Course Description:

GSDV is a rare, autosomal recessive metabolic myopathy characterized by an absence of the enzyme myophosphorylase, which is needed to break down muscle glycogen for energy production. Glycogenosis and the inability to produce muscle energy through anaerobic glycolysis severely limit the capacity for both sustained isometric exercise and strenuous aerobic exercise. The forearm ischemic test is clinically useful for confirming the diagnosis. Persons with GSDV commonly experience muscle pain and cramps, physical discomfort, and elevated perceived exertion during vigorous exercise. A unique clinical feature of GSDV is the “second-wind phenomenon”, which is associated with a shift in metabolic energy demand. Individualized exercise training might improve the functional aerobic capacity of persons with GSDV, especially those who are sedentary. In some cases, functional training might be needed to correct body mechanics and posture due to proximal muscle weakness.