Background Pompe disease is an autosomal recessive metabolic disorder caused by the deficiency of the lysosomal enzyme acid α-glucosidase. This deficiency leads to glycogen accumulation in the lysosomes of muscle tissue causing progressive muscular weakness particularly of the respiratory system. Enzyme replacement therapy (ERT) has demonstrated efficacy in slowing down disease progression in infants. Despite the large number of studies describing the effects of physical training in juvenile and adult late onset Pompe disease (LOPD). There are very few reports that analyze the benefits of respiratory muscle rehabilitation or training. Methods The effectiveness of respiratory muscle training was investigated using a specific appliance with adjustable resistance (Threshold). The primary endpoint was effect on respiratory muscular strength by measurements of MIP and MEP. Eight late-onset Pompe patients (aged 13 to 58 years; 4 female, 4 male) with respiratory muscle deficiency on functional respiratory tests were studied. All patients received ERT at the dosage of 20 mg/kg/every 2 weeks and underwent training with Threshold at specified pressures for 24 months. Results A significant increase in MIP was observed during the follow-up of 24 month: 39.6 cm H2O (+ 25.0%) at month 3; 39.5 cm H2O (+ 24.9%) at month 6; 39.1 cm H2O (+ 23.7%) at month 9; 37.3 cm H2O (+ 18.2%) at month 12; and 37.3 cm H2O (+ 17.8%) at month 24. Median MEP values also showed a significant increase during the first 9 months: 29.8 cm H2O, (+ 14.3%) at month 3; 31.0 cm H2O (+ 18.6) at month 6; and 29.5 cm H2O (+ 12.9) at month 9. MEP was then shown to be decreased at months 12 and 24; median MEP was 27.2 cm H2O (+ 4.3%) at 12 months and 26.6 cm H2O (+ 1.9%) at 24 months. The FVC remain stable throughout the study. Conclusion An increase in respiratory muscular strength was demonstrated with Threshold training when used in combination with ERT.
