Are you maybe thinking of the Nada chair?
I'm not sure. I was asked by Dr. Wong's PT if we would think of using this device, and she showed me a photo but didn't remember the name. It was a large elastic band that while the child is in sitting position on the floor with legs outstretched in front of him, the band would wrap around the back and feet to keep in a stretching position. I looked up the Nada and it kind of looks like what I remember (besides having a woman sitting in a chair :) ). But wanted to know if anyone uses this device, brand names, and any advice about them.
http://community.parentprojectmd.org/forum/topics/1187424:Topic:158.... Just see if you are looking for this equipment?