Leaping consists principally in the sudden straightening of the
articulations, performed by a strong and instantaneous contraction of
the extensors, by which the body is rapidly projected from the ground.
The leaping-stand consists of two moveable posts, above six feet high,
having, above the second foot from the ground, holes bored through
them, at the distance of an inch from each other; two iron pins to be
placed in the holes at any height; a cord, at least ten feet long,
passed over these pins, and kept straight by two sand-bags at its
ends; and weights upon the feet of the posts, to prevent them from
falling--(Plate X. fig. 1). The leap over the cord is made from the
side of the stand towards which the heads of the pegs are turned; so
that, if the feet touch the cord, it will easily and instantly fall.
In all kinds of leaping, it is of great importance to draw in and
retain the breath at the moment of the greatest effort, as it gives
the chest more solidity to support the rest of the members, impels the
blood into the muscular parts, and increases their strength. The hands,
also, should be shut, and the arms pendent. The extent of the leap in
height, or horizontally, is proportioned to the power employed, and the
practice acquired. As it is performed with facility only in proportion
to the strength exerted, and the elasticity and suppleness of the
articulations and muscles of the lower extremities, much exercise
is necessary to attain that degree of perfection which lessens all
obstacles, and supplies the means of clearing them without danger.
Lightness and firmness are the qualities necessary for leaping: every
thing should be done to acquire these two qualifications, for without
them leaping is neither graceful nor safe.