Fibrodystrophy is the proposed name for a neuromuscular syndrome, found in a series of 264 patients from the United States Army. It was originally discovered as a cause for soldiers' complaints of excessive pain and fatigue in their muscles after moderate physical exertion.

Patients with this condition are characteristically lacking in athletic ability. They have great difficulty in acquiring skill in occupations requiring fine muscle coordination,— such as typewriting, playing musical instruments, and in rifle marksmanship.

Physical examinations show three body types,—"asthenic", "obese", and "musclebound". Five simple muscle tests demonstrate the common findings,—contractures of the dorsal musculature of the body, particularly of the erector spinae, the hamstrings, and the calf muscle groups. Mild deformities—such as scoliosis, pes planus, and dorsiflexion of the interphalangeal joints of the toes—are frequently found, along with moderate muscle weakness and occasional atrophy.

The syndrome is a cause of lifelong physical disability, but it does not seem to be progressive after the adolescent growth period. Individuals thus affected, on entering military service, frequently for the first time became aware of their poor muscle development, impaired coordination, and lack of physical endurance.

The etiology of fibrodystrophy is presumed to be abortive or non-paralytic attacks of acute anterior poliomyelitis during the patient's infancy or childhood. A significant number of patients in this series either had a recognized case of poliomyelitis in their youth or some illness clinically similar to the milder forms of this disease. The muscle contractures, which are the outstanding clinical and diagnostic features of the syndrome, are considered to be the residual pathological changes of interstitial muscle fibrosis and atrophy, following the untreated muscle spasm of the acute illness.

Treatment of this condition, consisting of rest and physical therapy, is successful in relieving the patients' symptoms of muscle pain and tenderness. For the permanent pathological changes in the muscles, no specific treatment is known. The soldiers in this series were reclassified for "limited service" and duty not requiring prolonged physical exertion.