Table 2. Correlation coefficients between analyzed kinematic variables in the start segment. UW Time UW Distance KF Kick count Deckick Glide time Initial-vxhead First-vxhead Last-vxhead Initial-vyhead First-vyhead Last-vyhead Initial-BA First-BA Last-BA UW-vxmean 0.005 0.21 0.21 0.19 -0.19 -0.27 -0.24 0.84†  -0.55 -0.34 -0.31 0.51 -0.32 -0.26 0.56 UW Time 0.98†  -0.28 0.84†  -0.12 -0.15 -0.06 0.58 0.18 -0.48 -0.76# -0.008 -0.55 -0.70# 0.01 UW Distance -0.22 0.87†  -0.16 -0.23 -0.15 0.68# 0.35 -0.62 -0.81†  0.12 -0.60 -0.74# 0.10 KF 0.24 -0.57 -0.70# -0.09 0.39 -0.04 0.55 -0.15 -0.003 0.51 -0.28 -0.49 Kick count -0.47 -0.60 -0.22 0.86†  0.19 -0.36 -0.85†  0.12 -0.36 -0.88†  -0.16 Deckick 0.59 -0.16 -0.51 0.08 -0.11 0.31 0.21 -0.003 0.45 0.38 Glide time 0.23 -0.82†  -0.19 -0.12 0.57 -0.25 0.04 0.69# 0.26 Initial-vxhead -0.23 -0.27 0.02 0.25 0.06 0.25 0.17 0.09 First-vxhead 0.38 -0.36 -0.81†  0.26 -0.37 -0.86†  -0.08 Last-vxhead -0.44 -0.35 0.60 -0.43 -0.33 0.32 Initial-vyhead 0.32 -0.31 0.84†  0.20 -0.45 First-vyhead -0.34 0.29 0.89†  -0.12 Last-vyhead -0.25 -0.29 0.35 Initial-BA 0.25 -0.28 First-BA 0.24 UW, underwater; vxmean, forward velocity; KF, Kick frequency, Deckick, the mean deceleration from the first to the last kick; Initial-vxhead, the forward head velocity at the feet entry; First-vxhead, the mean forward velocity during the first kick; Last-vxhead, the mean forward velocity during the last kick; Initial-vyhead, the upward head velocity at the feet entry; First-vyhead, the mean upward velocity during the first kick; Last-vyhead, the mean upward velocity during the last kick; Initial-BA, the angle of the upper body at the feet entry; First-BA, the mean angle of the upper body during the first kick; Last-BA, the mean angle of the upper body during the last kick; #, p < 0.01; † , p < 0.001