Abstract
Metabolic myopathies impair muscle energy metabolism. Exercise is challenging, as patients may suffer from rhabdomyolysis attacks. This study investigated long-term effects of an individualized strength training program. Eighteen patients (12-45 years) with fatty acid oxidation disorders and glycogen storage diseases (types III and V) participated in a supervised progressive strength exercise program over two periods: biweekly assessments for 12 weeks and monthly in the second 12 weeks. Clinical assessments (anthropometry, food intake, laboratory tests), muscle strength/endurance (isokinetic tests), balance (postural stability tests), aerobic capacity (exercise duration, anaerobic threshold rate, maximal oxygen consumption), and quality of life (calculated in eight subscales) were assessed at baseline, 12, and 24 weeks. Biweekly nutritional and medical adjustments were made based on physiological responses, including modifications in caloric intake, macronutrient composition, pre-exercise sucrose and creatine supplementation. Significant improvements in strength (p < 0.001), balance (p < 0.05), and aerobic capacity (p < 0.001) were observed after 12 weeks and persisted for 24 weeks. No patients experienced rhabdomyolysis. Quality of life improved, particularly in the subscales of emotional role limitations, pain, and general health (p < 0.05). These findings suggest that dynamic, multidisciplinary, and individualized exercise program, combined with medical nutrition therapy and pharmacological adjustments, is effective and safe for patients with metabolic myopathies.