This is a fantastic piece of Pilates equipment that allows the spine a greater range of motion from hyper-extension to flexion.
Through your body's proprioception it highlights the need to keep your lumber spine supported in extension thus helping in abdominal activation and building abdominal strength. I have had a series of abdominal surgeries, with that my abdominal strength went out the window but through the use of the various pieces of the equipment and using them with the exercise system I am able to find strength and length. It is also a great piece of equipment to use with clients who have bad knees.
If you have a nemesis exercise on the mat such as Roll over perhaps contemplate coming to have a private lesson on the equipment to see how it benefits the body!
At present I am working on building up to being able to lower my legs from High Scissors on the mat without collapsing. Below is a video of the small barrel leg series.
If you have a small exercise ball why not give it a go.