I slipped off an airplane seat and herniated 4 lumbar discs a few decades ago. A pro football player who was having physical therapy at the same place where I went, compared stories about backaches and what worked. He recommended infrared as his team's orthopedic guy said that it penetrates more deeply, thus can affect muscles better. It did seem to make a difference when I switched from heat therapy to infrared. And, along with everything else I did, helped me avoid surgery.