Recent evidence indicates that elevating plasma nitrites through dietary nitrates (NO3−) supplementation is associated with enhanced muscle efficiency, fatigue resistance and performance. Beetroot (in various forms) is the dominant source of dietary NO3− primarily due to its vast availability and the simple form of preparation suitable for final consumption. After a few years of research and experimentation, our scientific team identified alternative source rich with dietary NO3− as possible nitric oxide precursor, amaranth (Amaranthus hypochondriacus) with a standardized concentration 9–11% of NO3−. This study aimed to evaluate the effect of single-dose (±400 mg of dietary NO3−) and long-term (6 days) supplementation of amaranth concentrate derived dietary NO3− on aerobic capacity in physically active young people. We conducted a randomized, double-blind, placebo-controlled human study. Thirteen healthy and physically active young male participants were randomized into experimental and placebo groups. The aerobic capacity was tested during increasing cycling exercise (ICE) with pulmonary gas exchange recording and analysis. The peak power of the ICE, the maximum oxygen consumption and the first ventilatory threshold were significantly increased after long-term consumption of dietary amaranth (from 4.44 ± 0.50 to 4.55 ± 0.43 W/kg; from 37.7 ± 2.7 to 41.2 ± 5.4 mL/kg/min and from 178.6 ± 30.3 to 188.6 ± 35.2 W, p < 0.05; respectively) in experimental group. Long-term (6 days) use of dietary NO3− from amaranth may improve the aerobic capacity during ICE in young physically active male persons. It can be recommended as the nutritional supplement during last week of preparation for competition in endurance events.

The effect of deep mineral water (DMW) with moderate mineralization on the recovery of physical performance after prolonged dehydrating aerobic exercise in the heat was studied in nine healthy, physically active (VO2max = 45.8 ± 8.4 mL kg−1 min−1) women aged 24.0 ± 3.7 years.

While anaerobic fitness is highly important for the performance in Olympic (amateur) boxing, the relationship between anaerobic performance metrics is poorly understood, and profiling boxers according to their anaerobic capacity is still a challenge. With the current study in elite amateur boxers, we aimed to compare the metabolic and cardiovascular responses to different maximal tests and the intercorrelations between performance indices (peak and mean power, duration of the test, punching frequency) of several all-out tests and their correlation to physiological response metrics (blood lactate and heart rate, HR). Twelve male Olympic boxers performed a battery of tests, including 30 s Wingate cycling and arm cranking, boxing bag punching, steep uphill treadmill running to exhaustion, and progressive treadmill running VO₂max test. Performance indices of different anaerobic tests were not closely correlated except for the duration of uphill running with body weight scaled (relative) peak and mean power produced during Wingate cycling test and absolute mean power of both Wingate tests. The number of punches landed on a bag per 30 s was associated only with relative power achieved during Wingate cycling test. HRpeak but not peak lactate response correlated strongly across exercise tasks. Finally, no correlation between the highly developed aerobic and anaerobic capacity, suggests a complex picture of the adaptation in elite amateur boxers.

Background: Blood volume (BV), haemoglobin mass (Hb-mass) are key determinants of blood oxygen transport. The aim of this study was to assess BV and Hb-mass in elite junior rowers and evaluate their relationship with fat-free mass (FFM) and aerobic capacity. Methods: Twenty-five males (18.4 ± 2.4 y, 1.92 ± 0.5 m, 89.3 ± 4.7 kg) and fourteen females (17.0 ± 1.9 y, 1.77 ± 0.7 m, 74.2 ± 11.3 kg) participated. BV, plasma volume (PV), and Hb-mass were assessed via CO rebreathing. Pulmonary gas exchange was measured during a graded rowing test. Results: Males had higher absolute BV (7270 ± 717 vs. 5388 ± 471 mL) and Hb-mass (1083 ± 91 vs. 720 ± 49 g). After adjusting for FFM, most differences disappeared, except PV, which remained higher in females (57.2 ± 4.8 vs. 49.9 ± 6.5 mL·FFM·kg⁻¹). V̇O₂max was higher in males in absolute (6.28 ± 0.40 vs. 4.48 ± 0.29 L·min⁻¹) and body-mass-relative terms (70.2 ± 5.6 vs. 61.3 ± 7.3 mL·kg⁻¹·min⁻¹), but not when expressed per FFM (79.4 ± 5.3 vs. 81.1 ± 7.3 mL·FFM·kg⁻¹·min⁻¹). BV, PV, and Hb-mass correlated positively with V̇O₂max in both sexes, with stronger associations in females. Conclusions: Sex differences in blood parameters among junior rowers are largely explained by FFM, except for PV, which is relatively higher in females. Stronger associations between blood variables and aerobic capacity in females suggest greater reliance on central oxygen transport.

Over the past five years, the popularity of dietary nitrates as an ergogenic device among athletes has increased significantly. Hypoxic and acidic conditions that occur during exercise facilitate the conversion of nitrite to nitric oxide (NO) and increase the physiological efficiency of exogenously produced nitrite. After a few years of our team predicted experiments, as a nitric oxide precursor, amaranth (Amaranthus hypochondriacus) was identified as a source of dietary nitrates (concentrations 9-11%). The aim of this study was to evaluate the effect of single-dose and long- term doses of dietary nitrates from amaranth concentrate on the aerobic capacity of physically active young persons. Thirteen healthy and physically active young participants were randomized to experimental and placebo groups using a increasing cycling exercise (ICE) and placebo- controlled design. Pulmonary gas exchange recording (oxygen uptake (VO 2 ), pulmonary ventilation (VE), respiratory exchange ratio (RER)) and analysis of blood lactate samples were obtained. Our findings indicate that the single dose of dietary amaranth (400 mg) significantly improved only the power of the test performance. Long-term (6 days) intake significantly increased the power of the test performance, the maximum oxygen consumption and the power of the test for the first ventilation threshold value (from 37.7±2.7 mL/kg/min during the first test to 41.2±5.4 mL/kg/min during the third test, p <0.05).

Background: Dynamic change of the pulmonary oxygen uptake is one of the core parameters determining the bodies’ adaptability to the varying physical load. It is equally important in both everyday life and sports. Regardless of the importance, this physiological mechanism is understudied, especially in younger population. Therefore, the aim of this study was to examine oxygen uptake kinetics at the onset and offset of exercise in terms of basketball training and maturity level in adolescent boys. Methods: Our subjects were 28 basketball-trained (BT) and 22 actively untrained (UT) boys (average age: 11.83 ± 0.43 years). Subjects performed 6-minute-long constant speed walking tests on a treadmill and a static recovery afterwards with a 1-year interval between the sessions to determine oxygen uptake, heart rate, and muscle oxygenation time constants and other parameters. Maturity level was determined by the maturity offset. Results: Basketball-trained group showed faster oxygen uptake kinetics (1st session: 13.10 ± 2.68 s and 15.02 ± 2.96 s in basketballers and control-group boys, respectively; 2nd session: 12.02 ± 2.86 s and 14.07 ± 4.18 s) during both testing sessions, while heart rate kinetics were faster in basketballers only during the 1st session (28.15 ± 10.59 s compared to 37.18 ± 15.23 s). Maturity level in both groups correlated with some of the kinetics parameters during the 2nd session. Conclusion: Young basketballers possess a faster on-transient oxygen uptake kinetics compared to their untrained peers because of the improved oxygen delivery and utilisation. A possible maturational threshold regarding pulmonary oxygen uptake kinetics in adolescents should be investigated in the future. Keywords: team sports, physical fitness, time constant, aerobic kinetics