A biomechanical study of equilibrium in sport rock climbing

Gait and Posture 10 (1999) 233 – 239
A biomechanical study of equilibrium in sport rock climbing
F. Quaine a,*, L. Martin b
www.elsevier.com/locate/gaitpost

Authors Comments:
This work shows that when a hold is removed, the
body balance requires a specifically organized arrange-
ment of supporting forces. After the hold has been
voluntarily released, the horizontal forces applied to the
ipsilateral support decrease down to zero and increase
as well onto the contralateral supports in order to
restore translational and rotational equilibrium.
At the same time, the vertical forces, which correspond to the
body weight in static conditions, remain displayed on
the three remaining holds. More precisely, the unique
solution to restore rotation equilibrium around the
vertical axis consists in decreasing the antero/posterior
force applied to the right hand hold. Moreover, the
center of gravity is quasi-unmoved which induced that
the moment of the body weight around the lateral and
antero/posterior axes remains constant. Consequently,
the only solution to counteract this moment is to
increase the antero/posterior force applied to the left
hand hold. It is thus necessary to increase the antero/
posterior force applied to LF in order to restore the
translation equilibrium along the antero/posterior axis.
Around the antero/poterior axis, the climber tends to
rotate clock-wise unless he produces important opposite
reaction forces.
In order to reduce this phenomenon,
the lateral force applied to the right hand falls off to
zero and is applied to the left hand. This induces the
decrease of the clock-wise moment due to the right
hand force, and the increase of the counterclock-wise
moment due to the left hand force. The steadiness of
the vertical force applied to the right hand is probably
due to the fact that increasing the vertical force and
decreasing at the same time the horizontal forces ap-
plied to the same hold is a complex task.