In swimming on the back, the action of the thoracic member is weaker,
because the swimmer can support himself on the water without their
assistance. The muscular contractions take place principally in the
muscles of the abdominal members, and in those of the anterior part of
the neck. Though little calculated for progression, it is the easiest
of all methods, because, much of the head being immersed, little effort
is required for support. For this purpose, the swimmer must lie down
gently upon the water; the body extended; the head kept in a line with
it, so that the back and much of the upper part of the head may be
immersed; the head and breast must remain perfectly unagitated by the
action of the legs; the hand laid on the thighs (Plate XXIV. fig. 1),
and the legs employed as in front swimming, care being taken that the
knees do not rise out of the water.--(Plate XXIV. fig. 2.) The arms
may, however, be used in various ways in swimming on the back.
In the method called winging, the arms are extended till in a line with
each other; they must then be struck down to the thighs, with the palms
turned in that direction, and the thumbs inclining downward to increase
the buoyancy, (Plate XXIV. fig. 3); the palms must then be moved
edgewise, and the arms elevated as before (Plate XXIV. fig. 4); and so
on, repeating the same actions. The legs should throughout make one
stroke as the arms are struck down, and another as they are elevated.
The other mode, called finning, differs from this only in the stroke of
the arms being shorter, and made in the same time as that of the legs.
In back swimming, the body should be extended after each stroke, and
long pauses made between these. The act of passing from front to back,
or back to front swimming, must always be performed immediately after
throwing out the feet. To turn from the breast to the back, the legs
must be raised forward, and the head thrown backward, until the body is
in a right position. To turn from the back to the breast, the legs must
be dropped, and the body thrown forward on the breast.