Vergleich von Körperschwerpunkt-Flugbahnen in modernen Riesenslalom-Techniken

An analysis was made of the possibility of executing modern giant-slalom technique variants, and the differences between them, on a sample of seven elite athletes in a simplified competitive situation. The analysis of the selected runs showed that all the athletes were able to perform the turns in given conditions with both giant-slalom techniques – the technique with velocity control and the technique with velocity increase. The analysis of kinematic parameters was limited to the centre of mass (CM) trajectories. The differences were tested with a Student’s t-test for dependent samples. Statistically significant differences were obtained between the two skiing techniques in the athletes’ CM trajectories in the measured area (second and third turns). This fact, together with other proven differences between the trajectories of both techniques, mostly contributed to the confirmation of the advantage of skiing with the technique with velocity increase and the realization of the theoretical and practical background of this study.Uvod Moderna skijaška vožnja između vrata spaja pojedinačne elemente sijaškog zavoja u jedinstveno kretanje, pa ih je vrlo teško, barem u praksi, proučavati odvojeno. Ipak, to je neizbježno u suvremenoj teorijskoj analizi. Uzmemo li u obzir visok stupanj isprepletenosti sekvencija motoričkog gibanja u izvedbi sastavnih elemenata moderne tehnike veleslalomskog zavoja, natjecateljski bismo zavoj mogli podijeliti na tri faze (Žvan i sur., 1996): a) faza ulaska u zavoj, b) faza vobenja zavoja i c) završna faza zavoja. Uzevši u obzir specifičnosti pojedinih skijaških tehnika individualnih natjecatelja, pokušali smo se u definiranju moderne veleslalomske tehnike skijanja ograničiti na dvije primarne kombinacije motoričkih struktura (Lešnik, 1999.): - tehnika koja podrazumijeva kontrolu brzine (A) - uobičajena veleslalomska tehnika koju karakterizira snažan odraz u zavoju, a definirana je izrazitim vertikalnim gibanjem; - tehnika koja podrazumijeva povećanje brzine (B) - osnovna joj je karakteristika zadržavanje niskog skijaškog položaja i smanjeno vertikalno gibanje težišta tijela, što pretpostavlja raznoliko opterećivanje i rasterećivanje skija, a naziva se lateralno gibanje. Šest skijaških eksperata usporedilo je dvije tehnike na temelju video analiza, a odbačeni su neuspjeli pokušaji. Eksperti su procjenjivali tehničke osobitosti pojedine tehnike, kao i rezultate primjene svake od njih. Osnovni cilj modernih natjecateljskih skijaških tehnika jest zadržati brzinu u svim fazama izvedbe zavoja ili, drugim riječima, ostvariti što manji gubitak brzine. To se može ostvariti tzv. lateralnim rasterećenjem gdje se u završ- noj fazi zavoja (3. faza) koljena i skije, u što je moguće kraćem vremenu, podvlače pod tijelo i guraju u suprotnu stranu u sljedeći zavoj (1. faza zavoja). Na taj se način postiže minimalno vertikalno gibanje težišta, a pritisak na snježnu podlogu je smanjen. Cilj je ovog istraživanja bio usporediti položaj trajektorija težišta tijela za vrijeme izvedbe zavoja veleslalomskim skijaškim tehnikama A i B. Metoda Mjerenje je provedeno na homologiziranoj stazi gradijenta od 15 do 20 stupnjeva, što omogućava izvođenje skijaških zavoja objema tehnikama. Također je bilo dovoljno pristupnog prostora za postizanje potrebne ulazne brzine (od oko 60 km/h) u stazu. One vožnje u kojima nije postignuta potrebna ulazna brzina za izvedbu zavoja, nisu bile analizirane, a isto tako nisu analizirane ni izvedbe zavoja koje nisu bile u skladu sa zahtjevima dviju definiranih skijaških tehnika (A ili B). Na temelju preciznog pregleda video snimaka i nakon izbacivanja nezadovoljavajućih izvedaba, odabran je uzorak vožnji. Sedam valjanih parova vožnji (tehnikom A i tehnikom B) koje je odvozilo sedam skijaša (u dobi između dvadeset i dvadeset pet godina), članova elitnog slovenskog natjecateljskog tima alpskih skijaša, korišteno je u daljnjoj analizi. Sljedeća faza bila je kompjutersko prikupljanje podataka i transformacija video snimaka u digitalni format. Za digitalizaciju je uporabljen desetosegmentni model ljudskoga tijela, a korišteno je 14 točaka. Tim smo postupkom pratili trajektorije težišta tijela (CM), koje su se, razumljivo, razlikovale ovisno o različitim antropometrijskim karakteristikama skijaša. Rezultati Statistička analiza kinematičkih parametara učinjena je pomoću SPSS statističkog paketa. Izračunati su parametri deskriptivne statistike, a zatim su razlike između dvije skijaške tehnike izračunate pomoću Studentovog t-testa za male zavisne uzorke. Kako bismo postigli bolji uvid u analizirane zavoje, analizirali smo i izračunate vrijednosti u odnosu na vremenske sekvencije varijabli. Razlike po osi x statistički su značajne u dijelu u kojem se produžava faza vođenja zavoja (faza b) u tehnici B te u dijelu završne faze zavoja (faza c) u tehnici A. Završna analiza pokazala je znatnu prednost voženja B tehnikom (88 cm). Usporedbom trajektorija CM dviju skijaških tehnika po osi z nisu dobivene statistički značajne razlike u otklonima od padne linije (os x). Rezultati pokazuju manja odstupanja trajektorija CM u tehnici B, kao i izravnije kretanje prema sljedećim vratima. Glavni nalaz, koji smo pokušali prikazati grafički (graf 1), odnosi se na kretanja trajektorija CM u ravnini XZ u povezanoj izvedbi dva veleslalomska zavoja. Najveće razlike trajektorija vidljive su u području otprilike 10-20m od osi x i 1-6m od osi z. Te razlike između tehnika A i B odnose se uglavnom na različit smjer kretanja prema sljedećim vratima: tehnika B daje izlazno-usmjereno kretanje koje je više usmjereno prema sljedećim vratima. Te razlike u smjerovima (strelice) također su posljedica prelaska u završnu fazu zavoja (faza c) u tehnici A, zbog čega dolazi do skraćivanja faze vođenja zavoja (faza b). U tehnici B, međutim, faza vođenja zavoja (b) produžena je zbog izravnijeg kretanja u smjeru sljedećih vrata, što je popraćeno bržom promjenom u kombinaciju faza ‘c-a’. Zaključak Cilj je ovog istraživanja bio usporediti različite natjecateljske tehnike (A i B). Procjenjujemo da nam podaci, kao i dobiveni razultati omogućuju opis karakteristika obiju tehnika, a istodobno i prednosti tehnike B za koju vjerujemo da ce prevladati u budućnosti. To znaci da će, usprkos težim uvjetima, skijaši skijati u nižoj poziciji, a općenito ce rasterećivati i opterećivati svoje skije u vožnji pri prijelazu iz jednoga u drugi zavoj na lateralan način. To, naravno, nije isključivo problem usavršavanja skijaške tehnike, vec je to u većoj mjeri vezano uz bolju psihofizičku kondiciju natjecatelj.Es wurde in dieser Studie eine Analyse gemacht, sowohl von der Möglichkeit, unterschiedliche moderne Riesenslalom-Techniken durchzuführen, als auch von Unterschieden zwischen diesen Techniken. Diese Forschung wurde in vereinfachten Wettkampfbedingungen an sieben Hochleistungssportlern durchgeführt. Die Analyse von ausgewählten Läufen zeigte, dass alle Sportler die Skikenntnisse hatten, die Schwünge in beiden Riesenslalom-Techniken – die Technik, die die Geschwindigkeitskontrolle impliziert, einerseits und die Technik, die die Geschwindigkeitssteigerung impliziert, andererseits – durchführen zu können. Die Analyse von kinematischen Parametern wurde zur Analyse von Hörperschwerpunkt-Flugbahnen begrenzt. Die Unterschiede wurden mittels der Studenten t-Test für abhängige Gruppen getestet. Die statistisch bedeutende Unterschiede zwischen den beiden Skitechniken zeigten sich in den Hörperschwerpunkt-Flugbahnen von Sportlern innerhalb der gemessenen Strecke (der zweite und der dritte Bogen). Diese Tatsache, zusammen mit anderen bestätigten Unterschieden zwischen den Flugbahnen in beiden Skitechniken, trug dazu bei, sowohl es zu bestätigen, dass die Technik, die die Geschwindigkeitssteigerung impliziert, vorteilhaft ist, als auch die Realisation vom theoretischen und praktischen Hintergrund dieser Studie zu befürworten

Die Korrelation zwischen einigen variablen der Explosivkraft und der Wettkampfleistung junger alpiner Schifahrer

The aim of this paper was to find the correlation between two variables of explosive power and their connection with the competitive successfulness of boys in alpine skiing. The sample comprised 24 young boys aged 12 and 13. The explosive power was analyzed by the standing triple jump (3SM) and the standing long jump (SDM). The correlation of the two independent variables of the explosive power space was statistically significant (r = 0.80). The two variables were also statistically significantly connected with the actual competitive successfulness of the tested category (35M - r = 0.52, SDM -r = 0.47). The high value of the multiple coefficient of correlation between the two mentioned tests and the criterion variable was calculated by regression analysis (Mult R = 0.53), and proved to be statistically significant Sig F = 0.03). Taking into consideration the structure of movement in alpine skiing, the significance of using both tests for the measurement of explosive power of young alpine skiers simultaneously seems quite doubtful. It was found that, regarding similar latent dimensions in the background of both independent variables, in the future it would be sounder to use only the standing triple jump test for analyzing explosive power, which is also by its structure closer to the movement structure in alpine skiing.Das Ziel dieser Arbeit war, die Korrelation zwischen zwei Variablen der Explosivkraft sowie deren Beziehung zur Wettkampfleistung junger alpiner Schifahrer festzustellen. Die Stichprobe umfasste 24 Jungen, 12 oder 13 Jahre alt. Die Explosivkraft wurde mittels Dreisprung (38M), bzw. Weitsprung (SDM) ohne Anlauf bewertet. Die Korrelation zweier unabhängigen Variablen der Explosivkraft war statistisch bedeutend (1 = 0,80). Diese zwei Variablen waren mit der eigentlichen Wettkampfleistung in den geprüften Kategorien auch statistisch bedeutend bezogen (3SM -r = 0,52; SDM -r = 0,47). Der hohe Wert des multiplen Korrelationskoeffizienten zwischen beiden Testen und der Kriteriumsvariable wurde mittels Regressionsanalyse gerechnet (Mult R = 0,53) und stellte sich als statistisch bedeutend dar (Sig F = 0,03). Zieht man die Bewegungsstruktur des alpinen Schifahrens in Betracht, scheint der Sinn simultaner Anwendung beider Teste zur Bewertung der Explosivkraft junger alpiner Schifahrer ziemlich bedenklich. Bezüglich der ähnlichen latenten Dimensionen in der Grundlage beider unabhängigen Variablen wurde festgestellt, dass es in Zukunft besser wäre, nur den Dreisprung ohne Anlauf als den Test zur Bewertung der Explosivkraft anzuwenden, weil er auch der Struktur nach den Bewegungen im alpinen Schifahren naher liegt

Die Korrelation zwischen einigen variablen der Explosivkraft und der Wettkampfleistung junger alpiner Schifahrer

The aim of this paper was to find the correlation between two variables of explosive power and their connection with the competitive successfulness of boys in alpine skiing. The sample comprised 24 young boys aged 12 and 13. The explosive power was analyzed by the standing triple jump (3SM) and the standing long jump (SDM). The correlation of the two independent variables of the explosive power space was statistically significant (r = 0.80). The two variables were also statistically significantly connected with the actual competitive successfulness of the tested category (35M - r = 0.52, SDM -r = 0.47). The high value of the multiple coefficient of correlation between the two mentioned tests and the criterion variable was calculated by regression analysis (Mult R = 0.53), and proved to be statistically significant Sig F = 0.03). Taking into consideration the structure of movement in alpine skiing, the significance of using both tests for the measurement of explosive power of young alpine skiers simultaneously seems quite doubtful. It was found that, regarding similar latent dimensions in the background of both independent variables, in the future it would be sounder to use only the standing triple jump test for analyzing explosive power, which is also by its structure closer to the movement structure in alpine skiing.Das Ziel dieser Arbeit war, die Korrelation zwischen zwei Variablen der Explosivkraft sowie deren Beziehung zur Wettkampfleistung junger alpiner Schifahrer festzustellen. Die Stichprobe umfasste 24 Jungen, 12 oder 13 Jahre alt. Die Explosivkraft wurde mittels Dreisprung (38M), bzw. Weitsprung (SDM) ohne Anlauf bewertet. Die Korrelation zweier unabhängigen Variablen der Explosivkraft war statistisch bedeutend (1 = 0,80). Diese zwei Variablen waren mit der eigentlichen Wettkampfleistung in den geprüften Kategorien auch statistisch bedeutend bezogen (3SM -r = 0,52; SDM -r = 0,47). Der hohe Wert des multiplen Korrelationskoeffizienten zwischen beiden Testen und der Kriteriumsvariable wurde mittels Regressionsanalyse gerechnet (Mult R = 0,53) und stellte sich als statistisch bedeutend dar (Sig F = 0,03). Zieht man die Bewegungsstruktur des alpinen Schifahrens in Betracht, scheint der Sinn simultaner Anwendung beider Teste zur Bewertung der Explosivkraft junger alpiner Schifahrer ziemlich bedenklich. Bezüglich der ähnlichen latenten Dimensionen in der Grundlage beider unabhängigen Variablen wurde festgestellt, dass es in Zukunft besser wäre, nur den Dreisprung ohne Anlauf als den Test zur Bewertung der Explosivkraft anzuwenden, weil er auch der Struktur nach den Bewegungen im alpinen Schifahren naher liegt

Scaffold Hopping and Bioisosteric Replacements Based on Binding Site Alignments

Bioisosteric replacements and scaffold hopping play an important role in modern drug discovery and design, as they enable the change of either a core scaffold or substitutes in a drug structure, thereby facilitating optimization of pharmacokinetic properties and patenting, while the drug retains its activity. A new knowledge-based method was developed to obtain bioisosteric or scaffold replacements based on the extensive data existing in the Protein Data Bank. The method uses all-against-all ProBiS-based protein superimposition to identify ligand fragments that overlap in similar binding sites and could therefore be considered as bioisosteric replacements. The method was demonstrated on a specific example of drug candidate – a nanomolar butyrylcholinesterase inhibitor, on which bioisosteric replacements of the three ring fragments were performed. The new molecule containing bioisosteric replacements was evaluated virtually using AutoDock Vina; a similar score for the original and the compound with replacements was obtained, suggesting that the newly designed bioisostere compound might retain the potency of the original inhibitor. This work is licensed under a Creative Commons Attribution 4.0 International License

The Influence of COVID-19 on Particulate Matter Concentrations in a Medium-Sized Town

The pandemic caused by the coronavirus COVID-19 is having a worldwide impact that affects health, econo-my and air pollution in cities indirectly. In Slovenia, as well as in all other countries, the number of cases of in-fected people increased continually in 2020, which affect-ed the health system and caused movement restrictions, which, in turn, affected the air pollution in the country. This article presents the indirect effect produced by this pandemic on air pollution in Maribor, Slovenia. Traffic and air quality data were used to perform the evaluation, in particular PM10 and PM2.5 daily concentrations from the monitoring station in Maribor. By observing the de-tailed traffic data and particulate matter concentrations acquired in the Maribor city centre before and during the pandemic times, we show the influence of COVID-19 on particulate matter concentrations in that part of the town. The results show slightly lower particulate matter con-centrations, which could be explained by the significantly lower traffic volume values in the lockdown months