CrossFlowX™: Lower Back Relief. 25 minutes. Lower back pain holding you back? This flow will help by warming you up from the inside out, loosening the muscles around your spine, activating your core to keep everything in place, opening your hips, mobilizing, and stabilizing. Deep breaths, and get ready to RELEASE! We also already have a CFZ and CFV version of this flow available, so if you want something a touch shorter, and more bedtime appropriate, OR a touch longer, and without the cardio, please check out those two.