Low-intensity exercise with blood flow restriction (LI BFR) has been shown to release substances that play a key role in neuroplasticity and may be effective in improving rehabilitation outcomes in patients with neurodegenerative diseases. Researchers suggest that LI BFR engages high-threshold motor units even during low-intensity exercise, leading to increased motor unit end-state variability and a rapid onset of neuromuscular fatigue. However, the amplitude-frequency characteristics and motor unit recruitment strategies during LI BFR are not well understood. The aim of this study was to investigate the effects of blood flow restriction on motor unit activation patterns during low-intensity exercise to elucidate the physiological mechanisms underlying this novel training approach. Participants with a mean age of 33 years were subjected to blood flow restriction during isometric wrist flexion. High-density surface EMG (HD sEMG) activity was recorded from both the flexor carpi radialis and palmaris longus muscles. The study shows that blood flow restriction significantly shifted motor unit activation to high threshold motor units. These findings highlight the need to investigate the long-term effects of LI BFR on motor unit coordination in clinical populations.

Dynamic postural stability depends on the integration of sensory inputs, neuromuscular control, and biomechanical stability. The quadriceps femoris muscle plays a crucial role in this process, providing knee joint extension and stability. This study aims to assess the influence of the peak isokinetic torque of the quadriceps femoris on postural balance under varying sensory conditions, while also considering the participants' cognitive style. The study involved 50 participants aged 25–69 years old. Postural stability was assessed using stabilography on hard and compliant surfaces, with eyes open and closed. Analysis included calculation of frequency-domain parameters that characterize the contribution of different sensory systems to body stability, as well as measurement of center of pressure velocity. The results showed significant negative correlations between the peak torque of the quadriceps femoris muscle and the velocity of the center of pressure shift (r ≤ -0.5, p ≤ 0.05 on a hard surface; r ≤ -0.6, p ≤ 0.05 with eyes closed). On a soft surface with eyes closed, the velocity of the center of pressure shift was 19–32 mm/s in field-dependent and 16–25 mm/s in field-independent participants. Participants with a field-dependent cognitive style demonstrated a higher velocity of the center of pressure shift in all testing conditions. Conclusions: Quadriceps femoris muscle strength makes a significant contribution to dynamic postural stability, predominantly in individuals with a field-independent sensory strategy.

Purpose : This study aims to analyze body composition, anthropometry, and physical activity among adolescent esports players aged 12–17 years and compare these parameters with the local population data for adolescents in their respective age groups. Method : A comprehensive study was conducted using height and weight measurements, bioimpedance analysis, and a questionnaire voluntarily and anonymously completed by adolescents within the specified age range. Results : Body mass index data revealed that 19.6% of all adolescents were overweight, and 17.6% were classified as obese. Bioimpedance analysis indicated that 39.1% of adolescents had a high percentage of body fat. Thirty-five point three percent of participants had a skeletal muscle index below the 25th percentile, 50.9% had a body fat percentage above the 75th percentile, and 52.9% had a phase angle below the 25th percentile observed for their respective age group population. Furthermore, we found that 90% of subjects did not meet the World Health Organization recommended daily physical activity. Conclusion : This study helped to identify the problem related to the physical condition of adolescent esports players aged 12–17 years, which may indicate potential health risks in the future. We encourage those involved with adolescent esports players to focus on healthy physical education. The esports community should prioritize evidence-based practices that promote physical activity for the well-being of adolescents.

A methodology for determining maximal anaerobic power and optimal pedaling cadence in sprint cyclists is presented, which is a key factor in track cycling performance. The study examines the impact of pedaling cadence on performance and emphasizes the importance of gear ratio selection for sprints. The research involved 10 professional sprint cyclists aged 15–19 years. Participants performed three maximal sprints with increasing resistance on a cycle ergometer equipped with an electronic braking system and sensors for precise measurement of left and right leg forces and pedaling cadence. This setup enabled the recording of force–cadence and power–cadence relationships. Data analysis was conducted using linear and quadratic regressions. Morphological assessments were conducted, including calculations of fat and muscle mass percentages using anthropometric methods. The study revealed significant interindividual differences in key performance parameters. Maximal power was achieved at an individual-specific optimal cadence, which varied by 20–40 %. The results validate the effec-tiveness of the proposed methodology for tailoring training processes to individual needs. The power–cadence relationship facilitates the determination of the optimal cadence at which max-imal power is attained. The findings underscore that adjusting the gear ratio to achieve the optimal pedaling cadence during sprints enables maximum performance and optimizes effort distribution during critical moments of track competition. The methodology provides tools for analyzing fatigue and other factors affecting performance. It enables precise evaluation of track cyclists' physical capabilities, optimizes training plans, enhances outcomes, and supports personalized tactical strategies, making it valuable for coaches and researchers in biomechanics and sports physiology.

Представлена методология, направленная на определение максимальной анаэробной мощности и оптимальной частоты педалирования у спринтеров, что является ключевым аспектом в трековом велоспорте. Обсуждается влияние частоты педалирования на производительность спортсменов и значимость выбора передаточного числа на результативность в спринте. В исследовании участвовали 10 профессиональных велосипедистов спринтеров в возрасте 15–19 лет. Участники исследования выполняли три максимальных ускорения с возрастающим сопротивлением на велоэргометре с электронным тормозным устройством и датчиками для высокоточного измерения силы правой и левой ног и частоты педалирования, что позволяло фиксировать зависимости «сила – частота педалирования» и «мощность – частота педалирования». Анализ данных проводили с использованием линейной и квадратичной регрессий. Дополнительно проводилось морфологическое обследование участников, включая расчет жировой и мышечной массы с использованием антропометрических методов. Исследование выявило значительные различия в ключевых параметрах между спортсменами. Максимальная мощность достигалась при индивидуально специфической частоте педалирования, которая варьировалась в пределах 20–40 %. Результаты исследования подтверждают эффективность предложенной методики для индивидуальной настройки тренировочного процесса. Использование зависимости «мощность – частота педалирования» позволяет определить оптимальную частоту педалирования, при которой спортсмен достигает максимальной мощности. Полученные зависимости демонстрируют, что индивидуальная настройка передаточного числа для проявления в ускорениях оптимальной частоты педалирования позволяет достигать максимальной производительности и оптимизировать распределение усилий в ключевые моменты соревнований. Методика также предоставляет инструменты для анализа влияния усталости и других переменных на производительность спортсменов. Предложенная методология оценки биомеханических характеристик спринта на велоэргометре предоставляет возможность высокоточной оценки физических возможностей спортсменов спринтеров на треке. Ее применение в тренировочном процессе способствует оптимизации планирования тренировок, улучшению спортивных результатов и созданию персонализированных тактических решений. Методика представляет значительный интерес для тренеров и исследователей, занимающихся изучением механики движений и спортивной физиологией.

This study investigated neuromuscular activation strategies in individuals with different training backgrounds during isometric contractions of the knee extensor muscles (m. vastus lateralis) during moderate-intensity contractions (≤30% of maximal voluntary contraction, MVC) with progressively increasing load. Untrained (n = 18) and trained participants (n = 14) were compared. Muscle activity was recorded using high-density surface electromyography (HD-sEMG) during testing on an IsoMed 2000 isokinetic dynamometer, followed by signal decomposition and extraction of motor unit (MU) activation patterns. Analysis revealed differences in muscle activation strategies between groups: trained participants demonstrated a more economical MU recruitment strategy and more pronounced increases in MU discharge frequency and amplitude with rising load. The findings indicate that the greater efficiency of force generation in trained individuals is determined not only by higher absolute strength but also by functional adaptations in MU recruitment and discharge behavior. The results reflect specific neuromuscular adaptations formed in response to systematic strength training and may be useful for personalized assessment of the functional state of the neuromuscular system.