Volume 16, No. 3

Authors: Jošt, Bojan

Differences between better and worse ski jumpers regarding selected ski flying characteristics at the ski flying world championships 2010 in Planica

Razlike med najbolšimi in slabšimi skakalci v izbranih značilnosti letenja na svetovnem prvenstvu v smučarskih poletih v Planici 2010

Abstract (English)

The objective of the study was to establish the differences between the best and worst ski jumpers in terms of selected ski flying characteristics at the Ski Flying World Championships 2010 in Planica. The variables Length of flying, Time of flying, In run velocity, Outrun velocity, Take off velocity, Height of flying at 17 m, Height of flying at 110 m, Aerodynamic index at 17 m, Aerodynamic index at 120 m, as well as Speed of the wind at 20 m, 70 m, 110 m and 160 m were analysed. The ski jumpers were divided into two statistically significant different quality groups according to their jump length in all four rounds (Sig t = 0.01). The velocity of movement during the flight phase increased constantly. The average out-run velocity was about 6-10% higher than the in-run velocity. The difference between the average values of in-run velocities were statistically significant in three rounds (second, third and fourth). The worse group had a greater average in-run velocity. The same happened with the variables of take-off velocity. Only a few statistically significant differences were found in the first and in the last, fourth rounds in terms of variables of out-run velocity. The worse group of ski jumpers had higher average values of out-run velocities. At the point of 17 m and especially 110 m after the edge of the take-off platform, the better group of ski jumpers had a bigger flying height. Those differences were not statistically significant in all rounds. The biggest differences were in the first and the last competitive round. The better group of ski jumpers showed a better aerodynamic flight position at the beginning of flying and especially in the middle of flying. Statistically significant differences were found in the second, third and last, fourth rounds. The differences in wind condition between defined groups were not statistically significant in general terms. In the first part of flying, only in the first round were there significant differences at the measuring point of 20 m after the take-off bridge. In the middle of flying at 110m the wind conditions were importantly different in the second and fourth jumps.

Keywords (English)

ski jumping, biomechanics, flying characteristics, World Championships 2010

Abstract (Slovenian)

Namen raziskave je bil ugotoviti razlike v prostoru izbranih značilnosti poletov na smučeh med boljšimi in slabšimi smučarji skakalci na svetovnem prvenstvu v Planici 2010. Proučevane so bile spremenljivke Dolžina poleta, Čas poleta, Zaletna hitrost, Hitrost na odrivni mizi, Višina leta v točki 17 m, Višina leta v točki 110 m, Aerodinamični indeks v točki 17 m, Aerodinamični indeks v točki 110 m, Hitrost vetra v točki 20 m, Hitrost vetra v točki 70 m, Hitrost vetra v točki 110 m in Hitrost vetra v točki 160 m. Glede na rezultate na svetovnem prvenstvu oziroma dolžine poletov v vseh štirih serijah sta bili oblikovani dve kakovostni statistično pomembno različni skupini skakalcev (Sig t = 0,01). Hitrost gibanja smučarjev skakalcev je v fazi leta stalno naraščala. Povprečna hitrost v spodnjem prehodnem loku letalnice je bila 6 – 10 % višja kot zaletna hitrost. Razlike med povprečnimi vrednostmi zaletne hitrosti so bile statistično značilne v drugi, tretji in četrti seriji. Slabša skupina je imela v povprečju večjo zaletno hitrost. Podobno se je zgodilo tudi s spremenljivko Hitrost na odskočni mizi. Pri spremenljivkah Hitrost v spodnjem prehodnem loku so bile ugotovljene statistično značilne razlike v prvi in v zadnji, četrti seriji. Slabša skupina skakalcev je imela večjo povprečno hitrost omenjene spremenljivke. Boljša skupina skakalcev je imela višjo krivuljo leta v točki 75 m in še prav posebej v točki 110 m za robom odskočne mize. Statistično pomembne razlike v višini leta so bile v točki 17 m ugotovljene v prvi in v zadnji četrti seriji in v točki 110 m v prvi seriji. Boljša skupina skakalcev je imela bolj ugoden aerodinamični indeks letenja v točki 17 m in še posebej v srednjem delu poleta v točki 110 m. Statistično značilne razlike so bile v točki 17 m ugotovljene v drugi, tretji in četrti seriji in v točki 110 m v vseh štirih serijah. Razlike v vetrovnih pogojih med definiranimi skupinami na splošno niso bile statistično značilne. V prvem delu leta, v točki 20 m, je bila samo v prvi seriji ugotovljena statistično značilna razlika. V osrednjem delu leta, v točki 110 m, so bile vetrovne razmere statistično značilno različne v drugi in četrti seriji poletov.

Keywords (Slovenian)

smučarski skoki, biomehanika, značilnosti leta, Svetovno prvenstvo 2010

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