Effects of the type of holds and movement amplitude on postural control associated with a climbing task

The aim of the present work was to characterize the modifications of the po stural adjustments during a climbing task as a function of postural and/or movement constraints. The variations of the horizontal and vertical forces and moments were analyzed for different movement amplitudes and types of ho lds. The results show that the horizontal momentum is influenced by all exp erimental conditions before the onset of movement. By contrast, the vertica l momentum is only influenced by the amplitude of the movement, after its o nset. These results confirm the hypothesis of a dual function of the antici patory postural adjustments. The horizontal momentum is mainly involved in the control of equilibrium. The vertical momentum contributes to the moveme nt initiation. (C) 1999 Elsevier Science B.V. All rights reserved.