Article

Joint angle is the relative rotation between two segments where one is a
reference and assumed to be non-moving. However, rotation of the reference
segment will influence the system's spatial orientation and joint angle. The
purpose of this investigation was to determine the contribution of leg and
calcaneal rotations to ankle rotation in a weight-bearing task. Forty-eight
individuals performed partial squats recorded using a 3D motion capture system.
Markers on the calcaneus and leg were used to model leg and calcaneal segment,
and ankle joint rotations. Multiple linear regression was used to determine the
contribution of leg and calcaneal segment rotations to ankle joint dorsiflexion.
Regression models for left (R(2)=0.97) and right (R(2)=0.97) ankle dorsiflexion
were significant. Sagittal plane leg rotation had a positive influence (left:
beta=1.411; right: beta=1.418) while sagittal plane calcaneal rotation had a
negative influence (left: beta=-0.573; right: beta=-0.650) on ankle dorsiflexion.
Sagittal plane rotations of the leg and calcaneus were positively correlated
(left: r=0.84, P<0.001; right: r=0.80, P<0.001). During a partial squat, the
calcaneus rotates forward. Simultaneous forward calcaneal rotation with ankle
dorsiflexion reduces total ankle dorsiflexion angle. Rear foot posture is
reoriented during a partial squat, allowing greater leg rotation in the sagittal
plane. Segment rotations may provide greater insight into movement mechanics that
cannot be explained via joint rotations alone.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS