In this age of overweight children, letsâ show our customers how we are helping kids to get fit through gymnastics classes. The body’s “core” refers to the muscles around the abdomen, pelvis, and back. This core is in the body’s center of gravity. As a result, it plays a role in almost all activities. From sitting to standing, walking to running, the core muscles are at work stabilizing our body against the force of gravity. We have so many ready-made activities in gymnastics class. Letâs use that as a selling point for our programs, showing that gymnastics is about adopting a healthy lifestyle while having FUN!