In the old days, no one talked about core strengthening. Football players, ballet dancers, and gymnasts went to practice and class and did what they did. We now know that much of what these highly trained athletes were doing was designed to strengthen their core musculature.
Your core muscles include your deep abdominal muscles and your deep spinal, pelvic, and hip muscles. Core muscles are trained by large, compound movements that use your body's own weight as a gravitational load. Squats, push-ups, pull-ups, and jumping jacks are all excellent core exercises.
Again, decades ago athletic coaches never talked about core exercises. They just knew these basic, fundamental exercises were critically important for their students' success.
Additional important core exercises include the plank, pelvis press-ups, and the scorpion. Dr. Delgado will be able to help you select a group of core exercises that will work for you.