), platelet miRNA-223 and P2RY12 expression were measured before and after the period. RESULTS: There was a significant improvement in body weight, BMI, VO2peak, FBG, HbA1c, and HOMA-IR, after 12 weeks of AET (P < 0.01). Platelet aggregation decreased significantly after 12 weeks in the AET group compared with the CON (P < 0.001) group. Platelets' miRNA-223 and P2RY12 were significantly up- and down-regulated after AET in comparison with the CON group (P < 0.05), respectively. Moreover, the relative expression of miRNA-223 and P2RY12 significantly correlated with FBG changes following the intervention. CONCLUSIONS: It can be concluded that long-term moderate-intensity aerobic training might be effective for reducing the occurrence of atherothrombotic events leading to premature death in T2DM patients through the modulation of miRNA-223, P2RY12 receptor expression, and platelet function.

Can vitamin C supplementation reverse the effects of exercise training in polluted air on oxidative stress markers? A randomized controlled trial.

BACKGROUND: Air pollution and long-term aerobic exercise are diversely associated with cardiovascular disease (CVD) and mortality. However, the simultaneous effect of exercise in polluted air and vitamin C on oxidative stress markers is less clear. In this study, the effect of these variables on oxidative stress markers was investigated in rats. METHODS: The study was conducted on 50 male rats. The rats were divided into 5 groups consisting of exercise, exercise with vitamin C, exercise in polluted air, exercise in polluted air with vitamin C, and control group. Animals in the exercise groups exercised on a treadmill for 12 weeks, 5 days/week, 30 minutes/day, at 50-70% of the maximum speed. Animals in the vitamin C groups received 20 mg/kg/day vitamin C orally. After 12 weeks of intervention, 2.5 ml of blood was taken from the rats' apex. Malondialdehyde (MDA) and oxidized low-density lipoprotein (OxLDL) levels were measured using NavandSalamat's Nalondi and Eastbiopharm's OxLDL ELISA kits, respectively. Two-way analysis of variance (ANOVA) was used for data analysis in SPSS software. RESULTS: There were significant differences in MDA and OxLDL levels between all groups after 12 weeks of intervention (P < 0.050). The levels of MDA and OxLDL were significantly higher in the ExPo group compared to the Ex+VitC groups (P < 0.050). However, no significant difference was observed in MDA and OxLDL levels between the vitamin C groups (P > 0.050). CONCLUSION: These findings demonstrate the oxidative stress effects of air pollution, systemically and in the respiratory tract. Moreover, polluted air significantly increased OxLDL levels in both exercise in polluted air groups. Although, vitamin C slightly decreased MDA and OxLDL levels in the ExPo groups, the difference was not significant. Different vitamin C doses could have diverse and maybe significant results.

Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial.

OBJECTIVE: Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. METHODS: Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. RESULTS: Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. CONCLUSIONS: 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

Endurance exercise improves avoidance learning and spatial memory, through changes in genes of GABA and relaxin-3, in rats.

Different exercise patterns, neurotransmitters, and some genes have numerous effects on learning and memory. This research aims to investigate the long-term effects of submaximal aerobic exercise on spatial memory (SM), passive avoidance learning (PAL), levels of serum relaxin-3, gamma-aminobutyric acid (GABA), RLN3 gene, and glutamic acid decarboxylase (GAD65/67 genes) in the brainstem of adult male Wistar rats. Fifty male Wistar rats were randomly divided into five groups: aerobic exercise groups, performed on a treadmill running (TR), for 5 weeks (Ex5, n = 10), 10 weeks (Ex10, n = 10), involuntary running wheel group for 5 weeks (IRW5, n = 10), sham (Sh, n = 10) and control (Co, n = 10). Consequently, SM, PAL, serum relaxin-3, GABA, and GAD65/67 and RLN3 genes were measured by ELISA and PCR. Ex5, Ex10 and IRW5 improved significantly SM (p ≤ 0.05), PAL (p ≤ 0.001) and decreased significantly relaxin-3 (p ≤ 0.001). RLN3 in the brain also decreased. However, it was not significant. GABA and GAD65/GAD67 increased significantly (p ≤ 0.05) in Ex5, Ex10 compared to Sh and Co. Aerobic exercise enhanced SM and PAL in Ex compared to Co and Sh. However, duration and type of exercise affected the level of enhancement. The serum relaxin-3 and RLN3 gene displayed reverse functions compared to GABA and GAD65/67 genes in Ex. Therefore, the changes of neurotransmitters in serum relaxin-3, GABA, and their genes: RLN3 and GAD65/67 respectively, influenced learning and memory meaningfully.

The effects of 14-week betaine supplementation on endocrine markers, body composition and anthropometrics in professional youth soccer players: a double blind, randomized, placebo-controlled trial.

OBJECTIVE: Betaine supplementation may enhance body composition outcomes when supplemented chronically during an exercise program. The purpose of this study was to evaluate the effect of betaine supplementation on development-related hormones, body composition, and anthropometrics in professional youth soccer players during a competitive season. METHODS: Twenty-nine players (age, 15.45 ± 0.25 years) were matched based upon position and then randomly assigned to a betaine group (2 g/day; n = 14, BG) or placebo group (PG, n = 15). All subjects participated in team practices, conditioning, and games. If a subject did not participate in a game, a conditioning protocol was used to ensure workload was standardized throughout the 14-week season. Growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone, cortisol, height, weight, and body composition were assessed at pre-season (P1), mid-season (P2) and post-season (P3). Anthropometric variables were also measured following a one-year follow-up (F). RESULTS: Significant (p < 0.05) group x time interactions were found for testosterone and testosterone to cortisol ratio (T/C). Both variables were greater in BG at P2 and P3 compared to P1, however, the testosterone was less in the PG at P3 compared to P2. There was no significant group by time interactions for GH, IGF-1, lean body mass, or body fat. There was a significant (p < 0.05) group x time interaction in height and weight at F, with the greater increases in BG compared to PG. CONCLUSION: Betaine supplementation increased testosterone levels and T/C ratio in youth professional soccer players during a competitive season. Betaine supplementation had no negative effects on growth (height and weight) and may attenuate reductions in testosterone due to intense training during puberty.

The Effect of Acute Intense Exercise on Activity of Antioxidant Enzymes in Smokers and Non-Smokers.

Acute intense exercise causes significant oxidative stress and consequently an increase in total antioxidant capacity; however, the mechanisms and combined effects of intense exercise and smoking on oxidative stress among active and non-active smokers are not clear. The aim of this study was to investigate the effect of acute intense exercise on antioxidant enzyme activity responses in active and non-active individuals exposed to cigarette smoke. The study included 40 subjects who were equally classified as: smokers that did exercise (SE), smokers that did not do exercise (SnE), non-smokers that did exercise (NSE), and non-smokers that did not do exercise (NSnE). The adjusted Astrand test was used to exhaust the subjects. Salivary enzymes of peroxidase (POX), catalase (CAT), and superoxide dismutase (SOD) were measured, by spectrophotometry methods, at 3 different time points: pre-test (TP1), post-test (TP2), and one hour after finishing the test (TP3). Significant (p < 0.05) group x time interactions were found for the three enzymes. Salivary POX, CAT and SOD increased in all groups from TP1 to TP2 and decreased from TP2 to TP3. Only the NSE showed a significant difference between TP1 to TP3 in POX and SOD by +0.011 ± 0.007 and +0.075 ± 0.020 (U/mL), respectively. The NSE showed significantly higher activity of POX, CAT and SOD in TP2 compared to the other groups. Furthermore, NSE and NSnE had higher activity of POX, CAT and SOD in TP1 and TP3 (p < 0.05) compared with SE and SnE. Only in the NSnE, were no differences observed in CAT compared with SE and SnE in TP3. These results showed that the antioxidant activity at rest and in the recovery time after the acute intense exercise was lower in SE and SnE compared with NSE and NSnE, suggesting that smoking habit may reduce the ameliorating effect of regular physical activity on acute exercise-induced oxidative stress.

Fitness Monitoring in Elite Soccer Players: Group vs. Individual Analyses.

Rabbani, A, Kargarfard, M, and Twist, C. Fitness monitoring in elite soccer players; group vs. individual analyses. J Strength Cond Res 34(11): 3250-3257, 2020-The aims of this study were to (a) examine changes in group and individual HR measures during a submaximal warm-up test, and (b) investigate the relationship between accumulated internal training loads and HR changes during an in-season phase among elite soccer players (n = 14). Before and after an in-season phase (24 days), exercise HR (HRex) and HR recovery (HRR) expressed either as the number of beats recovered (HRR60s) or as the mean HR (HRpost1) during 1 minute of recovery were analyzed. Heart rate measures were expressed as the % of maximal HR. Session rating of perceived exertion (sRPE) was computed for all training/match sessions. Group and individual HR changes were analyzed using magnitude-based inferences. Pearson correlation coefficients were also used to examine the relationships. Group analyses of HR changes revealed there were possibly to likely trivial changes in all HR measures. When analyzing individual data, no substantial change was observed for HRR60s%. However, substantial changes in HRex% and HRpost1% were observed for 4/14 and 5/14 players, respectively. The relationships between HRex% and HRpost1% were nearly perfect (r = 0.90, confidence limits [0.82-0.95]). The associations between changes in HRex% and HRpost1% were also nearly perfect (r = 0.92, 0.80-0.97). A very large inverse correlation was observed between HRex% and accumulated sRPE (r = -0.75, -0.44 to -0.90). This study highlights the value of conducting individual vs. group aerobic fitness monitoring. This study also showed the importance of how HRR is reported when aerobic fitness monitoring of elite soccer players.

Combined Small-Sided Game and High-Intensity Interval Training in Soccer Players: The Effect of Exercise Order.

The aim of the present study was to compare combined small-sided game (SSG) and high-intensity interval training (HIT) with different order. Twenty-one semi-professional soccer players were divided into two groups: SSG+HIT (n = 10) and HIT+SSG (n = 11), and underwent similar four-week training programs. Players completed the 30-15 Intermittent Fitness Test (30-15IFT) before and after the experiment; maximum speed (VIFT) was recorded. During the experiment, seven sessions of SSG (3 vs 3) and HIT (15"-15" with 95-100% VIFT) were implemented. Weekly accumulated training loads for both groups during the experiment were similar. Moderate improvements in VIFT were observed in both SSG+HIT (+6.2%, 90% confidence limits, [CL] 4.6; 7.7 and Effect Size, [ES] +0.96) and HIT+SSG (+6.9%, 90% CL 4.6; 9.3 and ES +0.97) groups. Between-group difference in changes of VIFT was trivial (+0.7%, 90% CL -1.8; 3.3 and ES +0.11). Combining SSG and HIT in different order elicited the same enhancement in high-intensity intermittent performance in soccer players.

Session-To-Session Variations of External Load Measures of Youth Soccer Players in Medium-Sided Games.

The aim of this study was to analyze the variability of time-motion variables during five vs. five games when completed within the same session as, and between, two different sessions. Ten under-19 male soccer players (18.27 ± 0.47 years old) participated in this study. The five vs. five matches (3 × 5 min) were played twice with a 3-day interval of rest in the same week. Moderate between-session variations were observed for TD (total distance) (range coefficient of variation (CV), 6.9; 8.3%, confidence interval (CI), (5.0; 14.0), standardized typical error (STE), 0.68; 1.06, (0.64; 1.75)) and RD (running distance) (range CV, 53.3; 145.7%, (36.6; 338.9), STE, 0.83; 1.09, (0.60; 1.76)). PL (player load) showed small variations (range CV, 4.9; 6.0%, [3.6; 10.1], STE, 0.37; 0.43, (0.27; 0.71)). In within-session analyses for examining the differences between sets, a small decrease was observed in RD in set 3 versus set 2 (-14.8%, 90% CI (-32.1; 6.9%); standardized difference (ES): -0.39 (0.95; 0.16)). TD decreased with moderate (-3.5%, (-6.8; -0.1%); ES: -0.65(-1.30; -0.01)) and large (-8.2%, (-11.4; -4.9%); ES: -1.58(-2.24; -0.92)) effects in sets 2 and 3, respectively, versus set 1. Our results suggest that PL is the most stable performance variable. It was also verified that measures had a progressive decreasing tendency within a session.

Effects of food restriction and/or aerobic exercise on the GLUT4 in type 2 diabetic male rats.

BACKGROUND: The aim of present study was to compare the effects of negative energy balance with food restriction and/or aerobic exercise on the glucose, insulin, and GLUT4 levels in diabetic male rats. METHODS: Fifty-six 10-week old male Wistar rats were randomly assigned to seven groups: a non-diabetic (ND) group and six diabetic groups. After an infusion of type 2 diabetes, the diabetic groups were given labels as well, namely diabetic control (DC) group, exercise (Ex) group, food restriction with standard diet (FRSD) group, food restriction with low-carbohydrate diet (FRLCD) group, food restriction with standard diet combination in exercise (FRSDE) group, and food restriction with low-carbohydrate diet combination in exercise (FRLCDE) group. Further, to induce caloric restriction (CR), food intake was reduced by 20% and given to food restriction consists of both of (FRSD and FRLCD). Hundred percent food consumption for the Ex group was fixed, but instead, 20% of their energy intake in exercise was calculated, and time of daily exercise was determined. Finally, a combination of reduced food intake (10%) and exercise (10%) was applied in each group FRSDE and FRLCDE for 8 weeks. RESULTS: The results showed that type 2 diabetes inductions had reduced glucose, insulin, and GLUT4 gene expression compared to the ND group (P = 0.001). However, there were significant differences in GLUT4 gene expression between groups after 8 weeks of intervention (P = 0.001). A post hoc least significant difference test show that compared to DC group, GLUT4 gene expression level of Ex, FRSDE, and FRLCDE groups was significantly increased 47% (P = 0.004), 60% (P = 0.001), and 65% (P = 0.001), respectively after 8 week of intervention, but it was not significant or with any other diabetic groups (P > 0.05). Moreover, glucose levels were significantly higher in the FRLCDE, FRLCD, FRSD, FRSDE, Ex groups compared with the DC group in the same period (P = 0.0.01). CONCLUSIONS: It was concluded that FRSD and FRLCD combination in regular exercise was elevated of GLUT4 gene expression in type 2 diabetes. These results may help to develop new methods for the treatment of obesity and type 2 diabetes mellitus.