|The aim of the present study was to determine the effects of breathing
on the three - dimensional underwater stroke kinematics of front crawl
swimming. Ten female competitive freestyle swimmers participated in
the study. Each subject swam a number of front crawl trials of 25
m at a constant speed under breathing and breath-holding conditions.
The underwater motion of each subject's right arm was filmed using
two S-VHS cameras, operating at 60 Hz, which were positioned behind
two underwater viewing windows. The spatial coordinates of selected
points were calculated using the DLT procedure with 30 control points
and after the digital filtering of the raw data with a cut-off frequency
of 6 Hz, the hand's linear displacements and velocities were calculated.
The results revealed that breathing caused significantly increases
in the stroke duration (t9 = 2.764; p < 0.05), the backward hand
displacement relative to the water (t9 = 2.471; p<0.05) and the
lateral displacement of the hand in the X - axis during the downsweep
(t9 = 2.638; p < 0.05). On the contrary, the peak backward hand
velocity during the insweep (t9 = 2.368; p < 0.05) and the displacement
of the hand during the push phase (t9 = -2.297; p < 0.05) were
greatly reduced when breathing was involved. From the above, it was
concluded that breathing action in front crawl swimming caused significant
modifications in both the basic stroke parameters and the overall
motor pattern were, possibly due to body roll during breathing.
WORDS: Swimming, front crawl, three-dimensional kinematic analysis.