From the book "Martine, petit rat de l'opéra" by Marcel Marlier & Gilbert Delahaye; or, as I knew it, "Anita no ballet". I remember propping this up on a music stand and doing the positions in my bedroom.
Shifting Side Lunge: How to Do: Stand normally with feet together, and holding the dumbbells by your side. Take the right foot wide out, and lower into a side lunge, keeping the dumbbells on either side of your left foot. Bend the left knee with mainta