CrossFlowX™: Boundary Cardio Flow. 57 Minutes. Maintaining healthy boundaries can be extremely challenging for many of us. Especially if we didn't grow up with them. This cardio flow will ask you to listen to YOU, and challenge you to get clear on exactly what your boundaries are off the mat, so you can get clear on exactly what your boundaries are off the mat. At least one yoga block is recommended, two if you have tight hamstrings, and a towel or yoga strap is optional. Deep breaths and enjoy!