With the body well extended and all conditions sustained, lift both
legs, knees straight, hold, slowly release, then completely rest.
This exercise is the best help that can be given for a hollow back. It
also brings activity into all the abdominal muscles. It will strengthen
the muscles concerned in the support of the voice. If the chest is kept
well expanded and the lungs full of breath, the exercise will have a
wonderful effect upon the diaphragm and the respiratory mechanism. It
will strengthen and deepen the breathing and make it more central and
reposeful.