Joseph H. Pilates invented, what I believe, the powerhouse of core exercise during WWI. Confined to a prison camp during a devastating influenza outbreak that took the lives of up to 70% of rural town populations, not one of the residents in Joseph Pilates' prison camp became a statistic due to his ingenuity of a specific core exercise program using torn up bed sheets and bed springs.
Prior to commencing one of my patients/clients into a Pilates program, I make sure each individual can find their deep core stabilizing muscles and perform proper motor control of these muscles to keep themselves safe in carrying out a Pilates program. This carries over to being able to maintain a stable spine during life's dynamic demands. Pilates can be performed on a mat, with a ball, in standing, or on a variety of professional Pilates equipment.
To define your deep core muscles, check out this series on my YouTube channel.
Extending a BP cuff line - YouTube (optional)