Wearing rocker soled shoes for just a few hours a day provides relief from back ache, a new study found.
The soles which are curved and unstable helped strengthen back muscles in order to maintain balance and stability when walking and improved the spine's curvature.
This all combined to reduce lower back pain, sports physiotherapists at CEU Cardenal Herrera University in Valencia found.
Professor Pablo Salvador said: "Patients with chronic low back pain are usually advised to perform exercises to strengthen the muscles in their back, which improve stability of the spine in the lower back area, although it is always hard to make sure they comply with this type of exercises.
"What this new study shows is that the use of unstable shoes for several hours during a patient's day-to-day life, without any other specific exercises, effectively contributes to the muscular strengthening of their back and improves the degree of curvature of the spine in the lumbar area, thus helping to reduce chronic pain."
The study involved 40 patients with low-intensity chronic low back pain.
Half wore the rocker shoes with curved soles for four weeks, and the other half used their normal shoes.
Researchers evaluated the degree of activation of the back muscles that stabilise the lumbar area with electromyography, specifically, the rectus abdominis, external oblique and internal oblique of the abdomen, as well as the erector spinae.
The curvature degree of the lower spine was also measured while wearing rocker bottom shoes, compared to ones with flat soles.
These physical results were then contrasted with the degree of pain and disability expressed by the patients, using the internationally-validated Roland-Morris Disability questionnaire.
Prof Salvador and colleague Director Dr Juan Francisco Lisón said: "The results have allowed us to confirm that everyday use of rocker bottom shoes for several hours a day reduces the disability suffered by patients with chronic low back pain."
The study was published in the journal Clinical Rehabilitation.