Over the weekend, I threw my back out painting my parent's fence. So I went through my usual litany of stretches trying to find out what would set it right again. I tried everything: rest, massage, anti-inflammatories, heat, ice; but nothing seemed to cure it.
When you throw your back out what has really happened is that you are experiencing a muscle spasm and/or cramp. Knowing this, and combining it with what we know about other types of muscle cramps (like a charlie horse in your calf), it is logical to try to get that muscle to contract again in order to relieve the cramp. This involves either actively contracting the muscle by tightening it, or passively manipulating it with massage. I attempted the former, active contraction, and performed a bridge, a hip extension exercise. To do a bridge, you lie on your back with your knees bent and feet flat on the floor, then you proceed to raise your hips off the floor, pausing at the top, and continuing back down to where you started. I was careful to perform a pelvic tilt prior to lifting my hips off the floor (in order to engage the deep abdominal muscles), and I also made sure to activate my glutes. The pain at first was excruciating, but after a couple of reps, my back began to immediately feel better.
It is definitely not cured at this point, but I have no pain. I still have to be careful when bending over, and I periodically activate my glutes (by squeezing my butt!), but it seems under control. Therefore the prescription to throwing out your back is to immediately begin a regimen of carefully executed bridges. Go slowly, full range of motion, and remember to activate your core and glute muscles.