Miroslav Krajcigr

Background: Red Bull (RB) is widely consumed by athletes in an effort to enhance performance through its stimulant content, primarily caffeine and taurine. Although its potential ergogenic effects have been studied, evidence regarding the impact of commercially available servings of RB on short-term anaerobic performance remains inconsistent. Aim: This study examined whether acute ingestion of a standard commercially available serving of RB influences anaerobic power, handgrip strength, and jumping ability in female sub-elite volleyball players. Methods: Fifteen female sub-elite volleyball players (mean age 21.3 ± 2.4 years) participated in a randomized, double-blind, placebo-controlled crossover study. Each athlete completed three physical tests (Wingate anaerobic test, jump test, and handgrip strength test) on two occasions, separated by 1 week, after consuming either RB or a placebo designed to mimic its taste and appearance. Participants ingested 250.7 ± 28.2 mL of RB, providing 80.3 ± 9.0 mg of caffeine (1.143 mg·kg ⁻¹ ). Performance testing began 33 min after ingestion. Performance outcomes were compared between conditions using paired t-tests. Summary: None of the 13 measured performance variables showed statistically significant differences (p > 0.05) between RB and placebo trials. Eight participants reported mild nausea following RB consumption. Under the conditions of this study, consumption of a standard commercially available serving of RB (∼1.143 mg·kg ⁻¹ caffeine) did not produce measurable improvements in anaerobic performance, handgrip strength, or jump ability, suggesting that a single serving does not confer meaningful performance benefits for short-duration, high-intensity exercise in female sub-elite volleyball players.

Background: Serve effectiveness plays a critical role in volleyball, influencing the opponent’s reception and subsequent attack. While smash serves are powerful, float serves may disrupt the opponent through unpredictable flight patterns. This study examined how serve type and speed affect reception quality in elite men’s volleyball. Methods: A total of 543 serves (254 float, 289 smash) from one Czech Extraliga team across seven home matches were analyzed using video recordings and radar measurements. Serve speeds were grouped into predefined categories. Effectiveness was defined as the sum of effective receptions and aces; error serves were excluded. Reception outcomes were classified as effective or ineffective. Descriptive statistics were calculated. A Chi-square test assessed the association between serve type and reception outcome. Effect size was measured using Cramer’s V, and 95% confidence intervals were computed. Results: Smash serves showed significantly higher effectiveness (45.7%) than float serves (27.6%), and a higher ace rate (10.7% vs. 4.7%). Smash serves of ≥101 km/h were the most effective (77.6%, 20.4% aces). The Chi-square test confirmed a significant association between the serve type and the reception outcome (χ²(1) = 37.21, p < .001), with Cramer’s V = 0.185. Conclusions: Serve type and speed affect reception success. Smash serves yield more direct points, while float serves consistently disrupt opponent offense. Coaches should apply both types to vary tactical pressure.

The purpose of the study was to determine whether running is associated with greater bone mineral density (BMD) by comparing the BMD of regularly active male runners (AR) with inactive nonrunner male controls (INC). This cross-sectional study recruited 327 male AR and 212 male INC (aged 18–65) via a stratified recruitment strategy. BMD of the whole body (WB) and partial segments (spine, lumbar spine (LS), leg, hip, femoral neck (FN), and arm for each side) were measured by dual-energy x-ray absorptiometry (DXA) and lower leg dominance (dominant-D/nondominant-ND) was established by functional testing. An ANCOVA was used to compare AR and INC. The AR had greater BMD for all segments of the lower limb (p0.05) compared with INC. Based on the pairwise comparison of age groups, AR had greater BMD of the ND leg in every age group compared with INC (p<0.05). AR had grater BMD of the D leg in every age group except for (26–35 and 56–65) compare with INC (p<0.05). In the youngest age group (18–25), AR had greater BMD in every measured part of lower extremities (legs, hips, femoral necks) compared with INC (p<0.05). In the 46–55 age group AR had greater BMD than INC (p < 0.05) only in the WB, D Leg, D neck, and ND leg. In the 56–65 age group AR had greater BMD than INC (p<0.05) only in the ND leg. Overall, AR had greater BMD compared with INC in all examined sites except for the upper limbs, supporting the notion that running may positively affect bone parameters. However, the benefits differ in the skeletal sites specifically, as the legs had the highest BMD difference between AR and INC. Moreover, the increase in BMD from running decreased with age.

Diver training improves physical and mental fitness, which can also benefit other sports. This study investigates the effect of eight weeks of static apnea training on maximum apnea time, and on the physiological parameters of runners, swimmers, and sedentary participants, such as forced vital capacity (FVC), minimum heart rate (HR), and oxygen saturation (SpO₂). The study followed 19 participants, including five runners, swimmers, sedentary participants, and four competitive divers for reference values. The minimum value of SpO₂, HR, maximum duration of apnea, and FVC were measured. Apnea training occurred four times weekly, consisting of six apneas with 60 s breathing pauses. Apnea duration was gradually increased by 30 s. The measurement started with a 30 s apnea and ended with maximal apnea. There was a change in SpO₂ decreased by 6.8%, maximum apnea length increased by 15.8%, HR decreased by 9.1%, and FVC increased by 12.4% for the groups (p < 0.05). There were intra-groups changes, but no significant inter-groups difference was observed. Eight weeks of apnea training improved the maximum duration of apnea, FVC values and reduced the minimum values of SpO₂ and HR in all groups. No differences were noted between groups after training. This training may benefit cardiorespiratory parameters in the population.

Context: Flossing is still a relatively new technique that has yielded varied results in the research literature; therefore, it requires further investigation. Previous research has shown that thigh tissue flossing might improve performance in countermovement jump, sprint time, maximum voluntary contraction, and rate of force development. Design: The present study aims to investigate the effect of the floss band on performance during the Wingate test (30-WAT), muscle oxygen saturation (SpO₂), and total hemoglobin in vastus lateralis. Methods: Twenty-two students of physical education and sport (11 men and 11 women) were randomly selected to complete either the Wingate test with the application of a floss band in warm-up or the Wingate test without the use of a floss band, followed by the alternative 24 hours apart. Results: Throughout the testing, the floss band did not affect performance values during the Wingate test (relative peak power, relative average power, and fatigue index). However, there was a medium to large effect difference during 1 minute prior to 30-WAT (PRE), during the 30-WAT, and 10-minute recovery (REC) in values of SpO₂ and total hemoglobin. Use of floss band displayed a higher SpO₂ during PRE, 30-WAT, and REC by ∼13.55%, d < 2; ∼19.06%, d = 0.89; and ∼8.55%, d = 0.59, respectively. Conclusion: Collectively, these findings indicate that the application of thigh flossing during warm-up has no effect on 30-WAT performance; however, SpO₂ was significantly increased in all stages of testing. This could lead to potential improvement in repeated anaerobic exercise due to increased blood flow. Increased muscle oxygen saturation can also lead to improved tissue healing as oxygen supply is essential for tissue repair, wound healing, and pain management.

Article: Relationship between body composition and anaerobic power with inter-limb difference dependence in Czech elite ice hockey players - The Journal of Sports Medicine and Physical Fitness 2023 Jul 10 - Minerva Medica - Journals

Regular physical activity (PA) plays an important role in the prevention of several noninfectious chronic diseases, partly due to its positive effects on body composition. The relationship between the amount of weekly PA and body composition in premenopausal women, however, remains unclear. The objective of the study is to assess the relationship between body composition and the volume of PA in full-time employed premenopausal women. The study included 136 women (aged 41.07 ± 2.77 years). The women were divided into tertiles (T1–T3) according to the level of total reported weekly PA. T1 were women with the lowest volume of PA, T2 were women with a medium volume, and T3 were women with the highest PA volume. DXA was used to measure body mass (BM), body fat (BF), visceral fat (VFA), and fat-free mass (FFM). For the comparison of means, we used one-way ANOVA and a t test. Practical significance was verified with effect of size. Significant differences were found between women in T1 vs. T2 and T1 vs. T3. When compared with T2, T1 women had a higher BM (+6.10 kg), BF (+5.98 kg), BF (+5.42%), and VF (+17.49 cm²). When compared with T3, T1 women had a higher BM (+5.99 kg), BF (+6.42 kg), BF (+5.89%), and VFA (+20.71 cm²). We can conclude that a higher volume of weekly PA is associated with lower BF, but appears to have no effect on FFM.