 Stress fractures can occur in the normal bones of healthy people doing everyday activities with no apparent injury. Most stress fractures heal with little or no treatment and no permanent disability. Some are not only disabling, but dangerous. Just what is a stress fracture? A stress fracture is a painful condition occurring in a bone placed under repetitive or cyclic stress. This results in a gradual and progressive weakening of the bone which can progress to a crack and separation of the fragments. But bone is a living tissue and is in a constant state of being broken down and rebuilt under the stresses of daily living. Heavy use of a bone causes our bodies to adapt to the change and strengthen the bone at the point of stress, increasing its ability to withstand stress. But this takes time to occur. Therefore, there is a race between these two forces, the stresses which weaken the bone and our body's healing and rebuilding nature which tends to strengthen the bone. Which of these two forces wins depends on many factors, but mainly the nature of the stress and the rate at which it is applied. When the stress is causing the breaking down, exceed the body's ability to rebuild, we see the problems. How can repetitive stress actually weaken a bone? Although bone is a living tissue, it follows all of the same rules that apply to inert materials. Metal fatigue is a good analogy. Take a stout metal wire such as a coat hanger and try to break it in one single motion. You probably can't. Now repeatedly bend the wire in one place. Obviously, the more rapid the bending, the faster the breakage. But tiny repeated bendings, nevertheless, will eventually cause a gradual weakening and softening of the metal. And if continued, will eventually result in breakage. Some materials are more resistant to this situation than others, but all will break under the right circumstances. What does it feel like to have a stress fracture? Most people have experienced muscle soreness. Muscle pain, as everyone knows, rarely results in a residual problem and is even a useful indicator of the effectiveness of training. Pain is nature's way of telling us when the demands on our bodies are exceeding, even temporarily, our capacity to rebuild or adapt. Bone pain, on the other hand, that is progressive and severe enough to cause disability, for example, a limp, is a more serious indicator. Progressive bone pain, which occurs related to activity and is partially relieved by rest, is the hallmark of stress fractures. The rapidity of onset of the pain is affected by the rate of stress applied, but is rarely sudden in onset. The most important aspect is the recurrence of pain with the resumption of activity. For some unexplained reason, the pain can occur at night also. What do we see in a person with a stress fracture? In a deep-seated area like the hip, the findings may be few. However, pain is always a symptom and tenderness is usually present. It's not unusual for a soldier to have multiple stress fractures. If the bone is superficial as the shin bone, increased warmth or fever may be present in the area. X-rays may be normal, especially in the early stages. A bone scan is a useful tool in the diagnosis of stress fractures. A stress fracture will show up on a bone scan much earlier than on an x-ray. If it does, it is an indication of the bone's rebuilding activity at the point of stress. Physical disability is another useful indicator. In a weight-bearing bone, a limp is usually present. Are stress fractures very serious? In most cases, no. In the majority, although painful, they are merely an inconvenience and that the activity that caused them must be stopped or slowed down in order for the rebuilding capacity of the bones to catch up with the forces tending to weaken it. What do you mean in most cases? Some stress fractures by their particular nature and location can cause permanent, irreversible damage to a bone or nearby joint. Stress fractures about the hip, particularly in the neck of the femur, are notorious for this. The result, if such a fracture occurs, may be an operation to pin the fragments into position before they displace or to correct the displacement and pin them after they displace. Damage to the hip joint may be such that crippling is a result. At any rate, stress fractures of the hip should be handled with great respect because there is a lot at stake. Can stress fractures be prevented? Yes, by avoiding all physical activity. Obviously, this is unreasonable and particularly so in a military training setting. Stress fractures will always be a part of the medical aspect of physical training, but there are some things that we have found to be factors in decreasing their incidence. Early recognition. If the diagnosis is made before the condition becomes full-blown, the total treatment time will be less. A stitch in time saves nine and a 10-day profile in time may save a 30-day profile later. Tailor the stress to fit the individual, not the individual to fit the stress. Short-legged people put more stress on their bones than people with longer legs every time they take a step of 30 inches. This may account for the increased incidence of stress fractures in females who are generally shorter than males. Placing shorter persons at the front of a formation will permit them to set the pace and help prevent stress fractures. Other preventive measures include using non-paved surfaces for marches or running when possible, taking appropriate rest breaks on extended marches, and rotation of road guards at least daily. Strict adherence to the gradual progression concept in physical training exercises and running. Ensure the trainee is in a well-fitted and broken-in boot. Identify the unit with an abnormally high rate of stress fractures and take corrective action. Don't overreact to stress fractures. They will occur. It would be unrealistic to expect that all stress fractures could be prevented without seriously jeopardizing the training mission. Minimize their effect on training by understanding their nature and by taking appropriate action, namely by adhering to the principles of early recognition and tailoring the stress to fit the individual. The physicians and therapists are your greatest ally in accomplishing your mission of producing the trained soldier of highest possible quality. Listen to them and heed.