scholarly journals Influence of Running Phases on the Postural Balance of Modern Pentathlon Athletes in a Laser Run Event

Author(s):  
Sadowska ◽  
Lichota ◽  
Sacewicz ◽  
Krzepota

Background: The Laser Run combined event is part of the modern pentathlon, consisting of successive shooting and running phases. The main factor hindering accurate and fast shooting is the increasing fatigue caused by running effort. The aim of this study was to assess the impact of the running phases on the postural balance in the shooting position of pentathletes in a Laser Run event. Methods: 25 modern pentathletes (18.6 ± 1.7 years), members of the Polish Association of Modern Pentathlon, completed a Laser Run event. During each shooting series, a Zebris dynamometric platform recorded the displacement of the centre of pressure (COP). Results: Significant changes in the average velocity of the COP (F = 3.43; p = 0.0223) and the width of the ellipse of the COP shifts area WoE (F = 3.30; p = 0.0259) between the first and the second shooting series were observed. The average velocity of the COP in series I was 72.6 m/s and increased to 84.3 m/s in series II. In turn, the average width of the ellipse of the COP in series I reached 29.1 mm and in series II, 34.1 mm. Conclusions: The fatigue caused by the running phases in the Laser Run affects the stability of the shooting position of pentathletes. Disturbances that occur after the first running phase are maintained at the same level during the subsequent shooting series. The fatigue level does not affect the magnitude of the disturbances of the postural balance in the shooting position.

Author(s):  
Dorota Sadowska ◽  
Tomasz Sacewicz ◽  
Małgorzata Lichota ◽  
Justyna Krzepota ◽  
Maria Ładyga

Postural balance is a key element of shooting effectiveness, which determines the outcome of modern pentathlon competitions. The aim of the study is to examine the postural balance of 27 pentathletes (12 females and 15 males; mean age: 18.0 ± 1.8 years), and 26 physically active, untrained subjects (12 females and 14 males; mean age: 22.5 ± 1.4 years), and to investigate the impact of footwear on the stability of the shooting position in pentathletes. Methods: Static postural balance was examined during quiet stance in four test conditions (standing in footwear with eyes opened, standing in footwear with eyes closed, standing barefoot with eyes opened, and standing barefoot with eyes closed). During each postural balance measurement, the participant remained still on the platform, with their arms in front of their body. Postural balance in the shooting position was only evaluated in the group of pentathletes. The athlete was asked to assume a comfortable shooting position on the platform and to aim at the target. Standard pentathlon targets and pistols were used in the study. Measurements were carried out twice (barefoot and in footwear). Results: In all conditions, pentathletes achieved lower values of posturographic measures than in the control group. In non-visual conditions, measures describing the surface area of the centre of pressure decreased in pentathletes and increased in the control group. Both pentathletes and non-athletes were equally stable barefoot as in footwear. Footwear did not affect postural sway in the shooting position in pentathletes. Conclusions: Pentathletes were found to have significantly better stance stability and were less vision-dependent in postural balance than untrained subjects. Bearing in mind that the shooting position of pentathletes was as stable barefoot as in footwear, the main factors which were most likely responsible for minimising body oscillations in the pentathletes were their high level of concentration and conscious control of body alignment.


2022 ◽  
pp. 126-137
Author(s):  
M. A. Kashina ◽  
V. R. Popov

The relevance of this research is about the need to search for factors that increase the stability of youth associations, including student ones. Only stable youth associations can effectively socialize young people and form them as active actors in civil society. The project is a desk study and has a quality design.Object: non-university mass student public associations. They were created in Russia in the 60s of the twentieth century: student building brigades (SSO) and student nature protective brigades (DOP). Subject: institutional isomorphism of non-university student public associations. Purpose: to assess the impact of character and the degree of isomorphism of student public associations on their stability.Research results. It is shown that the main factor in the stability of student public associations is the level of their compliance with institutional requirements. It leads to forced isomorphism. The cause of this isomorphism is the monopoly of sources of support for the activities of these associations. In Russia, the state has such a monopoly. Student associations must take into account the institutional factors, in particular the requirements of higher-level systems and institutions. It gives them the necessary resources to continue their activities. Intra-organizational factors (level of social significance, charisma of leaders, mass character, and others) are less important for ensuring their sustainability.


1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.


Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.


2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cui Wang ◽  
Ling Cai ◽  
Yaojian Wu ◽  
Yurong Ouyang

AbstractIntegrated renovation projects are important for marine ecological environment protection. Three-dimensional hydrodynamics and water quality models are developed for the Maowei Sea to assess the hydrodynamic environment base on the MIKE3 software with high resolution meshes. The results showed that the flow velocity changed minimally after the project, decreasing by approximately 0.12 m/s in the east of the Maowei Sea area and increasing by approximately 0.01 m/s in the northeast of the Shajing Port. The decrease in tidal prism (~ 2.66 × 106 m3) was attributed to land reclamation, and accounted for just 0.86% of the pre-project level. The water exchange half-life increased by approximately 1 day, implying a slightly reduced water exchange capacity. Siltation occurred mainly in the reclamation and dredging areas, amounting to back-silting of approximately 2 cm/year. Reclamation project is the main factor causing the decrease of tidal volume and weakening the hydrodynamics in Maowei Sea. Adaptive management is necessary for such a comprehensive regulation project. According to the result, we suggest that reclamation works should strictly prohibit and dredging schemes should optimize in the subsequent regulation works.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2838
Author(s):  
Xiaoxing Zhang ◽  
Haoyuan Yi ◽  
Junjun Liu ◽  
Qi Li ◽  
Xin Luo

There has been a rising interest in compliant legged locomotion to improve the adaptability and energy efficiency of robots. However, few approaches can be generalized to soft ground due to the lack of consideration of the ground surface. When a robot locomotes on soft ground, the elastic robot legs and compressible ground surface are connected in series. The combined compliance of the leg and surface determines the natural dynamics of the whole system and affects the stability and efficiency of the robot. This paper proposes a bio-inspired leg compliance planning and implementation method with consideration of the ground surface. The ground stiffness is estimated based on analysis of ground reaction forces in the frequency domain, and the leg compliance is actively regulated during locomotion, adapting them to achieve harmonic oscillation. The leg compliance is planned on the condition of resonant movement which agrees with natural dynamics and facilitates rhythmicity and efficiency. The proposed method has been implemented on a hydraulic quadruped robot. The simulations and experimental results verified the effectiveness of our method.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2301
Author(s):  
Man Zhang ◽  
Bin Liang ◽  
Hongjun He ◽  
Changjian Ji ◽  
Tingting Cui ◽  
...  

Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
Ji Young Yu ◽  
Piyanan Chuesiang ◽  
Gye Hwa Shin ◽  
Hyun Jin Park

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.


2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Shuai Yang ◽  
Haijun Jiang ◽  
Cheng Hu ◽  
Juan Yu ◽  
Jiarong Li

Abstract In this paper, a novel rumor-spreading model is proposed under bilingual environment and heterogenous networks, which considers that exposures may be converted to spreaders or stiflers at a set rate. Firstly, the nonnegativity and boundedness of the solution for rumor-spreading model are proved by reductio ad absurdum. Secondly, both the basic reproduction number and the stability of the rumor-free equilibrium are systematically discussed. Whereafter, the global stability of rumor-prevailing equilibrium is explored by utilizing Lyapunov method and LaSalle’s invariance principle. Finally, the sensitivity analysis and the numerical simulation are respectively presented to analyze the impact of model parameters and illustrate the validity of theoretical results.


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