Effects of 12-Week Combined Strength and Endurance Circuit Training Program on Insulin Sensitivity and Retinol-Binding Protein 4 in Women with Insulin-Resistance and Overweight or Mild Obesity: A Randomized Controlled Trial.

Background: Circuit training is an exercise mode, that may include both endurance and resistance components. There are premises that a combination of these two modalities brings additional benefits, particularly in improving insulin sensitivity. The retinol-binding protein 4 (RBP4) may inhibit signaling from insulin metabolic pathways in skeletal muscles, thus developing insulin resistance. This study aimed to evaluate whether moderate intensity circuit training combining strength and endurance exercise induces changes in tissue insulin sensitivity, carbohydrate and lipid metabolism, and serum RBP4 levels in insulin-resistant women. Methods: In this clinical controlled trial women diagnosed with insulin-resistance were randomly divided into two groups. The training group (T) performed circuit training combining strength (50%-80%1RM) and endurance (50%-75%HRR) exercise on five weight and two cardio machines, for 33 minutes, three times per week, for 3 months. Women from the control non-training group (NT) did not change their previous physical activity. At the beginning of the study and after the intervention period, a one-repetition maximum, body mass, and composition, resting heart rate (HR), blood pressure, glucose, insulin, blood lipids, thyroid-stimulating hormone (TSH), insulin-like growth factor-1 (IGF-1), RBP4, and insulin resistance (HOMA-IR) were measured. The results of 27 patients were analyzed using a two-way repeated measures ANOVA. Results: Significant differences in the pattern of change over time between the groups for resting HR (p < 0.010) and total lean mass (p < 0.039) were found. No differences in HOMA-IR, and RBP4 were observed post-study compared to pre-study in the T group. A significant correlation between RBP4 and TSH concentration was found. Conclusion: Twelve-week circuit training combining strength and endurance exercise has minor effects on HOMA-IR, glucose and lipid metabolism, IGF-1, TSH, and RBP4. Although moderate-intensity circuit training is considered safe, its effectiveness in patients with overweight and mild obesity may be insufficient to reduce insulin resistance. Trial Registration: ClinicalTrials.gov: NCT04528693, registered August 23, 2020.

Different Approaches to Ergogenic, Pre-, and Probiotic Supplementation in Sports with Different Metabolism Characteristics: A Mini Review.

Sport disciplines with different metabolic characteristics require different dietary approaches. Bodybuilders or sprinters ("anaerobic" athletes) need a high-protein diet (HPD) in order to activate muscle protein synthesis after exercise-induced muscle damage and use nitric oxide enhancers (such as citrulline and nitrates) to increase vasodilatation, whereas endurance athletes, such as runners or cyclists ("aerobic" athletes), prefer a high-carbohydrate diet (HCHD), which aims to restore the intramuscular glycogen, and supplements containing buffering agents (such as sodium bicarbonate and beta-alanine). In both cases, nutrient absorption, neurotransmitter and immune cell production and muscle recovery depend on gut bacteria and their metabolites. However, there is still insufficient data on the impact of an HPD or HCHD in addition to supplements on "anaerobic" and "aerobic" athletes' gut microbiota and how this impact could be affected by nutritional interventions such as pre- and probiotic therapy. Additionally, little is known about the role of probiotics in the ergogenic effects of supplements. Based on the results of our previous research on an HPD in amateur bodybuilders and an HCHD in amateur cyclists, we reviewed human and animal studies on the effects of popular supplements on gut homeostasis and sport performance.

No changes in the abundance of selected fecal bacteria during increased carbohydrates consumption period associated with the racing season in amateur road cyclists.

Background: Cyclists often use high-carbohydrate, low-fiber diets to optimize the glycogen stores and to avoid the gastrointestinal distress during both, the trainings and the competitions. The impact of such dietary changes on gut microbiota is not fully known. Methods: We assessed the abundances of Faecalibacterium prausnitzii, Akkermansia muciniphila, Bifidobacterium spp., and Bacteroides spp. and the fecal pH in 14 amateur cyclists during the racing season. Eleven healthy men formed the control group. Results: Despite significant differences in the diet composition and physical endurance levels of amateur cyclists before the competition season (1st term) and control group (carbohydrates: 52.2% ± 4.9% vs 41.9% ± 6.6%; VO2max: 56.1 ± 6.0 vs 39.7 ± 7.7; p < 0.01; respectively), we did not observe any significant differences in studied gut bacteria abundances or fecal pH between the groups. Although the cyclists' carbohydrates consumption (2nd term) have increased throughout the season (4.48 g/kg b.w. ± 1.56 vs 5.18 g/kg b.w. ± 1.99; p < 0.05), the studied gut bacteria counts and fecal pH remained unchanged. It seems that the amateur cyclists' diet with increased carbohydrates intake does not alter the gut microbiota, but further research is needed to assess the potential impact of even higher carbohydrates consumption (over 6 g/kg b.w.).

No effects of a 4-week post-exercise sauna bathing on targeted gut microbiota and intestinal barrier function, and hsCRP in healthy men: a pilot randomized controlled trial.

BACKGROUND: Body temperature fluctuations induced by acute exercise bouts may influence the intestinal barrier with related effects on epithelial permeability, immune responses, and release of metabolites produced by the gut microbiota. This study evaluated the effects of post-exercise sauna bathing in young men undergoing endurance training on gut bacteria inflammation and intestinal barrier function. METHODS: Fifteen (15) untrained males aged 22 ± 1.5 years were randomly assigned to exercise training (ET) with or without post-exercise sauna treatments (S). Participants in the group ET + S (n = 8) exercised 60 min, 3 times per week, on a bicycle ergometer followed by a 30-min dry Finish sauna treatment. The control group (ET, n = 7) engaged in the same exercise training program without the sauna treatments. Blood and stool samples were collected before and after the 4-week training program. Blood samples were analysed for the concentration of high-sensitivity C-reactive protein (hsCRP) and complete blood counts. Stool samples were analysed for pH, quantitative and qualitative measures of targeted bacteria, zonulin, and secretory immunoglobulin A. RESULTS: Interaction effects revealed no differences in the pattern of change over time between groups for the abundance of selected gut microbiome bacteria and stool pH, zonulin, sIgA, and hsCRP. Pre- and post-study fecal concentrations of Bifidobacterium spp., Faecalibacterium prausnitzii, and Akkermansia muciniphila were below reference values for these bacteria in both groups. CONCLUSIONS: The combination of 4-weeks exercise followed by passive heat exposure did not have a measurable influence on targeted gut microbiota, intestinal barrier function, and hsCRP levels in young males. TRIAL REGISTRATION: The study was retrospectively registered in the clinical trials registry (Clinicaltrials.gov) under the trial registration number: NCT05277597. Release Date: March 11, 2022.

The Effect of Endurance and Endurance-Strength Training on Bone Health and Body Composition in Centrally Obese Women-A Randomised Pilot Trial.

There is no consensus exercise programme to reduce body weight and improve body composition simultaneously preventing bone loss or stimulating osteogenesis. This pilot study compared the effect of endurance and endurance-strength training on body composition and bone metabolism in centrally obese women. Recruited subjects were randomly assigned to three-month endurance (n = 22) or endurance-strength training (n = 22). Body composition, bone mineral density (BMD) and content (BMC) were assessed before and after the intervention and markers of bone formation and resorption were measured. Both training significantly decreased fat mass; however, endurance-strength training had a more favourable effect on lean mass for the gynoid area (p = 0.0211) and legs (p = 0.0381). Endurance training significantly decreased total body BMC and BMD (p = 0.0440 and p = 0.0300), whereas endurance-strength training only reduced BMD (p = 0.0063). Changes in densitometric parameters did not differ between the groups but endurance training increased osteocalcin levels (p = 0.04845), while endurance-strength training increased tartrate-resistant acid phosphatase 5b concentrations (p = 0.00145). In conclusion, both training programmes were effective in the reduction of fat mass simultaneously negatively affecting bone health. However, endurance-strength training seemed to be more effective in increasing lean mass. The study protocol was registered in the ClinicalTrials.gov database under the number NCT03444207, date of registration: 23 February 2018 (retrospective registration).

A Comparative Study of Selected Gut Bacteria Abundance and Fecal pH in Bodybuilders Eating High-Protein Diet and More Sedentary Controls.

Bodybuilders tend to overeat their daily protein needs. The purpose of a high-protein diet is to support post-workout recovery and skeletal muscle growth; however, its exact impact on gut microbiota still remains under investigation. The aim of this study was to assess the differences in selected gut bacteria (Faecalibacterium prausnitzii, Akkermansia muciniphila, Bifidobacterium spp., and Bacteroides spp.) abundance and fecal pH between the group of amateur bodybuilders and more sedentary control group. In total, 26 young healthy men took part in the study, and their daily nutrients intake was measured using a dietary interview. Real-time PCR was used to assess the stool bacteria abundance. Both groups reported fiber intake within the recommended range, but bodybuilders consumed significantly more protein (33.6% ± 6.5% vs. 22% ± 6.3%) and less fat (27.6% ± 18.9% vs. 36.4% ± 10%) than controls. Study results showed no significant differences in terms of selected intestinal bacteria colony forming unit counts. Significantly higher fecal pH in the bodybuilders' fecal samples was observed in comparison to the control group 6.9 ± 0.7 vs. 6.2 ± 0.7. Gut microbiota composition similarities could be a result of appropriate fiber intake in both groups.

Type of Physical Training and Selected Aspects of Psychological Functioning of Women with Obesity: A Randomised Trial.

OBJECTIVE: We conducted a prospective randomised trial to assess whether a specific type of regular physical training performed by women with obesity is related to obtaining specific psychological benefits. METHODS: Forty-four women qualified for the study and were divided into two groups. The applied intervention consisted of regular three-month physical exercises in the form of endurance training (group A) or endurance strength training (group B). Initially, and after the completed intervention, we examined anthropometric measurements and the level of: stress (PSS-10), general self-esteem (SES), body self-report (BSQ-34, FRS), and behaviours associated with diet (TFEQ-18). RESULTS: As a result of the intervention, both groups had significantly lower anthropometric parameters and FRS scores with regard to the current figure (gr. A:δ FRS CS -0.90 ± 0.83, p < 0.001; gr. B:δ FRS CS -0.41 ± 0.50, p = 0.01) and BSQ-34 results (gr. A:δ BSQ-34 -14.90 ± 13.5, p = 0.001; gr. B:δ BSQ-34 - 18.64 ± 25.4, p = 0.01). Additionally, an increase in cognitive restraint (δ TFEQ-18 CR1.65 ± 2.06, p = 0.01) and a decrease in emotional eating (δ TFEQ-18 EE -0.82 ± 1.28, p = 0.01) were observed in group B. There were no between-group differences in terms of the magnitude of changes achieved due to the intervention, except for asignificant improvement in the perception of their current figure (FRS) (δ FRSCS -0.90 ± 0.83, p = 0.03) in group A. CONCLUSIONS: Regular physical activity over a three-month period by women with obesity promotes the perception of their own body as slimmer and lowers body shape concerns. The change in body shape perception was more pronounced under the influence of endurance training than endurance strength training. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT04793451.

Assessment of Nutrition Status in Amateur Windsurfers during Regattas in the Competitive Period-A Field Study.

Windsurfing is a demanding activity that requires a high level of physical fitness as well as appropriate training and nutritional strategies. Therefore, the aim of this study was to assess the dietary intake of amateur windsurfers and consider possible dietary mistakes. This field study was conducted among 10 Polish male amateur windsurfers (aged 22 ± 2 years, mean training experience of 9.5 ± 4 years). Dietary intake was assessed using a standardized 3-day food record. The total energy expenditure of each participant was estimated using a mobile fitness application. The daily energy supply in assessed portions of the windsurfers' food was lower than the estimated demand during the competition. The contribution of macronutrients to the total energy intake adhered to those guidelines, but not with the ones recommended for athletes practicing extreme sports. Daily fluid consumption was insufficient. In the windsurfers' diet, we noticed low consumption of vitamin D and calcium, while cholesterol, sodium, potassium, and phosphorus intake was too high. Nutritional practices of amateur windsurfers during the competitive period do not comply with current sports nutrition guidelines. The results suggest that windsurfers are in need of nutritional education and dietary counseling in order to meet macronutrient intake targets.

Endurance Training Depletes Antioxidant System but Does Not Affect Endothelial Functions in Women with Abdominal Obesity: A Randomized Trial with a Comparison to Endurance-Strength Training.

Limited data suggested that inclusion of a strength component into endurance exercises might intensify the beneficial effect of training. However, the available data is limited. Therefore, we aimed to compare the effect of endurance and endurance-strength training on anthropometric parameters, endothelial function, arterial stiffness, antioxidant status, and inflammatory markers in abdominally obese women without serious comorbidities. A total of 101 women were recruited and randomly divided into endurance (n = 52) and endurance-strength (n = 49) groups. During the three-month intervention, both groups performed supervised sixty-minute training three times a week. All studied parameters were measured pre- and post-intervention period. In total, 85 women completed the study. Both training significantly decreased anthropometric parameters. Besides, endurance training decreased endothelial nitric oxide synthase, central aortic systolic pressure, pulse wave velocity, glutathione (GSH), total antioxidant status (TAS), interleukin (IL) 8, matrix metalloproteinase (MMP) 9, and tumor necrosis factor alpha, while endurance-strength training decreased MMP-2 concentrations, and increased IL-6, monocyte chemoattractant protein-1, and MMP-9 levels. We observed significant differences between groups for GSH, TAS, and MMP-9 levels. In summary, endurance and endurance-strength training did not differ in the impact on endothelial function and arterial stiffness. However, endurance training significantly depleted the antioxidant defense, simultaneously reducing MMP-9 levels. The study was retrospectively registered with the German Clinical Trials Register within the number DRKS00019832.

Effects of an Indoor Cycling Program on Cardiometabolic Factors in Women with Obesity vs. Normal Body Weight.

The study aimed to provide evidence on the impact of indoor cycling (IC) in reducing cardiometabolic risk factors. The study compares the effects of a 3 month IC program involving three 55 min sessions per week on women aged 40-60 years, with obesity (OW, n = 18) vs. women with normal body weight (NW, n = 8). At baseline and at the end of the study, anthropometric parameters, oxygen uptake (VO2 peak), and serum parameters: glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), insulin, human anti-oxidized low-density lipoprotein antibody (OLAb), total blood antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), endothelial nitric oxide synthase (eNOS), C-reactive protein (CRP), lipid accumulation product (LAP), and homeostasis model assessment of insulin resistance index (HOMA IR) were determined. Before the intervention, VO2 peak and HDL-C levels were significantly lower and levels of TG, LAP, insulin, HOMA-IR, and CRP were significantly higher in the OW group compared to those in the NW group. After the intervention, only the OW group saw a decrease in body mass, total cholesterol, OLAb, TBARS, and CRP concentration and an increase in total body skeletal muscle mass and HDL-C concentration. In response to the IC training, measured indicators in the OW group were seen to approach the recommended values, but all between-group differences remained significant. Our results demonstrate that IC shows promise for reducing cardiometabolic risk factors, especially dyslipidemia. After 12 weeks of regular IC, the metabolic function of the OW group adapted in many aspects to be more like that of the NW group.

Effects of Endurance and Endurance-Strength Training on Endothelial Function in Women with Obesity: A Randomized Trial.

Some investigations have demonstrated that a combined endurance-strength training is the most effective in the treatment of obesity. The aim of the research was to access how different trainings influence: endothelial function, lipid metabolism, and risk of atherosclerosis in women with obesity. In a randomized trial, 39 obese women aged 28-62 completed endurance (n = 22, 60-80% HRmax) or combined training (n = 17, 20 minutes of strength exercises, 50-60% 1RM and 25 minutes of endurance training, 60-80% HRmax). Before and after the intervention vascular endothelial function (endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), thiobarbituric acid reactive substances (TBARS), blood total antioxidant capacity (TAC)), total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides and C-reactive protein (CRP)as well as visceral adiposity index (VAI), total-body skeletal muscle mass and atherogenic index of plasma (AIP) were determined. After the trainings, in both groups total cholesterol and total-body skeletal muscle mass increased (p < 0.05). In the group undergoing combined training, lower (p < 0.05) VAI, AIP, CRP and LDL-C were noted. In the group undergoing endurance training TBARS concentration decreased (p < 0.01), while the HDL-C (p < 0.01) concentration as well as eNOS (p < 0.05) activity increased. No significant differences between groups were found, either before or after the programs. Both training programs led to the improvement of lipid metabolism, but only endurance training alone favorably changed indicators of endothelial functions in women with obesity.

Influence of endurance and endurance-strength training on mineral status in women with abdominal obesity: a randomized trial.

BACKGROUND: Obesity and exercise are associated with disturbances of mineral metabolism, which can lead to physical inefficiency. Our study aimed to compare the influence of endurance and endurance-strength training on mineral status in women with abdominal obesity. METHODS: Thirty-eight abdominally obese women were randomized into groups A and B and underwent 3 months long training: group A-endurance training and group B-endurance-strength training. Anthropometric and body composition measurements were carried out and the Graded Exercise Test was performed. Blood, urine, and hair samples were collected for mineral content analysis. RESULTS: Endurance training decreased serum Fe and Zn concentrations as well as hair Zn and Cu content, and increased urine Zn concentration. Endurance-strength training increased serum Mg and Cu concentrations, decreased serum Fe and Zn concentrations, decreased hair Ca and Mg content, and increased urine Ca and Zn concentrations. After training, serum and urine Fe concentration was higher in group A, while urine Ca concentration was higher in group B. A number of correlations was found. CONCLUSIONS: Both endurance and endurance-strength training have a significant effect on mineral metabolism in obese women; the favorable effects of endurance-strength exercise predominate in iron, magnesium, zinc, and copper balance.

Skeletal Muscle Cell Damage Indicators in Volleyball Players after the Competitive Phase of the Annual Training Cycle.

The aim of the study was to evaluate the impact of the competitive phase on physiological and metabolic indices and selected markers of skeletal muscle damage in male volleyball players. The study group consisted of 24 young male volleyball players. During the study, participants underwent two series of measurements, before and after the competitive phase of the annual training cycle. In both study terms, players performed an incremental treadmill running test to determine their ventilatory threshold and maximal oxygen uptake. Venous and capillary blood samples were taken for biochemical analysis. There was no significant difference in the physical fitness level, values of biochemical variables and the level of antioxidant status in the surveyed athletes between the two study terms. Significant changes within skeletal muscle damage markers were observed between the beginning and the end of the competitive period: an increase in the concentration of cellular DNA damage products (8-hydroxy-2'-deoxyguanosine; p < 0.0001) and a decrease in muscle activity of creatine kinase (p<0.05). In spite of the increment in cell damage markers, the unaffected level of physiological and biochemical markers may indicate that the experienced cell destruction did not negatively affect the level of physical fitness. When designing the annual training plan, coaches and athletes need to take into consideration that temporary physiological states - oxidative stress and inflammation - may be required to attain training adaptation.

Influence of 12-week Nordic Walking training on biomarkers of endothelial function in healthy postmenopausal women.

BACKGROUND: The aim of this study was to evaluate the effects of a 12-week Nordic Walking (NW) intervention on nitric oxide synthase activity (eNOS), levels of antibodies against oxidatively modified low-density lipoproteins (oLAb), plasma antioxidant capacity (TAC), thiobarbituric acid reactive substance (TBARS) concentration, carbohydrate and lipid metabolism, and atherosclerosis risk factors (AIP) in postmenopausal women. METHODS: A sample of 39 women, divided into two comparable groups: training (N.=20) and control (N.=19), took part in the study. Participants in the training group performed a 12-week supervised NW training: 60-minute sessions of exercise, repeated three times per week. The biochemical and anthropometric data were obtained before and after the intervention. During the first and the last training sessions, the individual walking distance in trained group was measured. RESULTS: After the intervention, significant differences in covered distance, body mass, BMI, fat mass, insulin level (P<0.01), systolic blood pressure and TBARS concentration (P<0.05) were found in trained women. CONCLUSIONS: Applied training was able to improve functional capacity and body composition in healthy postmenopausal women. It appears to be no direct link between a significant decrease in the level of systolic blood pressure, the level of eNOS activity, TAC, oLAb and plasma TBARS concentration in trained women. It seems probable that NW training would be more effective for postmenopausal women with more severely impaired endothelial function.

Effects of Endurance and Endurance-strength Exercise on Renal Function in Abdominally Obese Women with Renal Hyperfiltration: A Prospective Randomized Trial.

OBJECTIVE: Obesity is associated with kidney defects. Physical activity is a key element in the treatment of obesity. The aim of this study was to compare the effect of endurance and endurance-strength training on kidney function in abdominally obese women. METHODS: Forty-four abdominally obese women were randomized to endurance training or endurance-strength training, three times a week for 3 months. Before and after the intervention, kidney function was assessed by measuring blood creatinine, urine creatinine, and urine albumin levels, and the albumin-to-creatinine ratio and glomerular filtration rate (GFR) were calculated. RESULTS: Renal hyperperfusion was present in both groups before the study. Following both types of physical activity, similar modifications of the investigated parameters were observed, but with no significant between-group differences. Both courses of training led to a significant increase in blood creatinine and a subsequent decrease in the GFR. A significant increase in urine creatinine and album levels, though not exceeding the range for microalbuminuria, was not accompanied by any difference in the albumin-to-creatinine ratio after endurance-strength training alone. CONCLUSION: Three months of either endurance or endurance-strength training has a favorable and comparable effect on renal function in abdominally obese women with renal hyperfiltration.

Effects of endurance and endurance-strength exercise on biochemical parameters of liver function in women with abdominal obesity.

INTRODUCTION: Obesity is a risk factor of nonalcoholic fatty liver disease. Although the standard therapy for obesity involves physical exercise, well-planned studies of the changes in liver function in response to different exercise intensities in obese subjects are scarce. The aim of the present study was to examine a question of how does exercise mode affect the liver function. MATERIAL AND METHODS: 44 women with abdominal obesity were randomized into two exercise groups: endurance (group A) and endurance-strength (group B). Women in each group exercised for 60min 3 times/week for a 3-month period. Markers of liver function: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltranspeptidase (GGT), alkaline phosphatase (ALP) activities, and bilirubin levels were quantified. RESULTS: We found significant differences in ALT (p<0.01) and AST (p<0.05) activities between group A and B after training exercise. Blood ALT and AST tended to decrease in group B, increase in group A. Significant reduction in serum GGT level after exercise in both groups was observed (p<0.001, group A; p<0.01, group B). Neither endurance nor endurance-strength exercise led to changes in serum ALP activity and total or direct bilirubin level. However, endurance-strength training resulted in significant decreases in serum indirect bilirubin (p<0.05). Strong positive correlations between serum indirect bilirubin and body mass (r=0.615; p=0.0085) and BMI (r=0.576; p=0.0154) were found after endurance-strength exercise (group B). CONCLUSION: The mode of exercise does matter: endurance-strength exercise led to a greater improvement, compared to endurance exercise, in the liver function in women with abdominal obesity.

Effects of Endurance and Endurance Strength Training on Body Composition and Physical Capacity in Women with Abdominal Obesity.

AIMS: To compare the effects of endurance training with endurance strength training on the anthropometric, body composition, physical capacity, and circulatory parameters in obese women. METHODS: 44 women with abdominal obesity were randomized into groups A and B, and asked to perform endurance (A) and endurance strength training (B) for 3 months, 3 times/week, for 60 min. Dual-energy X-ray absorptiometry and Graded Exercise Test were performed before and after training. RESULTS: Significant decreases in body mass, BMI, total body fat, total body fat mass, and waist and hip circumference were observed after both types of intervention. Marked increases in total body lean and total body fat-free mass were documented in group B. In both groups, significant increases in peak oxygen uptake, time to exhaustion, maximal work rate, and work rate at ventilatory threshold were accompanied by noticeably decreased resting heart rate, resting systolic blood pressure, and resting and exercise diastolic blood pressure. No significant differences were noticed between groups for the investigated parameters. CONCLUSION: Our findings demonstrate evidence for a favorable and comparable effect of 3-month endurance and endurance strength training on anthropometric parameters, body composition, physical capacity, and circulatory system function in women with abdominal obesity.

Bone mineral density and bone turnover in male masters athletes aged 40-64.

We evaluated areal bone mineral density (aBMD), bone mineral content (BMC), and markers of bone turnover in male competitive masters athletes representing different training profile in the past and at present, aged 40-64 (14 endurance runners, and 12 speed-power athletes), and non-sport controls (n = 13). Dual-energy X-ray absorptiometry measurements of total body and regional aBMD, BMC and soft tissue composition were acquired. Serum concentrations of osteocalcin (OC), C-terminal crosslinking telopeptide of type I collagen (CTX), tumour necrosis factor-alpha (TNF-alpha), total testosterone (TT), free testosterone (FT) and insulin like growth factor-1 (IGF-1) were measured. Adjusted total and regional aBMD and BMC (covariates: body mass, body height and age) were significantly greater in all measured regions in speed-power athletes than in endurance athletes and control subjects, but adjusted aBMD and BMC values were not significantly different between endurance athletes and controls. No differences in bone formation (OC), bone resorption (CTX), and serum concentrations of TNF-alpha, TT, FT and IGF-1 were noted. This suggests that weight-bearing exercise in young age and the training continuation in later life may be an important contributor to the aBMD and BMC in the middle age and in the elderly. It seems also that training-related bone differences in men are not caused by present alterations in bone turn-over or somatotropic effects. However, conclusions must be drawn with caution due to a large variability of biochemical markers.

Response of oxidative stress markers and antioxidant parameters to an 8-week aerobic physical activity program in healthy, postmenopausal women.

The aim of the study was to assess the influence of an 8-week aerobic physical activity program on oxidative stress markers, antioxidant parameters, and selected metabolic parameters in healthy, postmenopausal women. The study was carried out in a group of 41 healthy women (mean age 65 years) participating in an 8-week cycle ergometer physical workout of moderate intensity. Before and after completing the training program, the following parameters were assessed: total antioxidant status (TAS) and concentrations of thiobarbituric acid reactive substances (TBARS) in plasma, serum levels of antibodies against oxidatively modified low-density lipoproteins (LDL) (oLAB), serum concentrations of glucose, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), insulin, and reduced glutathione (GSH) concentrations in red blood cells (RBC). Atherogenic index of plasma (AIP) and insulin resistance index (HOMA(IR)) were calculated. The 8-week aerobic physical activity program resulted in significant decrease (p<0.01) in serum glucose and LDL-cholesterol (LDL-C) levels, plasma TBARS concentrations (p<0.05), and in significant decrease of HOMA(IR) (p<0.01). TAS of plasma and GSH concentrations in RBC increased significantly (p<0.01) over the study period. The results show that an 8-week aerobic training enhanced insulin sensitivity, and improved the balance between oxidants and antioxidants in healthy, postmenopausal women.

Insulin resistance, oxidative stress markers and the blood antioxidant system in overweight elderly men.

The purpose of the study was to examine in the blood of overweight men aged from 62 to 83 years, the relationships between age and insulin resistance, selected parameters of the oxidative stress, and the antioxidant defense system. The population studied was divided into two groups: the group 'young-old' consisted of men aged 62 to 74 years old, and the group 'old-old'--of men aged between 75 and 83 years. The total antioxidative status (TAS) and concentrations of thiobarbituric acid reactive substances (TBARS) were measured in the blood plasma. In the serum samples, the levels of antibodies against oxidized LDL (oLAB), glucose, total cholesterol, HDL-cholesterol, triglycerides and insulin were measured. Homeostasis Model Assessment of Insulin Resistance (HOMAIR) was calculated. Concentration of reduced glutathione (GSH) and glutathione peroxidase activity (GPx) were determined in the red blood cells hemolysate. The results of the study did not show significant differences between groups investigated with respect to concentrations of TBARS, TAS, GSH and GPx. However, significantly higher concentrations of glucose and antibodies against oxLDL (p < 0.05) were observed in the group of men over 74 years old in comparison to the group of 'young-old' men. It was indicated that the increased insulin resistance and hyperglycemia in elderly men are related to body mass and that they cause intensified oxidative modifications of LDL.