It is often thought that back pain is related to the feet, and that foot problem actually leads to back problems. While some forms of back pain can be traced to the feet, the simple fact is that most cases of back pain are directly related to the spine or to organs and tissues in the flank of the body.
The exception to this lies in cases where there is abnormal foot structure or leg length. When people walk with flat feet that are unsupported, the foot becomes somewhat unstable. This instability results in a strain that travels to the inner side of the knee, and subsequently to the hip and lower back. Over time, this low level of strain can lead to fatigue of the muscles and stabilizing structure in the back, and pain can result. Conversely, people who walk with high arches can develop back pain as they have a decreased ability to absorb shock, which occurs as the foot flattens. Since high arched people cannot do this as well, the shock created by the body walking on the ground becomes transmitted to the leg, with some of that shock reaching the lower back. Pain can result from this chronic stress.
The length of the legs can also factor into the relationship between back pain and the feet. Many people have legs that are of uneven length, where one is shorter than the other. This can be due to a variety of reasons, including simple genetics, muscle imbalance, injury, and leg surgery. Walking with a shorter leg causes significant disruption to the natural mechanics of the body, and can lead to knee, hip, and back pain.