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This study aimed to compare the effects of 1×1 small-sided games (SSGs) with different bout durations on external (ETL) and internal training loads (ITL) in youth soccer players. Twenty U18 players were divided into two groups performing six 1×1 SSGs with 30 and 45 s bout durations. ITL indices, including the percentage of maximum heart rate (HR), blood lactate (BLa) level, pH, bicarbonate (HCO3¯) level, and base excess (BE) level, were measured at rest, after each SSG bout, and 15 and 30 min after the entire exercise protocol. ETL (Global Positioning System metrics) was recorded during all six SSG bouts. The analysis showed that the 45 s SSGs had a greater volume but a lower training intensity than the 30 s SSGs. A significant time effect was observed in all ITL indices and a significant group effect in the HCO3¯ level only. Finally, the changes in the HR and HCO3¯ level were smaller in the 45 s SSGs than in the 30 s SSGs. In conclusion, the HR and BLa level during short-bout SSG training have limited diagnostic value for ITL. Extending ITL monitoring using other indicators, such as the HCO3¯ and BE levels, appears reasonable.

The aim of the study was to determine the effects of a 6-month training cycle on muscle damage and inflammatory markers in youth male soccer players. Twenty-one soccer players were tested four times: at the beginning (T1) and immediately after the pre-season period (T2), in the middle (T3) and at the end of the competitive period (T4). Muscle damage and inflammatory markers were determined in blood taken 36 hours after the match. Throughout the training cycle significant increases (p < 0.05) of creatine kinase (T1: 254.4 U·L-1; T4: 304.2 U·L-1) and lactate dehydrogenase (T1: 382.8 U·L-1; T4: 453.2 U·L-1) activities were observed. Significant changes (p < 0.05) in platelet count (T1: 210.5·109·L-1; T4: 234.2·109·L-1), percentage of lymphocyte (T1: 39.80%; T4: 42.97%), monocyte (T1: 6.88%; T4: 9.99%) and granulocyte (T1: 53.32%; T4: 47.05%) as well as in granulocyte-to-lymphocyte (T1: 1.41; T4: 1.17) and lymphocyte-to-monocyte (T1: 6.21; T4: 4.46) ratios were noted. The correlation analysis revealed statistically significant relationships (p < 0.05) between: myoglobin and the percentage of leukocyte subpopulations and the granulocyte to lymphocyte ratio; lactate dehydrogenase and the percentage of monocyte; lactate and leukocyte count. In conclusion, the reported muscle damage and inflammatory markers in T3 and T4 indicate the need for fatigue status monitoring in youth soccer players, especially in the competitive period. Moreover granulocyte to lymphocyte and lymphocyte to monocyte ratios proved to be sensitive to fatigue changes and therefore can provide coaches and sport scientists with a broader perspective on the biochemical monitoring of training status in soccer players.

The aim of the research was to present the importance of measuring the impulse of force in assessing exercise capacity in professional rowers and canoeists rather than conducting traditional physiological and biochemical analyses. A group of 20 athletes (12 rowers and 8 canoeists) underwent progressive intensity exercise tests in two testing sessions (before and after a training period). During the tests, maximal aerobic capacity, impulse of strength, metabolic indices, and markers of skeletal muscle damage were assessed. Total testosterone, free testosterone, cortisol, interleukin 1,6, and creatine kinase were evaluated in venous blood. The impulse of force at the ventilatory threshold and at the maximum load was correlated with free testosterone and a total testosterone/cortisol ratio during exercise (p ≤ 0.05) and was negatively correlated with cortisol concentration (p ≤ 0.05) in the first testing session (before training intervention). Values were positively correlated with concentration of total testosterone, free testosterone and total testosterone/cortisol, and free testosterone/cortisol ratios during exercise (p ≤ 0.05) in the second testing session (after training intervention). Biochemical indices of overtraining were correlated with maximum oxygen uptake in each session and with the impulse of force at the ventilatory threshold and the maximum load of exercise. Thus, there is an indirect relationship between maximal aerobic capacity and the impulse of force. The measurement of the impulse of force can become a simple and effective method for evaluating the overall exercise capacity of rowers because of its relationship with indices of the load and changes in hormonal indices of anabolic and catabolic processes during exercise. Therefore, it may constitute a replacement for the traditional laboratory measurement of VO2max in highly qualified rowers and canoeists.

The aim of the work was to assess the intensity of purine nucleotide degradation during maximum physical exercise. 5 elite female boxers were the subject of the study. Each of them underwent two exercise stress tests in order to evaluate the level of V̊O2peak and the level of anaerobic capacity during a Wingate test. The study involved collecting capillary and venous blood samples at rest and after the exercise test to determine the Acid-Base Balance (ABB), concentration of lactic acid (LA) and purine metabolism nucleotides. The average value of V̊O2peak was 40.92 (SD = 4.087) ml/kg/min, the average anaerobic capacity Ppeak was 7.57 (SD = 0.380) Watt/kg. The workload resulted in significant changes in the level of ABB and LA after both of the exercise stress tests (p < 0.001). Concentrations of hypoxanthine (Hx), xanthine (X) and uric acid (UA) in the blood increased significantly after the Wingate test (p < 0.05). The level of plasma purine nucleotides at rest and after standard exercise may be a useful tool for monitoring the adaptation of energetic processes in different training phases and support the overload diagnosis.

The optimal type of exercise that simultaneously decreases body weight and preserves bone health in people with obesity is unknown. This parallel randomized trial aimed to compare the effect of endurance and endurance-strength training on bone mineral density (BMD) and content (BMC) in abdominally obese postmenopausal women. A total of 101 women were recruited and randomly assigned to endurance or endurance-strength training groups. Participants trained for 60 min per day, three times per week for 12 weeks. The endurance exercises were performed at an intensity of 50–75% of the maximum heart rate, whereas the strength exercises were at 50–60% of the one-repetition maximum. Pre- and post-intervention BMD and BMC of the total body, lumbar spine, and femoral neck and physical capacity were measured. There were no differences among the densitometric parameters in the endurance group, but a significant increase in whole-body BMD in the endurance-strength group was found. Moreover, there was a significant difference between the groups in the changes in the lumbar spine BMC. Furthermore, both training programs significantly improved physical capacity with no differences between groups. Endurance training was more effective in maintaining BMC at the lumbar spine. However, both groups did not differ in effect on BMD. Further studies with a long-term follow-up should be considered to confirm these findings. The study was registered with the German Clinical Trials Register within the number DRKS00019832, and the date of registration was 26 February 2020 (retrospective registration).

The objective of this study was to assess the effect of 8-week long endurance training on the prooxidative–antioxidative status of plasma in women treated for breast cancer. The participants of the study were 12 women after radical mastectomy aged 45 to 56 years (M = 50.6 ± 2.9 years), who had undergone full cancer treatment, on average more than 5 years after the treatment (M = 5.9 ± 0.9 years). Body mass components were measured twice using the method of bioelectric impedance analysis. In order to optimize training loads and to assess the level of exercise tolerance of the participants, the group was subject to an ergospirometric exercise test twice, before (1st) and after (2nd) the completion of the training cycle. The blood was also taken twice for biochemical analyses. Statistically significant differences were noted in the maximum exercise load, the level of which increased in the second test (p &lt, 0.05). No change was observed in the level of antioxidative potential, i.e., the content of some variables, ferric reducing ability of plasma (FRAP), urea, total phenolics, thiobarbituric acid reactive substances (TBARS), and in the blood indices of the body’s nutritional status during the project (total protein, albumin. Endurance training caused an increase in exercise tolerance and did not cause an aggravation of oxidative stress in women undergoing breast cancer treatment.

Long-term insulin treatment can slow the growth process and decrease physical fitness level in children. In diabetic children, these two developments should be constantly monitored. The aim of the present study was to examine differences in somatic and physical fitness characteristics between soccer-training boys with type 1 diabetes and healthy boys of the same age (reference values based on Polish population norms for somatic and motor parameters). The participants were 94 boys (8–17 years), diagnosed with diabetes, who participated in soccer training on a regular basis and received routine medical care. The study involved (a) anthropometric and body composition measurements, (b) general motor ability assessments, and (c) comparison of those characteristics with the healthy Polish population. The diabetic boys were found to have lower levels of almost all somatic traits and motor abilities as compared with the healthy boys (p ≤ 0.05). Handgrip strength was a variable with the smallest difference between the two groups. The observed differences indicate the necessity to design an appropriate control and assessment system based on simple medical and fitness field tests for diabetic children and adolescents. It will allow optimizing advanced training as well as minimize health risks before, during, or after exercise.

This study assesses the status of hydration and the acid-base balance in female handball players in the Polish Second League before and after simulated matches in both indoor (hall) and beach (outdoor) conditions. The values of biochemical indicators useful for describing water-electrolyte management, such as osmolality, hematocrit, aldosterone, sodium, potassium, calcium, chloride and magnesium, were determined in the players&rsquo, fingertip capillary blood. Furthermore, the blood parameters of the acid-base balance were analysed, including pH, standard base excess, lactate and bicarbonate ion concentration. Additionally, the pH and specific gravity of the players&rsquo, urine were determined. The level of significance was set at p &lt, 0.05. It was found that both indoor and beach simulated matches caused post-exercise changes in the biochemical profiles of the players&rsquo, blood and urine in terms of water-electrolyte and acid-base balance. Interestingly, the location of a simulated match (indoors vs. beach) had a statistically significant effect on only two of the parameters measured post-exercise: concentration of calcium ions (lower indoors) and urine pH (lower on the beach). A single simulated game, regardless of its location, directly affected the acid-base balance and, to a smaller extent, the water-electrolyte balance, depending mostly on the time spent physically active during the match.

This study sought to evaluate the hormonal response (i.e. total testosterone, free testosterone, cortisol, and their ratios TT/C and FT/C) in the under-19 youth soccer team (n = 18) throughout a six-month period. All sport medical examinations were conducted four times: before the beginning of the preparation period (T1), just after preparation period (T2), in the middle of the competitive period (T3), and at the end of the season (T4). The cortisol concentration was decreased at the T3 (-16.9%; p = 0.014), then increased at the T2 (16.8%; p = 0.001) and at the T4 (12.7%; p = 0.062), respectively, compared to the initial value. The analyses for total and free testosterone demonstrated no differences between the measurements. Finally, values of the TT/C and FT/C ratios were increased during the T3 (25%; p = 0.017, 24.4%; p = 0.021) in comparison with the initial measurement and decreased at the T4 (-28.9%; p = 0.001, - 30.8%; p = 0.001) in comparison with the T3. The study results showed that the lowest level of peripheral fatigue was recorded in the T3, which may suggest that a correct selection of training loads does not affect the severity of catabolic processes in youth players.

The purpose of this study was to assess the effect of Nordic walking training on the indices of bone and carbohydrate metabolism in relation to 25(OH)D levels in postmenopausal women that were subjected to the outdoor systematic physical activity. The study was performed in 10 postmenopausal women, who participated in a 12-week Nordic walking exercise program, taking place during spring months (March to June). Anthropometric and biochemical parameters were measured before and after the training program. Serum concentrations of 25-hydroksycholekalciferol (25(OH)D), parathyroid hormone (PTH), insulin, glucose, osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), and calcium were determined. After the Nordic walking exercise program, a significant increase in the serum levels of 25(OH)D and CTX and a decrease in body mass, body mass index (BMI), fat mass, and PTH concentrations were observed. The findings of the present study suggest that 25(OH)D, as important metabolic regulator, plays a role in the modification of bone markers&rsquo, responses after the outdoor training program, independent of the physical activity effects.

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

This study aimed at investigating the effects of 2, 4 and 8 weeks of endurance training on the contractile properties of slow (S), fast fatigue resistant (FR) and fast fatigable (FF) motor units (MUs) in rat medial gastrocnemius (MG) in relation to the changes in muscle mitochondrial biogenesis. The properties of functionally isolated MUs were examined in vivo. Mitochondrial biogenesis was judged based on the changes in mitochondrial DNA copy number (mtDNA), the content of the electron transport chain (ETC) proteins and PGC-1α in the MG. Moreover, the markers of mitochondria remodeling mitofusins (Mfn1, Mfn2) and dynamin-like protein (Opa1) were studied using qPCR. A proportion of FR MUs increased from 37.9% to 50.8% and a proportion of FF units decreased from 44.7% to 26.6% after 8 weeks of training. The increased fatigue resistance, shortened twitch duration, and increased ability to potentiate force were found as early as after 2 weeks of endurance training, predominantly in FR MUs. Moreover, just after 2 weeks of the training an enhancement of the mitochondrial network remodeling was present as judged by an increase in expression of Mfn1, Opa1 and an increase in PGC-1α in the slow part of MG. Interestingly, no signs of intensification of mitochondrial biogenesis assessed by ETC proteins content and mtDNA in slow and fast parts of gastrocnemius were found at this stage of the training. Nevertheless, after 8 weeks of training an increase in the ETC protein content was observed, but mainly in the slow part of gastrocnemius. Concluding, the functional changes in MUs' contractile properties leading to the enhancement of muscle performance accompanied by an activation of signalling that controls the muscle mitochondrial network reorganisation and mitochondrial biogenesis belong to an early muscle adaptive responses that precede an increase in mitochondrial ETC protein content.

Post-physical training changes in iron metabolism in the human body often occur. To fully describe these processes, fifteen male Polish National Team field hockey players (age 27.7 ± 5.2 years, body mass 72.8 ± 7.6 kg and body height 177.1 ± 5.7 cm) were examined in three phases of an annual training cycle: preparatory (T1), competitive (T2) and transition (T3). To assess aerobic fitness, maximal oxygen uptake (VO2max) was evaluated. Based on the iron concentration, the changes in total iron binding capacity (TIBC), unsaturated iron binding capacity (UIBC) and other selected haematological indicators (haemoglobin, erythrocytes, mean corpuscular haemoglobin - MCH) in iron metabolism were estimated. The average values of maximum oxygen uptake increased from 54.97 ± 3.62 ml·kg−1·min−1 in T1 to 59.93 ± 3.55 ml·kg−1·min−1 in T2 (p−1·min−1 in T3 (p

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.

The search for genes with a positive influence on physical fitness is a difficult process. Physical fitness is a trait determined by multiple genes, and its genetic basis is then modified by numerous environmental factors. The present study examines the effects of the polymorphism of creatine kinase (CKM) gene on VO2max - a physiological index of aerobic capacity of high heritability. The study sample consisted of 154 men and 85 women, who were students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. The study revealed a positive effect of a rare G (NcoI-) allele of the CKM gene on maximal oxygen uptake in Caucasian women practicing sports requiring aerobic and anaerobic exercise metabolism. Also a tendency was noted in individuals with NcoI-/- (GG) and NcoI-/+ (GA) genotypes to reach higher VO2max levels.

In this study the R577X polymorphism of the α-actinin-3 (ACTN3) gene was analysed in relation to physical fitness measured with maximal oxygen uptake (VO2max). The studies were carried out in a group of 154 men and 85 women, students of the University of Physical Education in Poznań and professional athletes representing various sports and fitness levels. In our research physiological and molecular procedures were used, i.e. direct measurement of maximum oxygen uptake (VO2max) and R577X a-ACTN3 genotyping by PCR-RFLP. The results do not confirm some literature data concerning a statistically significant association of R577X polymorphism in the ACTN3 gene and the level of maximal oxygen uptake (VO2max). A trend was observed for higher VO2max values to be found in individuals with the XX and RX genotypes as well as the predominance of the RR genotype in the group of individuals practising speed and power disciplines.

The influence of short-term high altitude training on inflammatory and prooxidative-antioxidative indices in alpine ski athletes Exposure of alpine skiing athletes, while training, at altitude hypoxia and low ambient temperature can modify the response of the immune system and increase reactive oxygen and nitrogen species (RONS) generation. The aim of this study was to evaluate the impact of six day training model "live low - train high" on selected indicators of immune and antioxidant-prooxidant balance of alpine skiing competitors. The study was performed in 7 men, alpine skiers, who underwent 6-day training at Kaunertal glacier (3160 m). Before departure to glacier training, and after returning to sea level participants underwent series of tests. Somatic characteristics, anaerobic exercise capacity, blood morphological parameters and concentrations of interleukin 6 (IL-6), C-reactive protein (hsCRP), thyroid stimulating hormone (TSH), thiobarbituric acid reactive substances (TBARS), total antioxidant status (TAS), total iron (Fe) and total iron binding capacity (TIBC) were assessed. High altitude training has led to a significant increase in anaerobic capacity (p

AB Purpose: This cross-sectional study compared the oxygen uptake at the gas exchange threshold (GET) and its relation to age between highly trained competitive speed-power athletes (SP), endurance athletes, and untrained participants. Methods: A total of 199 men ages 20-90 yr were examined: 51 SP, 87 endurance runners (ER), and 61 untrained individuals (UT). Physiological parameters at GET were obtained during a graded treadmill test until exhaustion: oxygen uptake (V[spacing dot above]O2GET), HRGET, and oxygen pulse (O2 PulseGET). Information about training history and volume was collected. A linear model of regression was adopted. Results: Average V[spacing dot above]O2GET was lower in the SP than that in ER group but significantly higher in the SP than that in UT group across the whole age range. Absolute rate of decline in V[spacing dot above]O2GET was smaller in the SP than ER group and smallest in the UT group (0.38, 0.56, and 0.22 mL[middle dot]kg-1[middle dot]min-1[middle dot]yr-1, respectively). Percentage decline per decade did not differ between groups (7.9%-8.7%). Above the age of 50 yr, absolute and percentage rates of decline were considerably lower in the SP than ER group (0.24 vs 0.65 mL[middle dot]kg-1[middle dot]min-1[middle dot]yr-1 and 7.2% vs 13.4% per decade, respectively). About the age of 85, the predicted level of V[spacing dot above]O2GET in the SP group was close to that of the ER group. The training volume correlated significantly with V[spacing dot above]O2GET in athletes (r = 0.67-0.70). Main predictors of O2GET were V[spacing dot above]O2 PulseGET and HRGET (89.9%-95.6% and 4.1%-9.8% of explained variance, respectively). Conclusions: Our results suggest that the "speed-power model" of lifelong physical activity is associated with an elevated level of V[spacing dot above]O2GET and its relatively slow age-related decline

Purpose. Genetic factors play an important role in physical performance. In this study, the polymorphism of the angiotensinconverting enzyme gene (ACE) was analyzed in relation to the level of physical fitness, measured by maximal oxygen uptake (VO2max). Methods. Molecular genetic research on the ACE gene was carried out on a group of 154 men and 85 women. All of the subjects were Polish students at the University School of Physical Education in Poznan and included professional athletes representing various sport disciplines and levels of fitness. Results. Allele I was found to have an advantageous effect on higher maximal oxygen uptake values and, in addition, a characteristic distribution of genotypes was found, where allele II was more common in individuals practicing aerobic sports and allele DD in individuals training anaerobic disciplines. Conclusion. No significant associations were found between I/D polymorphism in the ACE gene and VO2max values but certain tendencies were found for those individuals with the ACE II genotype.

Physical fitness is a trait determined by multiple genes, and its genetic basis is modified by numerous environmental factors. The present study examines the effects of the (CA)n tandem repeats polymorphism in IGFI gene and SNP Alw21I restriction site -202 A>C polymorphism in IGF1BP3 on VO2max--a physiological index of aerobic capacity of high heritability. The study sample consisted of 239 (154 male and 85 female) students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. An association was found between -202 A/C polymorphism of IGFBP3 gene with VO2max in men. Higher VO2max values were attained by men with CC genotype, especially male athletes practicing endurance sports and sports featuring energy metabolism of aerobic/anaerobic character. A statistically significant influence of allele 188 and genotype 188/188 of tandem repeats (CA)n polymorphism of IGF1 gene on VO2max was found in women. Also, lower values of maximal oxygen uptake were noted in individuals with allele 186 or genotype 186/186, and higher VO2max values in athletes with allele 194.