Background: Ventilatory efficiency (VE/VCO₂) is a strong predictor of cardiovascular diseases and defines individuals’ responses to exercise. Its characteristics among endurance athletes (EA) remain understudied. In a cohort of EA, we aimed to (1) investigate the relationship between different methods of calculation of VE/VCO₂ and (2) externally validate prediction equations for VE/VCO₂. Methods: In total, 140 EA (55% males; age = 22.7 ± 4.6 yrs; BMI = 22.6 ± 1.7 kg·m⁻²; peak oxygen uptake = 3.86 ± 0.82 L·min⁻¹) underwent an effort-limited cycling cardiopulmonary exercise test. VE/VCO₂ was first calculated to ventilatory threshold (VE/VCO₂-slope), as the lowest 30-s average (VE/VCO₂-Nadir) and from whole exercises (VE/VCO₂-Total). Twelve prediction equations for VE/VCO₂-slope were externally validated. Results: VE/VCO₂-slope was higher in females than males (27.7 ± 2.6 vs. 26.1 ± 2.0, p < 0.001). Measuring methods for VE/VCO₂ differed significantly in males and females. VE/VCO₂ increased in EA with age independently from its type or sex (β = 0.066–0.127). Eleven equations underestimated VE/VCO₂-slope (from −0.5 to −3.6). One equation overestimated VE/VCO₂-slope (+0.2). Predicted and observed measurements differed significantly in nine models. Models explained a low amount of variance in the VE/VCO₂-slope (R² = 0.003–0.031). Conclusions: VE/VCO₂-slope, VE/VCO₂-Nadir, and VE/VCO₂-Total were significantly different in EA. Prediction equations for the VE/VCO₂-slope were inaccurate in EA. Physicians should be acknowledged to properly assess cardiorespiratory fitness in EA.

While the training of professional sports athletes and the factors determining sports success are based on well-established scientific research, esports training and markers of esports performance are not yet fully recognized or explored. Knowledge of the psychophysiological responses of the athlete’s body to esports competition is the necessary foundation for rational training management. The aim of the present study was to evaluate physiological stress while playing Counter-Strike: Global Offensive (CS:GO). Selected cardiovascular, hormonal, and biochemical indices were monitored to assess differences in stress responses between winners and losers. Twenty-two male players participated in the study (age 22.0 ± 2.0 years, CS:GO training experience 7.0 ± 2.2 years, training load 24.6 ± 11.5 h per week). Each player played two games during the CS:GO competition. The CS:GO tournament induced an increase in heart rate (HR), systolic blood pressure, and blood cortisol levels (C), and a decrease in the nonlinear heart rate variability (HRV) index based on the fractal correlation properties, called alpha1, of detrended fluctuation analysis (DFA-alpha1). In contrast, no changes were observed in blood levels of testosterone (T) and lactate (BLa). It was found that changes in physiological indices in players while playing CS:GO did not differentiate between winners and losers. The changes in the physiological parameters recorded during play indicate that CS:GO tournaments induce significant physiological arousal and can be considered a stressor.

Background: Endurance athletes (EA) are an emerging population of focus for cardiovascular health. The oxygen uptake efficiency plateau (OUEP) is the levelling-off period of ratio between oxygen uptake (VO₂) and ventilation (VE). In the cohort of EA, we externally validated prediction models for OUEP and derived with internal validation a new equation. Methods: 140 EA underwent a medical assessment and maximal cycling cardiopulmonary exercise test. Participants were 55% male (N = 77, age = 21.4 ± 4.8 years, BMI = 22.6 ± 1.7 kg·m^− 2, peak VO₂ = 4.40 ± 0.64 L·min^− 1) and 45% female (N = 63, age = 23.4 ± 4.3 years, BMI = 22.1 ± 1.6 kg·m^− 2, peak VO₂ = 3.21 ± 0.48 L·min^− 1). OUEP was defined as the highest 90-second continuous value of the ratio between VO₂ and VE. We used the multivariable stepwise linear regression to develop a new prediction equation for OUEP. Results: OUEP was 44.2 ± 4.2 mL·L^− 1 and 41.0 ± 4.8 mL·L^− 1 for males and females, respectively. In external validation, OUEP was comparable to directly measured and did not differ significantly. The prediction error for males was − 0.42 mL·L^− 1 (0.94%, p = 0.39), and for females was + 0.33 mL·L^− 1 (0.81%, p = 0.59). The developed new prediction equation was: 61.37–0.12·height (in cm) + 5.08 (for males). The developed model outperformed the previous. However, the equation explained up to 12.9% of the variance (R = 0.377, R² = 0.129, RMSE = 4.39 mL·L^− 1). Conclusion: OUEP is a stable and transferable cardiorespiratory index. OUEP is minimally affected by fitness level and demographic factors. The predicted OUEP provided promising but limited accuracy among EA. The derived new model is tailored for EA. OUEP could be used to stratify the cardiorespiratory response to exercise and guide training.

Respiratory muscle training (RMT) improves endurance performance, balance, and ability to repeat high-intensity exercise bouts, providing a rationale to be applied in short-track speedskating. To establish a preferable RMT method for short-track speedskating, the influence of inspiratory pressure threshold loading (IPTL) and voluntary isocapnic hyperpnoea (VIH) on cardiopulmonary indices and athletic performance was investigated. Sixteen elite short-track speedskaters completed 6 weeks of RMT based on IPTL or VIH. Wingate Anaerobic Tests (WAnTs), cardiopulmonary exercise tests (CPETs), spirometry assessments, and on-ice time trials were performed before and after RMT intervention. Repeated measures ANOVA was used to assess the differences between each method’s influence. No statistically significant (p > 0.05) differences between RMT methods were found in performance during the WAnT, CPET, or specific on-ice time trials. Spirometry measures were similar between both methods. Significant effects were found for the interaction between maximum breathing frequency during CPET (BFmax) and method (p = 0.009), as well as for the interaction between BFMax, method, and sex (p = 0.040). BFmax decreased for IPTL and increased for VIH. The interaction between method and sex revealed that BFmax increased only in males performing VIH. Our findings suggest that IPTL and VIH lead to analogous effects in the study participants, highlighting a negligible practical disparity in the impact of different RMT methods in elite short-track speedskaters.

Objective: The main objective of this study was to compare lactate thresholds and aerobic capacity from a graded-intensity exercise test (GXT) for near-infrared spectroscopy measurements in healthy, untrained individuals and highly trained athletes. Methods: This study included 29 untrained students (13 females) and 27 highly trained speed skaters (13 females). A maximal effort GXT was performed on a cycloergometer. The lactate-based aerobic and anaerobic thresholds, and the corresponding thresholds for muscle oxygen saturation (SmO₂), were determined. Results: The power values determined for all thresholds were significantly higher in female and male speed skaters compared to male and female college students. SmO₂ at anaerobic thresholds was significantly lower in female speed skaters than in female students. Both female and male skaters showed greater changes in SmO₂ after the GXT compared to students. The recovery did not significantly differ between groups within gender. There was a significant positive correlation in females between the rate of muscle reoxygenation and VO₂max power (r = 0.610). In speed skaters, the rate of muscle reoxygenation was not significantly higher than students and correlated positively with VO₂max (r = 0.449). Conclusions: The SmO₂ at the exercise thresholds, during and after maximal exercise, depends on the training status of the individual. The participants with a higher physical fitness level showed greater decreases in ΔSmO₂ at the AT level, as well as after maximal exercise. SmO₂ corresponding to the well-established exercise thresholds may be applied to guide training prescription. The rate of muscle reoxygenation after a GXT was also dependent on the aerobic capacity of the participants.

Background/Objectives: As short-track speed skaters have to race multiple races to achieve success during competition, optimizing the recovery between efforts is a noteworthy performance determinant. Therefore, we compared three different recovery modalities (active cycling recovery, pneumatic compression boots, and isocapnic breathing protocol) in the context of perceived subjective pain and recovery variables, multiple biochemical and biomechanical indices, CMJ height and power, as well as repeated efforts on the ice track. Methods: Fifteen elite short-track speed skaters (eight males and seven females; age 18.3 ± 1.0 years, height 175.6 ± 7.5 cm, weight 73.7 ± 7.7 kg, 23.8 kg/m², VO₂max 55.5 mL·kg⁻¹·min⁻¹: ♂ 58 20 ± 3.6 mL·kg⁻¹·min⁻¹; and ♀ 53 ± 4.5 mL·kg⁻¹·min⁻¹) completed the study experiment and were included in the analyses. Repeated measures ANOVA with optional post hoc Bonferroni correction was used to assess the association magnitude of changes in variables across the recovery methods. Results: All the investigated protocols were associated with significant changes in multiple recovery indices observed within all the investigated protocols (p ≤ 0.05). However, for this sample, they resulted in analogous effects on subjective variables, hormonal response, creatine kinase, CMJ parameters, and on-ice performance (between-protocol effect: p ≥ 0.002). Changes in creatine kinase were generally higher in males than females (p = 0.05), which might suggest that optimal recovery protocols in short-track are gender-dependent. Conclusions: Since compression and active cycling remain gold standard recovery protocols, a similar response from isocapnic breathing suggests it may be a modality particularly useful in real-world settings.