It was the Summer Olympic Games 1968 held in Mexico City (2,300 m) that required scientists and coaches to cope with the expected decline of performance in endurance athletes and to establish optimal preparation programs for competing at altitude. From that period until now many different recommendations for altitude acclimatization in advance of an altitude competition were proposed, ranging from several hours to several weeks. Those recommendations are mostly based on the separate consideration of the physiology of acclimatization, psychological issues, performance changes, logistical or individual aspects, but there is no review considering all these aspects in their entirety. Therefore, the present work primarily focusses on the period of altitude sojourn prior to the competition at altitude based on physiological and psychological aspects complemented by nutritional and sports practical considerations.

Background/Aims: Central dopaminergic activity is probably linked to regulation of glucose and lipid metabolism and weight maintenance. The aim of our study was to evaluate the relationship between central dopaminergic activity measured using the apomorphine challenge test and metabolic parameters in healthy men. Methods: Forty-two healthy men (average age 43.5 ± 7.4 years, body mass index, BMI, 27.4 ± 5.7) were examined anthropometrically and biochemically (glycemia, lipids, glycated hemoglobin). Central dopaminergic activity was assessed as the area under the curve (AUC) of prolactin (PRL) and growth hormone (GH) responses to the apomorphine challenge test after sublingual administration of apomorphine in a dose of 0.033 mg/kg. Insulin resistance was quantified by calculation of glucose disposal and metabolic clearance rate during a euglycemic hyperinsulinemic clamp on two insulin levels (1 and 10 mIU/kg/min). Linear regression was used for statistical analysis. Results: Hormonal responses correlated negatively with age (for AUC/GH r = -0.33; p = 0.031) and BMI (AUC/GH r = -0.41; p = 0.007). After adjustment for age and BMI, a statistically significant negative correlations between AUC/PRL and total cholesterol (r = -0.41; p = 0.007), AUC/GH and HbA1c (r = -0.37; p = 0.016) and AUC/GH and HOMA (homeostasis model assessment; r = -0.345; p = 0.025) were observed. Conclusion: Central dopaminergic activity declines with age and BMI. Higher total cholesterol, glycated hemoglobin and insulin resistance parameters are connected with lower central dopamine tone.

Regular physical activity is a very important factor in the healthy development of an individual and an essential part of a healthy lifestyle. However, today’s population still suffers from an insufficient amount of exercise caused mainly by technological progress and often inappropriate conditions for practising sports. In relation to this, we are grappling with a steady increase in obesity. During the COVID-19 pandemic, conditions for regular physical activity became even more unfavourable, with the declaration of a state of emergency and antipandemic measures leading to the closure of sports grounds and sporting competitions. Using a questionnaire survey of a sample of children (n = 1456), we found that, already before the pandemic, 69% of the observed sample had not met the recommended amount of physical activity, and only 67% of the sample was of normal weight. By comparing both groups after the end of pandemic restrictions, we found statistically significant differences at examined indicators of the children’s Body Mass Index (BMI), their physical activity, and free time spending habits. We noticed the significant differences in BMI indicators in two different categories, normal weight (7.5%) and stage 1 obesity (1.66%). Simultaneously, we noticed differences in the children’s physical activities, especially with children who attend sports playgroups connected to athletic development (8.74%). More differences were noticed in free time spending habits indicators; the most significant ones were with the children who spend their free time behind the personal computer for more than 14 h a week (5.4%) and with the children who spend their free time on social media for 8–14 h a week (18.56%).

The objective of this study was to determine the anthropometric and somatotype differences between elite single-canoeists (C1) included in the white-water slalom Czech national team (NT) (n = 5) and others (n = 12) who did not qualify for the national team (DNQ) leading up to the Olympic Games in Rio de Janiero, 2016. All paddlers were measured using a battery of 40 anthropometric parameters in one day, 4 weeks before competing in the Czech national selection races. The NT racers had a significantly (p < 0.05) greater circumference of the forearm (27.8 ± 0.6 vs. 26.8 ± 1.4) and upper arm (35.60 ± 1.5 vs. 33.5 ± 1.7) for the dominant paddling arm, as well as a greater chest circumference (98.3 ± 2.4 vs. 93.9 ± 2.3). Additionally, the sum of triceps, scapular, calf, and supraspinal skinfolds were significantly less in NT. There were no significant differences in height (p = 0.14), body mass (p = 0.18) or circumferences of the lower extremities (p = 0.09-0.32). Somatotype was statistically similar (p = 0.06-0.13), but practically different (NT = 1.4-5.6-2.3; DNQ = 1.6-4.6-3.1) such as body fat percentage (NT = 7.5 ± 2.3; DNQ = 9.1 ± 1.6). Based on the results of this study we can recommend that single-canoeists seeking to achieve elite performance should participate in training that focuses on maximizing the musculature of the upper limbs and chest while maintaining minimal body fat. The current data also shows that experience likely plays a role in national team selection, as NT were an average of 5.5 years older than DNQ.

ABSTRACT:The objective of the pilot study was to test the effect of inhaling 99.5% oxygen on recovery. The source of concentrated oxygen was O-PUR (Oxyfit). Research subjects completed two thirty-second Wingate tests at an interval of ten minutes, and in the interval between the tests the subjects inhaled either oxygen or a placebo in random order. This procedure was then repeated. The pilot study revealed a significantly (p<0.03) smaller performance drop in the second Wingate test following the inhalation of 99.5% oxygen when compared with the placebo. The results of the study indicate that inhaling concentrated oxygen may have a positive effect on short-term recovery processes. KEY WORDS: concentrated oxygen, anaerobic capacity, Wingate test, recovery speedconditions it is possible to increase the intensity of exertion during hyperoxic breathing. Symptoms of hyperventilation and the associated respiratory alkalosis (tachycardia, sweating, pins and needles, muscle spasms or shortened reflex times) have not been observed during the application of an increased concentration of oxygen. The inhalation of oxygen in higher concentrations leads to an increase in the arterial partial pressure of oxygen [16].