Definition: To "zip up" is to drop the chest, pull in all of your abdominal muscles, and to engage the pelvic floor. The feeling is to bring everything in toward the center line. The image comes from pretending that you are putting on a pair of very tight jeans.
Also Known As: zip up, zip it up, pull in your abdominals,
Examples: You will be most successful with your Pilates exercises if you "zip it up" first.
