The experts are not clear as what shin splints are. They may be an irritation to the tendon which attaches the muscle to the bone. Or they may be a muscle irritation or the beginning of a stress fracture.
Active people have shin splints.
They are caused by excessive walking, running, or jumping on a hard surface. But other factors include poor shoes, fallen arches, insufficient warm-up, poor posture, faulty walking and running techniques, or overstraining. Sometimes the early stages of stress fractures are thought to be shin splints or vice verse. A shin splint is a generalized pain or aching discomfort up and down the whole shin. But, if the problem is not stopped, shin splints can develop into stress fractures.