Despite what you may have heard, core exercises involve more than simply “activating your abdominals” and crunching. The core reaches far behind the abdominals. Pilates is a great way to strengthen the core musculature, but Pilates instruction often overlooks the activation of the pelvic floor musculature, which is crucial to developing a strong core.
In the following video, I perform a Pilates style Teaser exercise with three modifications or progressions. The following exercises are advanced, but certainly possible to perform if your core is strong and you have adequate flexibility. Please read and practice the following core stabilization blogs: Tell Me More About The Core, Pelvic Floor Muscles, and Shoulder Strength-Scapular Stability and Mobility as they provide a great starting point.
If your core is weak, sadly, everything else is weak.