Hip tendonitis occurs when the thick, rope-like cords that connect the muscles to the bones of the hip become inflamed. Hip tendonitis can result from a sudden injury; however, sometimes, this condition arises for no discernable reason. Some known causes of hip tendonitis include overuse, performing twisting motions and repetitive stress being placed on the tendon. For example, individuals who run on a regular basis may develop hip tendonitis due to the repetitive stress being placed on their tendons. Symptoms of hip tendonitis may include limited mobility or range of motion and pain in the area of the affected tendon.