Abstract
Our aim was to determine the 3-dimensional intracycle velocity variation (IVV) of
the body centre of mass during a 200-m front crawl event, and to analyse its relation
with the segmental hand kinematics and the velocity (v) changes. 10 high-level male
swimmers performed a 200-m front crawl swim at maximal intensity. 2 above- and 4 underwater
cameras were used to record one complete non-breathing cycle for each 50-m lap, and
APASystem was used for imaging processing. The coefficient of variation was calculated
to assess the IVV in the horizontal (x), vertical (y), and lateral (z) axes; hand
kinematics was also computed. IVV remained stable across the 200 m, and significant
correlations were found between vx and vmaxx (r=0.55), vminx (r=0.68), IVVx (r= − 0.45),
and IVVz (r= − 0.45) (all p≤0.01). In addition, IVVx was correlated with the backward
horizontal amplitude normalized to stroke length (r=0.54), IVVy with hand angular
velocity (r= − 0.40), and IVVz with the elbow angle range in the pull phase (r= − 0.37)
(all p<0.05). This study shows the stability of the IVV (x,y,z), the inverse relation
of the IVV (x, z) with v, the direct relation of the vmaxx and vminx with v, and the
influence of the hand kinematics in the IVV.
Key words
swimming - biomechanics - intracycle velocity variation - 3-dimensional - front crawl
