Relationship between Isokinetic Knee Strength and Speed, Agility, and Explosive Power in Elite Soccer Players

The aim of this study was to determine the relationship between the isokinetic characteristics of knee extensors and flexors with selected motor abilities: Speed, agility, and explosive power of lower extremities of professional football players in the preparation period of a yearly training cycle. Twenty-one players (age: 24.5 ± 3.9 years; body mass: 76.7 ± 4.7 kg and body height: 183.5 ± 5.5 cm) playing in the highest Polish soccer league participated in the study. The isokinetic concentric torque of the knee extensors and flexors was measured at 300°/s, 180°/s, and 60°/s velocities. Sprint performance was assessed in the 30 m sprint test (standing start). The forward, lateral, and backward movements were assessed using the T-Test of agility. Explosive power was quantified by performing the squat jump (SJ) and countermovement (CMJ), using the force platform. Due to sport-specific demands of soccer activities measured in this experiment, the relationships between peak torque (PT) and the 30 m sprint, T-Test of agility, and power of vertical jumps (SJ and CMJ) were low or medium at speeds of 60°/s and 300°/s. One of the main reasons for the lack of high dependence of the above-mentioned factors are that the measurements were performed during the initial training period where the level of individual abilities is at a low level. Additionally, this experiment may also indicate that the measurement of isokinetic knee flexion and extension peak is effective when performed at the correct angular velocity in relation to the evaluation of the intended motion structure.

Self-Esteem, Individual versus Team Sports

On the basis of the integrative concept of self-esteem discussed in sport-related literature, various studies refer to its importance in the context of sports activities. Self-esteem is often understood as a personality trait because it tends to be durable and stable. No accurate description is available regarding the types of sports in which subjects participated. The main purpose of the research was to identify and compare the levels of self-esteem and self-confidence of athletes practicing individual and team sports. The self-esteem and self-confidence levels were measured by the Rosenberg Self-Esteem Scale (Rosenberg 1979) and the Self-Confidence Test (Romek, 2000). All participants were males. Subjects were divided into two categories: 40 for individual sports and 40 for team sports. There were two evaluation periods: P1, the beginning of the preparation period, and P2, the beginning of the competition period. There were statistically significant differences for P1 (p < 0.002) and P2 (p < 0.003). The differences between the average values of the two periods were 5.8 points and 3.8 points, both favorable to the group of athletes who practiced individual sports. There were significant differences between the individual and team athletes in self-esteem level. Individual athletes presented a higher level of self-esteem.

SELECTED ASPECTS OF COMPILING A TWO-LANGUAGE GLOSSARY DEVOTED TO THE TOPIC «DRUG-RELATED CRIMES»

В статье рассмотрены лингвистические аспекты и дидактические возможности организации работы над составлением англо-русского глоссария по теме «Преступления, связанные с наркотиками», а также предложены варианты заданий, которые можно использовать как на практических занятиях по дисциплине «Иностранный язык», так и во время самоподготовки курсантов для совершенствования их иноязычной профессиональной коммуникативной компетенции. he article elicits linguistic aspects and didactic possibilities of organizing work at compiling an english-russian glossary on the topic «Drug-related crimes», and offers versions of tasks which can be used both in tutorials in «Foreign language» and during the preparation period of cadets to foster their foreign language professional communicative competence.

Volume/shear work ratio influence on wear and stress of soil chisel tine modelled by DEM

Agricultural equipment is working in very high-stress conditions. However, it has a significant influence on the wear losses of soil processing parts. Chisel is operating at 30 cm working depth at a maximum of 12 km·h−1 working speed. Due to unpredictable soil conditions, chisel tines suffer high wear losses. It leads to time consumption and cost expenses during the soil preparation period. Wear resistance, and agronomical requirements (working depth, loosening of soil) are the main criteria of agricultural equipment producers. The discrete element method is a solution that simulates soil as sphere shape particles with soil properties. Wear results reveal the change of parts shape, acting forces, and stresses during the simulation in the virtual soil bin. The used Rocky DEM software uses a parameter C (volume/shear work ratio) to describe wear intensity, which varies for different geometry. Chisel tine geometry should be divided into sections with varied parameter C according to stress acting on the surface. The test conditions can be used for future wear analysis of varied tool geometry and protection (sintered tungsten carbide plates, hard-faced surface, etc.) agricultural tools to compare its durability in different soil conditions.

LANDMARKS OF RUSSIA’S USE OF INFORMATION WARFARE

Russian Information warfare represents an extended concept that covers a wider and more diverse range of actions when compared to NATO's approach on information operations. Russian techniques, tactics and procedures in the field of information warfare do not differ much from those used in the Soviet period but are adapted to the new technological achievements. The specific means of use the information warfare are acquired by the future politico-military leaders of the Russian state starting with their preparation period at an age of accumulation. On short and medium term, it is likely that Moscow’s activities specific to the information warfare will increase being favored by the limitations imposed by the Covid 19 pandemic.

Planificación dietético-nutricional para una prueba de mountain bike de XCO: estudio de caso (Nutritional planning for an XCO mountain bike event: Case study)

El cross country es una modalidad del ciclismo de mountain bike (MTB), cuyas competiciones se caracterizan por dar un determinado número de vueltas a un circuito con una distancia desde 6-9km hasta 40-200km. En estos eventos, es importante planificar una estrategia dietético-nutricional para mitigar la aparición de resultados adversos relacionados con la nutrición. El objetivo de este estudio fue realizar la planificación dietético-nutricional de un ciclista de MTB que disputa una competición de cross country. El ciclista es un varón de 27 años (VO2max=74.46 ml•kg-1•min-1; PAM=420W; altura=1.81m; peso=78.6kg; % masa grasa=9.47, sumatorio de pliegues=61.9mm) con 3 años de experiencia en el entrenamiento y competición de pruebas MTB a nivel regional. La intervención tuvo lugar en el gabinete Alinua de la Universidad de Alicante, cuya finalidad fue mejorar la composición corporal y elaborar una programación dietético-nutricional para disputar una carrera de MTB el 23-2-2020 en la provincia de Alicante. La intervención incluía las recomendaciones para deportistas de resistencia y se dividió en un periodo de preparación, periodo de 3 semanas previas a la carrera y periodo competitivo. El participante realizó satisfactoriamente la prueba, se adhirió a la planificación, y no manifestó ningún problema. Para un ciclista, afrontar un evento de estas características con éxito requiere de un asesoramiento teórico-práctico y una programación dietético-nutricional de manera individualizada que trate de contribuir nutricionalmente antes, durante y después de la práctica del ejercicio, así como aminorar la posible aparición de contratiempos que puedan poner en riesgo el rendimiento y la salud. Abstract. Cross Country is a modality of mountain bike cycling (MTB), whose competitions are characterized by giving a certain number of laps to a circuit with a distance from 6-9km to 40-200km. In these events, it is important to plan a dietetic-nutritional strategy to mitigate the appearance of nutrition-related adverse outcomes. The purpose of the study was to plan the dietetic-nutritional planning of a MTB cyclist who competes in a Cross Country competition. The cyclist is a 27-year-old male (VO2max=74.46 ml•kg-1•min-1; MAP=420W; height=1.81m; weight=78.6kg; % fat mass=9.47; sum of 8 skinfolds=61.9mm) with 3 years of experience in training and competing in MTB events at a regional level. The intervention took place in the Alinua cabinet of the University of Alicante, whose purpose was to improve the body composition and to elaborate a dietetic-nutritional program to dispute a MTB race on 23-2-2020 in the province of Alicante. The intervention included the recommendations for endurance athletes and was divided into a preparation period, a period of 3 weeks before the race and a competitive period. Finally, the participant successfully completed the race according to the planning and did not manifest any problems. For a cyclist, facing an event of these characteristics successfully requires theoretical-practical advice and dietary-nutritional programming in an individualized way that tries to contribute at a nutritional level before, during and after physical exercise, as well as to reduce the possible appearance of setbacks that may jeopardize performance and health.

Metabolic Power, Active Drag, Mechanical and Propelling Efficiency of Elite Swimmers at 100 Meter Events in Different Competitive Swimming Techniques

Eight elite swimmers—four females and four males—were studied, each of whom specialized in different swimming techniques and ranked among the top 10 in the world in the 100 m event in their swimming specialty. Methods included a complex of physiological, biomechanical and hydrodynamic procedures, as well as mathematical modeling. During the special preparation period for the 2017 Swimming World Championship, all subjects performed an 8 × 100 m swimming step-test using their main swimming technique. The relationships between velocity, mechanical and metabolic power were obtained and analyzed for each swimming technique. It was found that, at the last stage of the test, in all swimming techniques, men demonstrated higher values of metabolic power (Pai = 3346–3560 W) and higher mechanical efficiency (eg = 0.062–0.068) than women (Pai = 2248–2575 W; eg = 0.049–0.052). As for propelling efficiency, women (ep = 0.67–0.71) and men (ep = 0.65–0.71) did not differ from each other. Results showed that the frontal component of active drag force is the main reason for the existing differences in maximal swimming velocity between different techniques, since no relevant differences were observed for mechanical and propelling efficiencies among swimming techniques.

HOW DOES THE G20 SUMMIT AFFECT LAND MARKET? EVIDENCE FROM CHINA

We employ the difference-in-difference and synthetic control methods to investigate the capitalization effect of hosting the G20 Summit on land market, based on China’s land transaction dataset from 2011 to 2019. We find that hosting the G20 Summit has a significant positive effect on land prices in the host city, increasing land prices by over 22.6% compared to comparable cities. The impact of hosting the G20 Summit on land prices is larger in the post-G20 period than in the preparation period. Further, hosting the G20 Summit has heterogeneous and distributional effects on land prices. The capitalization effects of venue construction and transportation infrastructure upgrading on land prices are the main channels.