Acute Effects of Caffeinated Chewing Gum on Volleyball Performance in High-Performance Female Players.

To date, no investigation has studied the effect of acute intake of caffeinated chewing gum on volleyball performance. Therefore, the aim of this investigation was to establish the impact of caffeinated chewing gum ingestion on physical performance in female volleyball players. Twelve high-performance volleyball female athletes participated in a randomized, crossover, placebo-controlled, and double-blind experiment. Each athlete performed two identical experimental sessions after a) ingestion of ~6.4 mg/kg of caffeine via caffeinated chewing gum, b) ingestion of non-caffeinated chewing gum as a placebo. After the ingestion of gum, athletes performed a volleyball game, and performance was assessed by a notational analysis. Just before and after the game, jump performance during block and attack actions was evaluated. The number of points obtained and the number of errors committed during serve, reception, attacking, and blocking actions were unaffected by the ingestion of caffeinated chewing gum (p from 0.066 to 0.890). However, caffeinated chewing gum increased jump attack height in comparison to the placebo (pre-game 46.0 ± 7.2 vs. 47.2 ± 6.7 cm, p = 0.032; post-game 46.3 ± 7.6 vs. 47.5 ± 6.9 cm, p = 0.022, respectively). Caffeinated chewing gum did not modify block jump height (pre-game 32.7 ± 5.5 and 33.0 ± 4.3 cm, p = 0.829; post-game: 34.8 ± 6.1, 35.4 ± 6.1 cm, p = 0.993, respectively). The ingestion of ~6.4 mg/kg of caffeine via caffeinated chewing gum was effective for improving jump attack performance in women volleyball athletes. However, this effect was not translated into better volleyball performance during a game.

Diagnostic Accuracy of Platelet-Derived Parameters in Prognostication in Neurosurgery.

Introduction. Platelets (PLT) are key mediators in thrombotic and inflammatory processes. Their activity increases with size, so the mean platelet volume (MPV) can be a potential predictor of perioperative complications. The aim of the study was to assess the suitability of platelet parameters in predicting the risk of hospital death in neurosurgery. Methods. Retrospective observation covered 452 patients undergoing surgery in the period March 2018−August 2018. High-risk patients accounted for 44% (i.e., ASA-PS class III+) and 9% (i.e., ≥1 Shoemaker criterion), respectively, and 14% of procedures were performed in the urgent mode. The preoperative platelet parameters that were assessed and analysed were: total platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT) and platelet distribution width (PDW). The end point of the study was a hospital death. Results. Before discharge from the hospital, 13 patients died. The medians (IQR) PLT, MPV PDW and PCT were, respectively: 230 × 106 L−1 (182−279); 9.2 fL (8.3−10.1); 14% (12.5−16.3); and 21% (17−26). PLT, PCT and PDW were not useful in the risk assessment. MPV was lower in patients who died (9.3 vs. 8.3 fL, p < 0.01) and predicted death occurred in 76% (AUC = 0.76, 95%CI 0.72−0.80, p < 0.01). Further, after adjustment for confounders, MPV remained a significant predictor of in-hospital death (logOR[MPV] = 0.31, AUC = 0.94, 95%CI 0.92−0.96, p = 0.02). Conclusion. The reduction in the average volume of platelets is associated with a worse prognosis in neurosurgical patients.

Diagnostic accuracy of red blood cell distribution width in predicting in-hospital mortality in patients undergoing high-risk gastrointestinal surgery

BACKGROUND: The red blood cell distribution width index (RDW) is one of several parameters routinely analysed in peripheral blood counts. The aim of the study was to assess the usefulness of RDW in the prediction of in-hospital mortality in patients undergoing high-risk gastroenterological surgery. METHODS: Prospective observation covered 229 patients who underwent surgery, for whom the risk of cardiovascular complications was high due to the type of procedure. The patient's individual risk was assessed using the criteria of the American Society of Anesthesiologists (ASA-PS). Peripheral blood for morphological examination was collected preoperatively. The following parameters of the red blood cell system were evaluated: red blood cell count (RBC), haemoglobin (Hgb), haematocrit (Hct), mean corpuscular volume (MCV), RDW expressed as a standard deviation (SD) and a coefficient of variation (CV). The occurrence of hospital death was the main endpoint. RESULTS: Patients who died had had statistically significantly lower RBC, Hgb and Hct values, as well as higher RDWSD and RDW-CV values. Both the preoperative RDW-SD and RDW-CV values predicted the outcome, respectively: AUC RDW-SD = 0.744 (95% CI: 0.683­0.799; P < 0.001), AUC RDW-CV = 0.762 (95% CI: 0.702­0.816; P < 0.001). In logistic regression, it was confirmed that RDW predicted mortality (OR RDW-SD = 1.21; P < 0.001, OR RDW-CV = 1.62; P = 0.01), even after adjustment for individual risk and other erythrocyte parameters. CONCLUSION: RDW is a valuable screening predictor of in-hospital mortality in patients undergoing high-risk gastroenterological surgery, regardless of the estimated individual risk and the value of other erythrocyte parameters. Evaluation of the RDW may be helpful in the identification of patients requiring correction of haematological disorders in the pre-operative period, as well as, in particular, surveillance in the perioperative period.

Post-Effort Changes in Activity of Traditional Diagnostic Enzymatic Markers in Football Players' Blood.

BACKGROUND: Long-term and intensive physical effort causes metabolic and biochemical adaptations for both athletic and non-athletic objectives. Knowing the importance of aerobic training in football players, the aim of this study was to evaluate changes in the activity of: creatinine kinase (CK), creatine kinase MB (CKMB), lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (HBDH), cholinesterase (ChE) and alkaline phosphatase (ALP) in response to a semi-long distance outdoor run under aerobic conditions among both female and male football players. METHODS: Sixteen participants aged 21.9±2 years (women) and 18.4±0.5 years (men), all of them voluntarily recruited football players, took part in an outdoor run, the women covering a distance of 7.4±0.3 km while men covered a distance of 10.7±1.0 km. Plasma activities of the studied enzymes were determined using an appropriate diagnostic assay kit. RESULTS: Our results indicate that total LDH activity could be a useful tool in evaluating physical fitness among athletes. We simultaneously established that ChE could not be a marker useful in assessing metabolic response to physical effort in athletes. Moreover, our results suggest that post-effort changes in ALP activity might be used to estimate early symptoms of certain vitamin deficiencies in an athlete's diet. CONCLUSIONS: We confirmed that the assessment of activity of selected traditional diagnostic enzymatic markers provides information about muscle state after physical effort.

Could biochemical liver profile help to assess metabolic response to aerobic effort in athletes?

Monitoring and optimizing the effectiveness of training course require wide analyses of athletes' blood parameter changes. The aim of this study was to evaluate the usefulness of biochemical liver profile to assess the metabolic response to semi-long-distance outdoor run in football players. Sixteen football players run outdoor for 60 minutes to achieve aerobic metabolism. Plasma activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyltransferase (GGT) and plasma levels of total and direct bilirubin were determined in samples obtained before exercise test (pre-exercise) and immediately after the run (post-exercise). Mean AST plasma activity (U·L-1) before/after the exercise, respectively, was 78.3/228.3 in women and 76.5/56.2 in men. Mean ALT plasma activity (U·L-1) before/after the exercise, respectively, was 27.5/59.1 in women and 36.2/35.3 in men. Mean GGT plasma activity (U·L-1) before/after the exercise, respectively, was 39.3/76.6 in women and 44.7/71.2 in men. Plasma levels of total and direct bilirubin were similar before and after the run regardless of the gender. Statistical significance of the differences between results obtained pre- and post-exercise occurred in women (p = 0.0212 for AST; p = 0.0320 for ALT; p = 0.0067 for GGT, respectively). The training monitoring in athletes should be performed using measurements of performance and biological or physiological parameters. It was found that AST, ALT, and GGT activities could be a valuable tool to assess the metabolic response in high-level fitness female athletes. Therefore, monitoring of those well-known diagnostic markers could prevent the trainee from harmful overtraining.

Association of the MTHFR 1298A>C (rs1801131) polymorphism with speed and strength sports in Russian and Polish athletes.

It has been suggested that DNA hypomethylation because of poorer effectiveness of the 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme induces muscular growth. We hypothesised that the common, functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. To test this hypothesis, we investigated the distribution of the 1298A>C variant in Polish (n = 302) and Russian (n = 842) athletes divided into four groups: endurance, strength-endurance, sprint-strength and strength-endurance, as well as in 1540 control participants. We found different genotypes (the AC heterozygote advantage) and allele distributions among sprint-strength athletes and strength athletes than the groups of sedentary controls for each nationality. In the combined study, the allelic frequencies for the 1298C variant were 35.6% in sprint-strength athletes (OR 1.18 [1.02-1.36], P = 0.024 vs. controls) and 38.6% in strength athletes (OR 1.34 [1.10-1.64], P = 0.003 vs. controls). The results of the initial and repetition studies as well as the combined analysis suggest that the functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. The presence of the C allele seems to be beneficial in sprint-strength and strength athletes. It needs to be established whether and to what extent this effect is mediated by alteration in DNA methylation status.

The -9/+9 polymorphism of the bradykinin receptor Beta 2 gene and athlete status: a study involving two European cohorts.

Previous studies concerning the relevance of BDKRB2 gene polymorphisms revealed that the absence (-9 allele) of a nine-base-pair sequence in exon 1 of the BDKRB2 gene is correlated with higher skeletal muscle metabolic efficiency, glucose uptake during exercise, and endurance athletic performance. The aim of the study was to investigate the association between the BDKRB2 -9/+9 polymorphism and elite athletic status in two cohorts of eastern European athletes. We examined the genotype distribution of the BDKRB2 9/+9 polymorphic site in a group of Polish athletes and confirmed the results obtained in a replication study of Russian athletes. Three hundred and two Polish athletes and 684 unrelated sedentary controls, as well as 822 Russian athletes and 507 unrelated sedentary volunteers, were recruited for this study. All samples were genotyped for the -9/+9 polymorphism within exon 1 of the BDKRB2 gene using polymerase chain reaction. Significance was assessed by chi square analysis with Bonferroni's correction for multiple testing. We found no statistical difference in the -9/+9 genotype and allele frequencies in two groups of athletes divided into four subgroups: endurance, sprint-endurance, sprint-strength, and strength athletes, compared with controls. There were no significant differences in allele frequencies (p = 0.477) and genotype distribution (p = 0.278) in the initial and replication studies. Thus, no association was found between the BDKRB2 -9/+9 polymorphism and elite athletic status in two cohorts of eastern European athletes.