Evaluation and detection of Duchenne's and Becker's muscular dystrophy carriers by manual muscle testing.

Manual muscle testing of mothers of patients with X-linked muscular dystrophy has demonstrated patterns of proximal muscle weakness. The degree of weakness usually has little effect on activities of daily living but can be detected by standardized "break" testing with manual stabilization of body parts, elimination of synergistic muscles, and mechanical advantage given to the patient. Manual muscle testing is a valuable adjunct to the clinical and biochemical tools available for detecting carriers.