Hematological and Biochemical Parameters in Elite Soccer Players During A Competitive Half Season

Elucidating Iron Metabolism through Molecular Imaging

Iron is essential for many physiological processes, and the dysregulation of its metabolism is implicated in the pathogenesis of various diseases. Recent advances in iron metabolism research have revealed multiple complex pathways critical for maintaining iron homeostasis. Molecular imaging, an interdisciplinary imaging technique, has shown considerable promise in advancing research on iron metabolism. Here, we comprehensively review the multifaceted roles of iron at the cellular and systemic levels (along with the complex regulatory mechanisms of iron metabolism), elucidate appropriate imaging methods, and summarize their utility and fundamental principles in diagnosing and treating diseases related to iron metabolism. Utilizing molecular imaging technology to deeply understand the complexities of iron metabolism and its critical role in physiological and pathological processes offers new possibilities for early disease diagnosis, treatment monitoring, and the development of novel therapies. Despite technological limitations and the need to ensure the biological relevance and clinical applicability of imaging results, molecular imaging technology's potential to reveal the iron metabolic process is unparalleled, providing new insights into the link between iron metabolism abnormalities and various diseases.

Medical Checks for Professional Football Players in Franceville, Gabon

THE AIM OF THE STUDY

To describe the clinical and non-clinical characteristics of Gabon footballers in the Haut-Ogooue Polyclinic in Franceville, Gabon, during visits, to assess whether they are not contraceptive to sports.

PATIENTS AND METHODS

A descriptive and analytical cross-sectional study was conducted in the city of Franceville, Gabon, in May 2022. The first and second divisions of footballers were subjected to medical examinations to determine whether they had any contraindications for playing sports, including clinical examinations, rest electrocardiograms (ECG), rest cardiac ultrasounds, chest X-rays, Rick-Dickson and biological checks.

RESULTS

The average age of 88 footballers (22-25 years) was 23 years. Blood pressure (BP) is abnormal in 19% of players, and alcohol and tobacco consumption is reported in 70% and 30%, respectively. Exercise adaptation was also closely associated with age (P = 0.00137724; P = 0.008974301), football position (P = 0.009957548; P = 0.006646182) and alcohol consumption (P = 0.000531971). Electrical and biological changes were 16% and 86.79%, respectively. Sinus bradycardia and first-degree atrioventricular block are the most common ECG abnormalities. Metabolic, inflammatory, infectious, electrolyte and anaemia syndromes were found in 22.64%, 24.53%, 19.81%, 7.55% and 12.26%, respectively. Midfielders and defenders have shown the greatest changes in biological parameters.

CONCLUSION

Medical checks are essential to determine if sports are contraindicated, as they can help identify physiological and pathological conditions and improve the monitoring of athletes.

Oxidative status alteration during aerobic-dominant mixed and anaerobic-dominant mixed effort in judokas

This study aimed to depict the oxidative status variation in judokas during aerobic-dominant mixed effort (AeDME) and anaerobic-dominant mixed effort (AnDME). It is to be expected that the sporting commitment of Judo is a stimulus of oxidative stress leading to the recruitment of antioxidant responses. Blood samples were collected from 17 athletes at rest, immediately after a training session (AeDME) and after a 5-min bout (AnDME). AeDME and AnDME caused significant increases in malondialdehyde (MDA) (p < 0.01 and p < 0.001 respectively) and glutathione (GSH) (p = 0.018 and p < 0.001 respectively). Blood thiol concentrations decreased following AeDME and AnDME (p < 0.001) whilst catalase decreased significantly after AnDME (p = 0.026) only. Uric acid increased significantly after AnDME than after AeDME (p = 0.047) while, conversely, total bilirubin was higher after AnDME than after AeDME (p = 0.02). We may ultimately summarize that AeDME and AnDME caused oxidative stress, higher in AnDME, and some antioxidant response slightly higher in AnDME compared to AeDME. In sports, monitoring of oxidative stress status is recommended as part of the training regimen.

Changes in Hematological Parameters of Iron Status and Total Iron Concentrations in Different Biological Matrices during a Sports Season in Women's Soccer Players

Iron (Fe) metabolism and concentrations change during a sports season. Fe deficiency affects a significant number of women athletes. The aims of the present study were: (i) to analyze changes in hematological parameters of Fe status and (ii) to analyze changes in Fe concentrations in different biological matrices (serum, plasma, urine, erythrocytes, and platelets) during a sports season. Twenty-four Spanish semi-professional women's soccer players (23.37 ± 3.95 years) participated in the present study. Three assessments were performed throughout the sports season (beginning, middle and end of the season). Nutritional intake was evaluated and female hormones, hematological parameters of Fe status and Fe concentrations in plasma, serum, urine, erythrocytes and platelets were determined. There were no differences in Fe intake. Hemoglobin and mean corpuscular hemoglobin concentrations increased at the end of the season compared to initial values (p < 0.05). There were no significant changes in extracellular Fe concentrations (plasma, serum, and urine). However, erythrocyte Fe concentrations were lower at the end of the season (p < 0.05). Hematological parameters of Fe status and intracellular Fe concentrations change throughout the sports season in women's soccer players.

Sex differences in cadmium and lead concentrations in different biological matrices in athletes. Relationship with iron status

PURPOSE

The present study aimed to analyse sex differences in cadmium and lead concentrations in plasma, urine, platelets and erythrocytes and to relate these concentrations to biomarkers of iron status.

METHODS

A total of 138 soccer players divided according to sex: men (n = 68) and women (n = 70) participated in the present study. All participants resided in the city of Cáceres (Spain). Erythrocyte, haemoglobin, platelet, plateletcrit, ferritin and serum iron values were determined. Cadmium and lead concentrations were quantified by inductively coupled plasma mass spectrometry.

RESULTS

The women had lower haemoglobin, erythrocyte, ferritin and serum iron values (p < 0.01). Regarding cadmium, the women showed higher concentrations in plasma, erythrocytes and platelets (p < 0.05). As for lead, they also showed higher concentrations in plasma, relative values of erythrocytes and relative values of platelets (p < 0.05). Significant correlations were observed between cadmium and lead concentrations with biomarkers of iron status.

CONCLUSIONS

Cadmium and lead concentrations are different between sexes. Biological differences between sexes and iron status could influence cadmium and lead concentrations. Lower serum iron concentrations and markers of Fe status increase Cd and Pb concentrations. Ferritin and serum iron have been directly related to increased Cd and Pb excretion.

Body Composition and Nutritional Status of the Spanish National Breaking Team Aspiring to the Paris 2024 Olympic Games

Breaking is a sports dance modality that will debut for the first time at the Paris 2024 Olympic Games. This dance form combines street dance steps with acrobatics and athletic elements. It complies with gender equality, maintains aesthetic appeal, and is practised indoors. The objective of this study is to assess the characteristics of body composition and nutritional status of the athletes that make up the Breaking national team. This national team was recruited, and they underwent an analysis of body composition using bioimpedance measurement and a nutritional interview status with the completion of a survey on the frequency of the consumption of sports supplements and ergogenic aids. In addition, they completed a consumption questionnaire for a series of food groups with specified protein, lipid, and carbohydrate content. After that, parameters were analyzed in relation to their nutritional status during a complete medical examination at the Endocrinology and Nutrition Service of the Sports Medicine Center of CSD. A descriptive analysis of the results obtained was carried out to find the mean values of the variables analyzed. The analytical parameters described an adequate nutritional status, except for the mean capillary determination of 25-OH-vitamin D3, which was 24.2 ng/dL (SD: 10.3). Bone mineral density values were higher than those of the general population. This is the first time that a study of these characteristics has been carried out on Breakers, so it is highly relevant to increase knowledge in this area in order to conduct nutritional interventions aimed at improving the sports performance of these athletes.

Cutting edge concepts: Does bilirubin enhance exercise performance?

Exercise performance is dependent on many factors, such as muscular strength and endurance, cardiovascular capacity, liver health, and metabolic flexibility. Recent studies show that plasma levels of bilirubin, which has classically been viewed as a liver dysfunction biomarker, are elevated by exercise training and that elite athletes may have significantly higher levels. Other studies have shown higher plasma bilirubin levels in athletes and active individuals compared to general, sedentary populations. The reason for these adaptions is unclear, but it could be related to bilirubin's antioxidant properties in response to a large number of reactive oxygen species (ROS) that originates from mitochondria during exercise. However, the mechanisms of these are unknown. Current research has re-defined bilirubin as a metabolic hormone that interacts with nuclear receptors to drive gene transcription, which reduces body weight. Bilirubin has been shown to reduce adiposity and improve the cardiovascular system, which might be related to the adaption of bilirubin increasing during exercise. No studies have directly tested if elevating bilirubin levels can influence athletic performance. However, based on the mechanisms proposed in the present review, this seems plausible and an area to consider for future studies. Here, we discuss the importance of bilirubin and exercise and how the combination might improve metabolic health outcomes and possibly athletic performance.

Biomarkers of post-match recovery in semi-professional and professional football (soccer)

High-level football (soccer) players face intense physical demands that result in acute and residual fatigue, impairing their physical performance in subsequent matches. Further, top-class players are frequently exposed to match-congested periods where sufficient recovery times are not achievable. To evaluate training and recovery strategies, the monitoring of players' recovery profiles is crucial. Along with performance and neuro-mechanical impairments, match-induced fatigue causes metabolic disturbances denoted by changes in chemical analytes that can be quantified in different body fluids such as blood, saliva, and urine, thus acting as biomarkers. The monitoring of these molecules might supplement performance, neuromuscular and cognitive measurements to guide coaches and trainers during the recovery period. The present narrative review aims to comprehensively review the scientific literature on biomarkers of post-match recovery in semi-professional and professional football players as well as provide an outlook on the role that metabolomic studies might play in this field of research. Overall, no single gold-standard biomarker of match-induced fatigue exists, and a range of metabolites are available to assess different aspects of post-match recovery. The use of biomarker panels might be suitable to simultaneously monitoring these broad physiological processes, yet further research on fluctuations of different analytes throughout post-match recovery is warranted. Although important efforts have been made to address the high interindividual heterogeneity of available markers, limitations inherent to these markers might compromise the information they provide to guide recovery protocols. Further research on metabolomics might benefit from evaluating the long-term recovery period from a high-level football match to shed light upon new biomarkers of post-match recovery.

Total Iron Concentrations in Different Biological Matrices-Influence of Physical Training

Iron (Fe) is one of the most widely studied trace mineral elements. Fe metabolism and homeostasis could be altered by physical training. The aim of this study was to analyze the influence of long-term physical training on serum, plasma, urine (extracellular), erythrocyte and platelet (intracellular) Fe concentrations. Forty men from the same geographical area divided into a training group (TG; n = 20; 18.15 ± 0.27 years) and a control group (CG; n = 20; 19.25 ± 0.39 years) participated in this study. The TG was composed of soccer players of the highest youth category. The CG consisted of young people who did not follow any training routine and had not practiced any sport for at least the previous six months. The TG showed higher plasma and serum Fe concentrations (p < 0.05), but lower concentrations in erythrocytes and platelets compared to the CG (p < 0.01). Due to the differences observed in the extracellular and intracellular compartments, it seems necessary to perform a global Fe analysis to assess Fe status.

Effects of different training intensities in high-intensity interval training (HIIT) on maximal aerobic velocity, hematological and muscle-damage markers in healthy young adults

This study aimed to examine the effects of two high-intensity interval training programs (HIIT) on maximal aerobic velocity (MAV), hematological variations and muscle damage markers in young healthy adults. Twenty-nine male physical education students, aged 20.3 ± 3.3 years, volunteered to participate in this study, and were randomly assigned to a control group (CG, n = 9) or two intervention groups (group 1 or 2). Intervention group 1 (n = 10) exercised at 100% of their MAV (EG₁₀₀) while group 2 (n = 10) exercised at 110% MAV (EG₁₁₀). Before and after the eight week training program, blood samples were drawn at rest, before, and after an intermittent exercise. Aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), C reactive protein (CRP), creatine kinase (CK) concentrations and hematological parameters (white blood cells [WBC], monocytes [MO], lymphocytes [LY], neutrophil [NE]) and lactate dehydrogenase (LDH) were measured. Post-hoc tests showed that MAV was significantly higher in EG₁₁₀ compared to EG₁₀₀ after HIIT (p < 0.01, η_p² = 0.05), whilst ALAT, ASAT, and CPR were significantly lower (p < 0.01; 0.02 < η_p² < 0.11) in EG₁₁₀ compared to EG₁₀₀. Moreover, post-hoc tests indicated that LY decreased significantly (p < 0.001, η_p² = 0.21) only for EG₁₁₀. Furthermore, there were significant positive correlations for both EG₁₀₀ and EG₁₁₀ between MAV and ALAT (r = 0.66, p = 0.044 and r = 0.64, p = 0.041 respectively), CK (r = 0.67, p = 0.031 and r = 0.86, p = 0.030, respectively), LDH (r = 0.74, p = 0.014, and r = 0.071, p = 0.021, respectively). In addition, there was a significant positive correlation for both, EG₁₀₀ and EG₁₁₀ between MAV and LY (r = 0.79, p < 0.01; r = 0.72, p < 0.05, respectively). Concerning the relationship between MAV and NE, there was a significant positive correlation (r = 0.66; p < 0.05) only for EG₁₁₀. Findings from this study revealed that HIIT at 110% MAV was more efficient to improve MAV and reduce muscle damage. In addition, we observed significant associations between performance improvements (MAV) and markers of muscle damage.

Serum Bilirubin Concentrations and the Prevalence of Gilbert Syndrome in Elite Athletes

Objectives

Bilirubin is a potent endogenous antioxidant and immunomodulating substance, which is also implicated in both cell signalling and various metabolic pathways. Mild elevation of systemic bilirubin concentrations provides substantial protection against many diseases of civilization. Rare published reports have suggested that serum bilirubin might also be relevant to sports performance. The purpose of the current study was to evaluate serum bilirubin concentrations and the prevalence of Gilbert syndrome (GS) in elite athletes.

Methods

The study was carried out in 536 consecutive healthy elite athletes and in 2594 individuals of the Czech post-MONICA study representing the general Czech population. Serum bilirubin concentrations, the prevalence of benign hyperbilirubinemia > 17 µmol/L (1 mg/dL, a phenotypic sign of GS), and a variant of the UGT1A1 gene promoter responsible for GS manifestation in Caucasians (rs81753472) were evaluated in study subjects.

Results

Compared to the general Czech population, significantly higher serum bilirubin concentrations were found in elite athletes (9.6 vs. 11.6 µmol/L, p < 0.001), both in men (11.3 vs. 12.6 µmol/L, p < 0.001) and women (8.3 vs. 10.5 µmol/L, p < 0.001). Furthermore, the prevalence of GS was also significantly higher in elite athletes (9.6 vs. 22%, p < 0.001) together with the tendency to higher frequencies of the genotypes (TA)_7/7 and (TA)_6/7UGT1A1.

Conclusion

Elite athletes have significantly higher concentrations of serum bilirubin, the most potent endogenous antioxidant substance known. Simultaneously, the prevalence of GS syndrome is also much higher in elite athletes, suggesting that a mild elevation of serum bilirubin might predispose to better sports performance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00463-6.

A Practical Approach to Monitoring Biomarkers of Inflammation and Muscle Damage in Youth Soccer Players During a 6-Month Training Cycle

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.

Blood Biomarkers Variations across the Pre-Season and Interactions with Training Load: A Study in Professional Soccer Players

Background: Pre-season training in soccer can induce changes in biological markers in the circulation. However, relationships between chosen hematological and biochemical blood parameters and training load have not been measured. Objective: Analyze the blood measures changes and their relationships with training loads changes after pre-season training. Methodology: Twenty-five professional soccer players were assessed by training load measures (derived from rate of perceived exertion- known as RPE) during the pre-season period. Additionally, blood samples were collected for hematological and biochemical analyses. Results: For hematological parameters, significant increases were found for platelets (PLT) (dif: 6.42; p = 0.006; d = -0.36), while significant decreases were found for absolute neutrophils count (ANC) (dif: -3.98; p = 0.006; d = 0.11), and absolute monocytes count (AMC) (dif: -16.98; p = 0.001; d = 0.78) after the pre-season period. For biochemical parameters, there were significant increases in creatinine (dif: 5.15; p = 0.001; d = -0.46), alkaline phosphatase (ALP) (dif: 12.55; p = 0.001; d = -0.84), C-reactive protein (CRP) (dif: 15.15; p = 0.001; d = -0.67), cortisol (dif: 2.85; p = 0.001; d = -0.28), and testosterone (dif: 5.38; p = 0.001; d = -0.52), whereas there were significant decreases in calcium (dif: -1.31; p = 0.007; d =0.49) and calcium corrected (dif: -2.18; p = 0.015; d = 0.82) after the pre-season period. Moreover, the Hooper Index (dif: 13.22; p = 0.01; d = 0.78), and all derived RPE measures increased after pre-season period. Moderate-to-very large positive and negative correlations (r range: 0.50-0.73) were found between the training load and hematological measures percentage of changes. Moderate-to-large positive and negative correlations (r range: 0.50-0.60) were found between training load and biochemical measures percentage of changes. Conclusions: The results indicated heavy physical loads during the pre-season, leading to a decrease in immune functions. Given the significant relationships between blood and training load measures, monitoring hematological and biochemical measures allow coaches to minimize injury risk, overreaching, and overtraining.

Haematological, Biochemical and Hormonal Biomarkers of Heat Intolerance in Military Personnel

Simple Summary

This study focuses on the biomarkers that are predictive of heat intolerance in military populations. Military personnel are at risk of exertional heat stroke when the body’s temperature increases during intense physical activity in hot weather. Exertional heat stroke (EHS) may accompany or precede heat intolerance, an unusual sensitivity to heat. However, it is unknown if blood biomarkers (haematological, biochemical and hormonal) are predictive of heat intolerance. We subjected a sample of Australian Defence Force personnel and civilian volunteers to a heat tolerance test (HTT), and blood samples were obtained pre-and post–HTT. The results showed that a history of EHS was associated with changes in creatinine and urea. The biochemical and hormonal biomarkers associated with heat intolerance were alanine amino transaminase, creatine kinase, cortisol and creatinine. Furthermore, creatinine and cortisol were identified as predictors and useful biomarkers of heat intolerance. This study also highlights the need for further exploration of genetic biomarkers to aid early identification and the return to duty process for military personnel who may be at risk of heat intolerance.

Abstract

Heat intolerance is the inability to withstand heat stress and this may occur due to exertional heat stroke (EHS). However, it is unknown if heat intolerance is associated with immune and hormonal disturbances. This study investigates haematological, biochemical and hormonal biomarkers related to heat intolerance and EHS in military and civilian volunteers. A quasi-experimental pre-and post-test design was used, with participants drawn from the Australian Defence Force (ADF) and the general populace. Blood samples were collected and analysed for biomarkers. Inferential statistics compared the biomarkers between the groups. Changes in alanine amino transaminase (p = 0.034), creatine kinase (0.044), cortisol (p = 0.041) and creatinine (p < 0.001) differed between the heat-intolerant and heat-tolerant groups. Participants with a history of EHS showed significant changes in creatinine (p = 0.022) and urea (p = 0.0031) compared to those without EHS history. Predictors of heat intolerance were increasing post-HTT creatinine and cortisol (OR = 1.177, p = 0.011 and OR = 1.015, p = 0.003 respectively). Conclusively, EHS history is associated with changes in creatinine and urea concentrations, while the predictors of heat intolerance are creatinine and cortisol. However, further exploration of other biomarkers, such as genetic polymorphism, is needed.

Acute Effects of Training Loads on Muscle Damage Markers and Performance in Semi-elite and Elite Athletes: A Systematic Review and Meta-analysis

BACKGROUND

The relationship between exercise-induced muscle damage (EIMD) indicators and acute training loads (TL) is yet to be reviewed extensively in semi-elite and elite athlete populations.

OBJECTIVES

The objectives of this systematic review and meta-analysis were threefold: (1) to evaluate studies of EIMD following the initial period of the preseason in semi-elite and elite athletes: (2) to examine acute physiological and performance responses across two periods of the season with similar TL; and (3) to examine acute physiological and performance responses to acute changes in TL during the season.

METHODS

The CINAHL, PubMed, Scopus, SPORTDiscus and Web of Science databases were systematically searched for studies that investigated: (1) semi-elite or elite athletes in team or individual sports following a periodised training programme; and (2) measured acute responses to training. Studies were excluded if: (1) conducted in animals; (2) non-English language; or (3) a conference abstract, review or case report. The Kmet Quality Scoring of Quantitative Studies tool was used for study appraisal.

SYNTHESIS METHODS

Data were quantitatively analysed by generating forest plots to report test statistics for statistical significance and inter-trial heterogeneity.

RESULTS

Of the included studies (n = 32), athletes experienced greater creatine kinase (CK) concentrations (Z = 4.99, p < 0.00001, I² = 74%), inflammatory factors and other indirect measures of muscle damage in the initial phase of the preseason period compared to the off-season; there were no changes in CK (Z = 1.43, p = 0.15, I² = 74%) across two time points of similar TL; and there were concurrent increases in CK with increases in TL (Z = 4.26, p < 0.0001, I² = 36%) and vice versa (Z = 4.33, p < 0.0001, I² = 79%).The qualitative analysis identified that the response of inflammatory factors and other indirect measures of muscle damage to changes in load were inconclusive.

LIMITATIONS

This review included varying age, sex, sports and competition levels. The group level meta-analysis failed to identify within-athlete or position-specific differences across time.

CONCLUSION

Blood biomarkers of EIMD may not differ across periods of similar TL, however can be considered a sensitive monitoring tool for assessing responses following acute TL changes in semi-elite and elite athletes.

The Influence of Training Load on Hematological Athlete Biological Passport Variables in Elite Cyclists

The hematological module of the Athlete Biological Passport (ABP) is used in elite sport for antidoping purposes. Its aim is to better target athletes for testing and to indirectly detect blood doping. The ABP allows to monitor hematological variations in athletes using selected primary blood biomarkers [hemoglobin concentration (Hb) and reticulocyte percentage (Ret%)] with an adaptive Bayesian model to set individual upper and lower limits. If values fall outside the individual limits, an athlete may be further targeted and ultimately sanctioned. Since (Hb) varies with plasma volume (PV) fluctuations, possibly caused by training load changes, we investigated the putative influence of acute and chronic training load changes on the ABP variables. Monthly blood samples were collected over one year in 10 male elite cyclists (25.6 ± 3.4 years, 181 ± 4 cm, 71.3 ± 4.9 kg, 6.7 ± 0.8 W^.kg^-1 5-min maximal power output) to calculate individual ABP profiles and monitor hematological variables. Total hemoglobin mass (Hbmass) and PV were additionally measured by carbon monoxide rebreathing. Acute and chronic training loads-respectively 5 and 42 days before sampling-were calculated considering duration and intensity (training stress score, TSS^TM). (Hb) averaged 14.2 ± 0.0 (mean ± SD) g^.dL^-1 (range: 13.3-15.5 g·dl^-1) over the study with significant changes over time (P = 0.004). Hbmass was 1030 ± 87 g (range: 842-1116 g) with no significant variations over time (P = 0.118), whereas PV was 4309 ± 350 mL (range: 3,688-4,751 mL) with a time-effect observed over the study time (P = 0.014). Higher acute-but not chronic-training loads were associated with significantly decreased (Hb) (P <0.001). Although individual hematological variations were observed, all ABP variables remained within the individually calculated limits. Our results support that acute training load variations significantly affect (Hb), likely due to short-term PV fluctuations, underlining the importance of considering training load when interpreting individual ABP variations for anti-doping purposes.

Changes in γH2AX and H4K16ac levels are involved in the biochemical response to a competitive soccer match in adolescent players

The aim of this study was to examine novel putative markers of the response to the competitive soccer match in adolescent players, such as changes in global levels of γH2AX and H4K16ac in the chromatin of peripheral mononuclear blood cells (PMBCs) and a Fourier-transform infrared spectroscopy (FTIR)-based biochemical fingerprint of serum. These characteristics were examined with reference to the physiological and metabolic aspects of this response. Immediately post-match we noticed: (1) a systemic inflammatory response, manifesting as peaks in leukocyte count and changes in concentrations of IL-6, TNFα, and cortisol; (2) a peak in plasma lactate; (3) onset of oxidative stress, manifesting as a decline in GSH/GSSG; (4) onset of muscle injury, reflected in an increase in CK activity. Twenty-four hours post-match the decrease in GSH/GSSG was accompanied by accumulation of MDA and 8-OHdG, macromolecule oxidation end-products, and an increase in CK activity. No changes in SOD1 or GPX1 levels were found. Repeated measures correlation revealed several associations between the investigated biomarkers. The FTIR analysis revealed that the match had the greatest impact on serum lipid profile immediately post-game. In turn, increases in γH2AX and H4K16ac levels at 24 h post-match indicated activation of a DNA repair pathway.

Blood Biomarkers of Recovery Efficiency in Soccer Players

Physical exercise strongly affects human metabolism and causes biochemical changes. This study aimed to investigate the relationship between routine plasma biomarker levels and recovery efficiency in soccer players during an entire competitive match season. The players participating in the study were divided into a midfielder/defender group (seven midfielders and seven defenders) and a goalie/substitute group (six persons—goalkeepers and players with a short cumulative match-time). The fasting capillary blood samples were taken 17–24 h after each competitive match. The blood plasma was used to determine the creatinine, urea, alkaline phosphatase, creatine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase, iron and magnesium levels of the athletes. The levels of (AST) (aspartate aminotransferase), (ALT) (alanine aminotransferase) and (Cr) creatinine were higher in the midfielder/defender group than in the control group, but only AST and Cr significantly varied over time (AST decreased, and Cr increased with time). The (LDH) (lactate dehydrogenase) activity and urea level were significantly lower in the midfielder/defender group than in the goalie/substitute group, and it significantly varied over time (LDH decreased, and urea increased with time). No differences in the (CK) creatine kinase and (ALP) alkaline phosphatase activities between the groups was found, although CK increased significantly with time in the midfielder/defender group (particularly midfielders in the spring round). In midfielders, the AST activity and the iron level were significantly lower in the spring than in the autumn round. On the contrary, ALT, CK, urea and magnesium levels were significantly higher in the spring than in autumn round. A long-term measurement of biochemical parameters in elite soccer players indicated that AST, CK, LDH and creatinine levels, when analyzed together, could constitute a useful set of markers for monitoring recovery periods.

Relationship of Pre-season Training Load With In-Season Biochemical Markers, Injuries and Performance in Professional Soccer Players

INTRODUCTION

There is controversy in the literature in regards of the link between training load and injury rate. Thus, the aims of this non-interventional study were to evaluate relationships between pre-season training load with biochemical markers, injury incidence and performance during the first month of the competitive period in professional soccer players.

MATERIALS AND METHODS

Healthy professional soccer players were enrolled in this study over two pre-season periods. Data sets were available from 26 players during the first season (2014-2015) and 24 players during the second season (2015-2016) who completed two pre-season periods (6 weeks each). External training load was assessed from all athletes during training using Global Positioning System (GPS). Internal training load was monitored after each training session using rate of perceived exertion (RPE). Before and after each pre-season, blood samples were taken to determine plasma lactate dehydrogenase (LDH), creatine kinase (CK) and C-reactive protein (CRP). Injury incidence and overall performance (ranking of the team after the first five official games of the championship) were recorded for both seasons separately.

RESULTS

There was no statistically significant difference in mean RPE values of the two-preparation periods (2737 ± 452 and 2629 ± 786 AU, p = 0.492). The correlational analysis did not reveal significant associations between internal and external training load (RPE and GPS data) and biological markers. There was a significant positive correlation between RPE and LDH during the 2015/2016 season (r = 0.974, p = 0.001). In addition, a significant negative correlation was found between total distance >20 km/h and CRP during the 2015-2016 season (r = -0.863, p = 0.027). The injury rates for the two seasons were 1.76 and 1.06 per 1000 h exposure for the 2014-2015 and 2015-2016 seasons, respectively (p = 0.127).

CONCLUSION

Our study showed that pre-season training load is not associated with overall team performance. This association is most likely multifactorial and other factors (e.g., technical and tactical level of the team, opponents, environment) may play an important role for the collective team performance. Our findings may help coaches to better prepare their athletes during pre-season.

Training-Induced Variations in Haematological and Biochemical Variables in Adolescent Athletes of Arab Origin Throughout an Entire Athletic Season

The purpose of this study was to observe and report variations in several haematological and biochemical markers throughout an entire athletic season in a large cohort of adolescent athletes of Arab origin. Blood samples were collected from 72 adolescent male athletes at 4 selected time points during their training season. Results expressed in relation to plasma volume were corrected accordingly and significant variations in several variables emerged. Initial uncorrected haematological results revealed that haematocrit (Hct) and mean cell volume (MCV) concentrations noticeably increased at the competitive period (T3) and before the start of the following preseason (T4), whereas reticulocytes equivalent (Ret-He) only rose at T4 phase (p < 0.01). Conversely, corrected red blood cells (RBC), haemoglobin (Hb) and mean cell haemoglobin concentration (MCHC) progressively decreased over the year (p < 0.001). From the electrolytes panel, sodium and chloride considerably reduced at the peak of the training period (T2) to the start of the next preseason (T4), while a significant fall in potassium was mainly observed during the competitive period (T3) (p < 0.001). Coaches and sport scientists could use the results of this study to evaluate typical variations of each age group in order to diagnose potential adverse effects of high training loads, assist in the design of training programs and/or clinical interventions that will safeguard athletes’ health, and consider the important role of plasma volume for the interpretation of results.

High-sensitivity Troponins after a Standardized 2-hour Treadmill Run

BACKGROUND

The aim of this study was to examine high-sensitivity troponin T and I (hsTnT and hsTnI) after a treadmill run under laboratory conditions and to find a possible connection with echocardiographic, laboratory and other assessed parameters.

METHODS

Nineteen trained men underwent a standardized 2-hour-long treadmill run. Concentrations of hsTnT and hsTnI were assessed before the run, 60, 120 and 180 minutes after the start and 24 hours after the run. Changes in troponins were tested using non-parametric analysis of variance (ANOVA). The multiple linear regression model was used to find the explanatory variables for hsTnT and hsTnI changes. Values of troponins were evaluated using the 0h/1h algorithm.

RESULTS

Changes in hsTnT and hsTnI levels were statistically significant (p<0.0001 and p<0.0001, respectively). In a multiple regression model (adjusted R2: 0.60, p=0.005 for hsTnT and adjusted R2: 0.60, p=0.005 for hsTnI), changes in both troponins can be explained by relative left wall thickness (LV), training volume, body temperature after the run and creatinine changes. According to the 0h/1h algorithm, none of the runners was evaluated as negative.

CONCLUSIONS

Relative LV wall thickness, creatinine changes, training volume and body temperature after the run can predict changes in hsTnT and hsTnI levels. When medical attention is needed after physical exercise, hsTn levels should be tested only when clinical suspicion and the patient's history indicate a high probability of myocardial damage.

ACTH, Cortisol and IL-6 Levels in Athletes following Magnesium Supplementation

BACKGROUND

Physical exercise activates the hypothalamo-pituitary-adrenal (HPA) axis and induces the body's inflammatory response. Due to contemporary dietary habits and increased energy expenditure, athletes are susceptible to depletion of magnesium ions. The aim of our study was to investigate, through assessment of plasma ACTH, serum IL-6, and salivary/serum cortisol levels, if chronic magnesium supplementation might reduce damaging stress effects in amateur rugby players.

METHODS

Rugby players (N=23) were randomly assigned to intervention and control group. Basal samples were collected before intervention group started a 4-week-long supplementation with magnesium (500 mg Mg/d). Blood and saliva sampling were done a day before the match (Day-1), on the morning of competition (Game), and during a six-day-long recovery period (Day1, Day3 and Day6). ACTH, serum/salivary cortisol, IL-6 and total/differential leukocytes counts were determined at each time point.

RESULTS

There was a statistically significant increase in ACTH concentration in intervention group compared to control group, while reductions in cortisol concentrations between the two groups were the greatest at Day-1 (p < 0.01) and at the day of competition (Game) (p < 0.01). Our results revealed that magnesium completely abolished the increase in IL-6 level noted in control group on Day1 and Day3 vs. Day-1 (p < 0.01) and also diminished the rise in neutrophil/lymphocyte ratio in intervention group vs. control group (p < 0.01).

CONCLUSIONS

These results suggest the possibly important influence magnesium supplementation might have on the change of parameters of HPA axis activity and reduction of immune response activation following strenuous physical exercise such as a rugby game.