Abstract
The aims of this study were to: (1) verify the sex effect; (2) assess upper
limb asymmetry in anthropometrics and propulsive force variables; and (3)
identify the main determinants of butterfly swim velocity based on a set of
anthropometrics, kinematics, and propulsive force variables. Twenty swimmers
(10 males: 15.40±0.30 years; 10 females: 14.43±0.23 years)
at the national level were recruited for analysis. A set of anthropometrics,
kinematics, and propulsive force variables were measured. Overall, a
significant sex effect was verified (p≤0.05). Non-significant
differences between upper-limbs were noted for males and females in all
variables, except for the dF in males (t=−2.66,
p=0.026, d=0.66). Stroke frequency presented the highest
contribution, where a one unit increase in the stroke frequency imposed an
increase of 0.375 m·s-1 (95CI: 0.105;0.645, p=0.010)
in the swim velocity. The swim velocity was predicted by the mean propulsive
force, intra-cyclic variation of the swim velocity, and stroke frequency.
Overall, swimmers exhibit non-significant differences in the variables
assessed. Swim velocity in the butterfly stroke was determined by an
interaction of propulsive force and kinematic variables in young
swimmers.
Key words
biomechanics - kinetics - performance - youth
