This is a great, intermediate level abdominal-focused workout that can be done by itself or you can add it in to another workout. These pilates-based exercises are designed for strength and endurance. The entire series is flexion-biased so it is appropriate for healthy spines. I have also put together an abdominal workout that keeps the spine in neutral so if you know you have an active disc issue, osteoporosis, or an issue where bending forward will you put you as risk for injury, you'll want to check out the next blog, "Abs in Neutral Spine."
This is a burner! Enjoy!