| dc.description.abstract | The purpose of the study was to identify, describe, and
quantify selected kinematic variables associated with
the successful performance of the ski jump. Secondly,
this study attempted to determine the statistical
contribution of specific kinematic variables at takeoff
and the beginning of the transition phase for the
distance jumped.
The subjects for this investigation were 60 highly
skilled competitors participating in 1994 World Cup K-
120 event. The top twenty eight jumpers were selected
from the first and second jump of the official training
day for the K-120 event.
Data were collected using two Panasonic video cameras,
one was set up to record the take-off phase, another
was set to record the transition phase, equipped with a
high speed shutter. Data for the distance jumped were
collected from the records for the two official
training jumps held the first day of official
competition.
The 2D Peak Performance Video Analysis System was used to extract the horizontal and vertical coordinates for
a 23 segment model. The centre of mass was calculated
by a model which included 14 body segments. The data
were smoothed using a second order Butterworth digital
filter and processed to compute measures for
determining linear displacements and velocities and
angular displacements and angular velocity values. A
computer program written by the author was used to
process the data calculated for the variables selected
specifically for analysis in this study.
A correlation analysis was conducted to determine the
existence and strength of any relationships between the
selected variables and distance jumped. Seven variables
were included in the multiple regression analyses. A
full regression model provided the relative
contribution of each predictor variable to the distance
jumped. A stepwise regression model eliminated those
variables which did not contribute significantly to the
regression.
Based on the results of the study, selected kinematic
variables associated with the distance jumped were
identified and described. The similarities and difference between the traditional style and the Vstyle
of jumping were discussed. The results suggested
that the jumpers who want to increase the distance
should generate as large as possible in-run speed,
create an optimal aerodynamic body position with
forward lean movement, take a guicker drive segment
extension to begin a forward lean rotation, at the same
time keep and increase continually the velocity in the
take-off phase, keep and increase the forward lean
movement of body and extension in order to create an
optimum aerodynamic body position during the transition
phase. | |
