Effect of Knee Injury on Foot Load of Rugby Players

Předmětem této práce je statistické vyhodnocení získaných dat pedobarometrického měření a zjištění jejich možné souvislosti s bolestí kolen u hráčů ragby. Nasbíraná data byla hodnocena dle různých kritérií a byly zohledněny výpovědi dotazníků, které zahrnovaly specifika bolesti kolen a úrazovou historii hráčů. Kontrolní soubor představovala zdravá končetina každého hráče, s níž byly výsledky porovnávány. V teoretické části práce se pojednává o základních anatomických, kineziologických a biomechanických aspektech sledovaných kloubů. Tato část práce také ozřejmuje obecnou etiologii zranění kolen a příčinu vzniku úrazů i v ragby, jehož představení náleží prvním stránkám práce. Metodika práce charakterizuje testovaný soubor a jeho sportovní nároky. Specifikuje pravidla a postupy provedeného pedobarometrického měření. Speciální část se věnuje interpretaci zjištěných výsledků a jejich diskuzi. Ze zjištěných hodnot dominuje umístění bodu maximálního tlaku a rozložení předozadního zatížení během chůze i stoje. Bod největšího tlaku náleží bolavé končetině a stejně tak předozadní zatížení je na sledované končetině výraznější na přední části nohy. Diskuze práce hodnotí získané výsledky a porovnává je se zahraničními autory a již proběhlými studiemi.The aim of this thesis is a statistical evaluation of the data gained from a pedobarometrical analysis and discovering their possible connection with knee pain in rugby players. The collected data were evaluated on the basis of various criteria together with the replies to questionnaires which included the specifics of knee pain and the player's injury history. All the results were compared with control samples - the non-injured limb of each player. In the theoretical framework of the thesis I deal with the basic anatomical, kinesiological and biomechanical aspects of the monitored joints. This part also includes clarification of the general etiology of knee injuries and rugby injury causes, as described on the first pages of the thesis. The methodology of work characterises the tested file and its sport demands. It specifies the rules and procedures of the made pedobarometrical measuring. The interpretation of the results and their discussion is analyzed in a special part of the thesis. Plantar peak pressure location and anteroposterior load distribution during walking and standing dominate from all the measured values. Just as the plantar peak pressure appertains to the painful limb, the anteroposterior load distribution is more distinct at the front part of the leg. The obtained results and their comparison with foreign authors and studies are evaluated in the thesis discussion

Shell galaxies as laboratories for testing MOND

Tests of MOND in ellipticals are relatively rare because these galaxies often lack kinematic tracers in the regions where the MOND effects are significant. Stellar shells observed in many elliptical galaxies offer a promising way to constrain their gravitational field. Shells appear as glowing arcs around their host galaxy. They are observed up to ~100 kpc. The stars in axially symmetric shell systems move in nearly radial orbits. The radial distributions of shell locations and the spectra of stars in shells can be used to constrain the gravitational potential of their host galaxy. The symmetrical shell systems, being especially suitable for these studies, occur in approximately 3% of all early-type galaxies. Hence the shells substantially increase the number of ellipticals in which MOND can be tested up to large radii. In this paper, we review our work on shell galaxies in MOND. We summarize the paper B\'{i}lek et al. (2013), where we demonstrated the consistency of shell radii in an elliptical NGC 3923 with MOND, and the work B\'{i}lek et al. (2014), in which we predicted a giant (~200 kpc), as yet undiscovered shell of NGC 3923. We explain the shell identification method, which was used in these two papers. We further describe the expected shape of line profiles in shell spectra in MOND which is very special due to the direct relation of the gravitational field and baryonic matter distribution (B\'{i}lek et al., 2014, in preparation).Comment: 21 pages, 8 figures, 1 table, accepted for publication in the special MOND issue of the Canadian Journal of Physic

MOND implications for spectral line profiles of shell galaxies: shell formation history and mass-velocity scaling relations

Context. Many ellipticals are surrounded by round stellar shells probably stemming from minor mergers. A new method for constraining gravitational potential in elliptical galaxies has recently been suggested. It uses the spectral line profiles of these shells to measure the circular velocity at the edge of the shell and the expansion velocity of the shell itself. MOND is an alternative to the dark matter framework aiming to solve the missing mass problem. Aims. We study how the circular and expansion velocities behave in MOND for large shells. Methods. The asymptotic behavior for infinitely large shells is derived analytically. The applicability of the asymptotic results for finitely sized shells is studied numerically on a grid of galaxies modeled with S\'ersic spheres. Results. Circular velocity settles asymptotically at a value determined by the baryonic mass of the galaxy forming the baryonic Tully-Fisher relation known for disk galaxies. Shell expansion velocity also becomes asymptotically constant. The expansion velocities of large shells form a multibranched analogy to the baryonic Tully-Fisher relation, together with the galactic baryonic masses. For many - but not all - shell galaxies, the asymptotic values of these two types of velocities are reached under the effective radius. If MOND is assumed to work in ellipticals, then the shell spectra allow many details of the history to be revealed about the formation of the shell system, including its age. The results pertaining to circular velocities apply to all elliptical galaxies, not only those with shells.Comment: 8 pages, 7 figures, 1 table, accepted for publication in A&

Deep imaging of the shell elliptical galaxy NGC3923 with MegaCam

Context. The elliptical galaxy NGC 3923 is known to be surrounded by a number of stellar shells, probable remnants of an accreted galaxy. Despite its uniqueness, the deepest images of its outskirts come from the 1980s. On the basis of the modified Newtonian dynamics (MOND), it has recently been predicted that a new shell lies in this region. Aims. We obtain the deepest image ever of the galaxy, map the tidal features in it, and search for the predicted shell. Methods. The image of the galaxy was taken by the MegaCam camera at the Canada-France-Hawaii Telescope in the g' band. It reached the surface-brightness limit of 29 mag/arcsec2. In addition, we reanalyzed an archival HST image of the galaxy. Results. We detected up to 42 shells in NGC 3923. This is by far the highest number among all shell galaxies. We present the description of the shells and other tidal features in the galaxy. A probable progenitor of some of these features was discovered. The shell system likely originates from two or more progenitors. The predicted shell was not detected, but the new image revealed that the prediction was based on incorrect assumptions and poor data.Comment: 14 pages, 2 tables, 19 figures, accepted for publication in A&