Article

The aim of this study was to compare the first and second peaks of the vertical
ground reaction force (VGRF) and kinematics at initial contact (IC) and final
stance (FS) during walking in one of two directions (forwardxbackward) and two
environments (on landxunderwater). Twenty-two adults (24.6+/-2.6 years) walking
forward (FW) and backward (BW) on a 7.5m walkway with a central force plate.
Underwater immersion was at the height of the Xiphoid process. Ten trials were
performed for each condition giving a total of 40 trials where the VGRF and
kinematic data were recorded. Two-way repeated measures analysis of covariance
was used with a combination of environment and direction of walking: FW on land,
FW underwater, BW on land and BW underwater (entered as between-subjects factor)
and repeated measures of VGRF peaks (first and second) or angles (at IC and FS).
Walking velocity was included as a covariate. Both VGRF peaks were reduced when
participants walked underwater compared to on land (p<.001). For BW, in both
environments, the second peak was lower than the first (p<.001; for both). During
BW at IC the ankle is more dorsiflexed and the knee is more flexed, both on land
and underwater. At FS, there was no difference between the ankle angle for FW and
BW in both environments. At IC, in FW and BW the knee and hip are more flexed
underwater. BW underwater involves a lower VGRF and more knee and hip flexion
than BW on land.
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Langue : ANGLAIS