Biomechanics and Medicine in Swimming XI

BiomechanicsandmedicineinswimmingXi
to 22.5-m) to obtain the velocity. Stroke length was calculated from the
mean speed and stroke rate values. From the video device, three operators
analysed the key points of each arm phase with a blind technique,
i.e. without knowing the analyses of the other two operators. Each arm
stroke was broken into four phases: entry and catch of the hand in the
water, pull, push and recovery. The duration of the propulsive phases
was the sum of pull and push phases and that of the non-propulsive
phases was the sum of the entry and recovery phases. Arm coordination
was quantified using the index of coordination (IdC) defined by Chollet
et al. (2000). The IdC represents the lag time between the propulsive
phases of each arm. The mean IdC, which was calculated from three
complete strokes, was expressed as a percentage of the mean stroke duration.
When there was a lag time between the propulsive phases of each
arm, the stroke coordination was in “catch-up” (IdC0% corresponded
to the “superposition” of the propulsive phases of both arms.
After checking the change of arm coordination with speed by oneway
ANOVA with repeated measures, five models of regression were
tested: power, logarithmic, exponential, linear and quadratic. Knowing
that -30%