Wyniki wyszukiwania - Biblioteka Nauki

1

Comparison of Ankle Taping and Bracing on Ankle Biomechanics during Landing in Functional Ankle Instability

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McKelle Ulm H. , Windsor B. , Dedrick G. , Powell D. W.

Central European Journal of Sport Sciences and Medicine

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2015

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tom 11

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nr 3

5-14

EN

Lateral ankle sprains are one of the most common injuries in athletics. Injury to lateral ankle ligaments can result in persistent instability of the ankle joint, known as functional ankle instability (FAI). Two methods of treating FAI are ankle taping and ankle bracing. The purpose of this study was to compare the effects of ankle taping and ankle bracing on ankle joint kinematics and kinetics during a landing task. Methods: Seven individuals with FAI and seven healthy controls performed three landing trials in each of three conditions: control, taped and braced. Ground reaction forces and three-dimensional kinematics were collected simultaneously while participants performed single-leg step-off landing trials from a box with a height of 0.6m. Peak ankle joint angles and moments were calculated using customized software. Results: Individuals with FAI produced significantly smaller inversion moments compared to healthy controls (p = 0.006). Ankle stabilization did not significantly alter ankle joint angles, ranges of motion or moments. Discussion: The present findings suggest that individuals with FAI exhibit unique ankle biomechanics independent of ankle stabilization modality. Future research may seek to investigate the multi-joint biomechanical adaptations associated with ankle stabilization in individuals with FAI compared to healthy controls.

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Dwa komentarze do Eurokodu 3 (PN-EN 1993-1-1:2005 + AC:2006) dotyczące zagadnień projektowych

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Ziółko J.

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2011

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tom z. 58, nr 3/I

289-300

PL

W referacie skomentowano zagadnienia materiałowe omówione w rozdziale 3 Eurokodu 3 oraz zwrócono uwagę na brak w tej normie zaleceń dotyczących stężeń międzywiązarowych w dachach budynków o stalowej konstrukcji nośnej. Podkreślono merytorycznie dobre ujęcie w Eurokodzie 3 zagadnień materiałowych, a zwłaszcza doboru stali na konstrukcje budowlane z uwzględnieniem odporności na kruche pękanie oraz pękanie lamelarne. Zaproponowano drobne uzupełnienie punktu 3.2.5 - Tolerancje. W omawianym Eurokodzie nie ma zaleceń dotyczących stężeń międzywiązarowych w dachach budynków stalowych. Jest to istotna usterka, która zdaniem autora, powinna być poprawiona przy nowelizacji obecnej wersji Eurokodu. Przytoczone w referacie katastrofy budowlane potwierdzają słuszność tego postulatu.

EN

Material issues described in Eurocode 3, Part 1-1, Section 3 are commented and a lack of information regarding vertical bracings in steel roof structures is indicated. Proper formulation of material requirements is remarked, particularly the steel grade selection for building structures with respect to brittle and lamellar fracture. A small supplement to Section 3.2.5 - Tolerances is proposed. There is no recommendation connected with vertical roofbracings in the Eurocode 3, Part 1-1. This is important lack, which in the author opinion, should be taken into account during the present amendment of the Eurocode. The structural failures presented in the paper prove the importance of this factor.

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Buckling of frame braced by linear elastic springs

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Iwicki P.

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2010

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tom Vol. 14, nr 2

201-213

EN

In the design codes and specifications, simplified formulae or diagrams are given for determining the buckling lengths of frame columns based on the ruling criterion of considering frames as sway or non sway. Due to the fact that, the code formulae utilize only local stiffness distributions, these formulae may yield in certain cases rather erroneous results. In most code formulas a case of weakly braced frames is usually not considered. In this paper the classical Winter model, developed originally for columns is applied for frame structures and compared with the results of parametric study of frame with bracing. Sensitivity analysis of critical loads of frame due to bracing stiffness variations is carried out and the method for calculation of the threshold bracing stiffness condition for frames is proposed.

4

Sztywność budynku ze stężeniami o różnej konfiguracji

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Kędzior K. , Kozłowski A.

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tom z. 58, nr 1

191-202

EN

One of the most often used bracing system in multi-storey buildings is truss system. In this system horizontal loading is transmitted by stiff floor plates to the vertical bracings, located in selected planes. Vertical bracing truss was designed as cantilever fIxed in foundation. Traditionally, vertical truss was composed of member located in one tract, i.e. each bracing fIeld placed above previous one. In many practical cases, mainly because of functional reasons, it is a need to change location of selected bracing members. The aim of the paper is to investigate how various bracing confIguration influence steel skeleton members exertion and overall stiffness of building. Analysis was conducted on three frames types: two-, fIve-, and twelve-storey. Each of them was analyzed as plane as well as space frame, altogether 29 frames were calculated. It was concluded that non-conventional bracing location leads to decreasing of frame lateral drift, while do not change essentially members exertion.