This $100 piece of equipment can help you avoid a lifetime of back pain. For a decade, I suffered from chronic lower back pain. Then, three years ago I severely herniated a disc at L5-S1. I narrowly avoided emergency surgery, and couldn’t walk for five weeks. It was the last straw. I vowed to fix my back once and for all. I went to the ends of the earth, trying everything. The most effective thing I’ve found, by far, is the simple back extension. It strengthens the entire posterior chain, including the intricate scaffold of muscles that support the spine. Start with static holds. Then, when you’ve worked up to 2 minutes, start moving as shown below. Once you can do 3 sets of 30, start adding weight (cradle it in your arms). Do it twice a week and you’ve got a solid baseline program for preventing and recovering from back problems.