Plantar fasciitis, formerly calle "a dog's heel" in the United Kingdom, sometimes known as "flip-flop disease" among US podiatrists, is a painful inflammatory condition caused by excessive wear to the plantar fascia of the foot or biomechanical faults that cause abnormal pronation of the foot. The pain usually is felt on the underside of the heel, and is often most intense with the first steps of the day. It is commonly associated with long periods of weight bearing or sudden changes in weight bearing or activity. Obesity, weight gain, jobs that require a lot of walking on hard surfaces, shoes with little or no arch support, and inactivity are also associated with the condition. This condition often results in a heel spur on the calcaneus, in which case it is the underlying condition, and not the spur itself, which produces the pain.