Abstract:
The long jump is an athletic event consisting of four phases viz. approach, take off,
flight and landing. Three techniques are mainly used in long jump and they have
different air dynamics. The purpose of the study was to find out the body surface
area change with the time during the long jump flight phase and how it affects the
performance. The data were collected from six national senior male long jumpers in
Sri Lanka at the national trials in 2022. Two best performers were selected from each
three techniques. Their performances were recorded in the frontal and sagittal planes
using two cameras (50Hz). The coordinates of each athlete’s center of gravity were
analyzed for each frame from start with take-off to landing phase using the Kinovea
(version 0.9.3) software and surface area was calculated using Adobe Photoshop (version
2020). Hence, the area of particular position can be calculated using pixel ratio. The
space calibration was completed from frontal plane and sagittal planes separately. The
Frontal surfaces of jumpers were calculated. The correlations between performance and
surface area in the flight phase was analyzed using the Pearson correlation method
in SPSS (version 28.0.1.1) statistical software. According to the results, the changes
of surface area and the performances of three techniques were significantly different
(p<0.05) with a negative correlation. Therefore, surface area of athlete body in flight
phase is inversely proportional to the long jump performance for the 21 positions of
entire 50 frames of the movement pattern at the points of 0.06T, 0.11T, 0.17T, 0.26T,
0.43T, 0.51T, 0.54T, 0.57T, 0.6T, 0.66T, 0.71T, 0.74T, 0.77T, 0.8T, 0.83T, 0.85T, 0.88T,
0.91T, 0.94T, 0.97T and 0.98T (where, T is the flight time) for each technique. Therefore,
the long jumpers have to minimize surface area of the body on frontal plane to optimize
their performances.
