To investigate the effect of deep lung insufflations on maximum insufflation capacities (MICs) and peak cough flows (PCFs) for patients with neuromuscular disease.Forty-three patients with neuromuscular disease were trained in stacking delivered volumes of air to deep lung insufflation and were prescribed a program of air stacking once their vital capacities (VCs) were noted to be < 2,000 mL. VC, MIC, and unassisted and assisted PCF were monitored. The initial data were compared with the highest MICs subsequently achieved. For those patients whose MICs only decreased, we compared the initial data with the most recent data.The MICs increased from (mean +/- SD) 1,402 +/- 530 mL to 1,711 +/- 599 mL (p < 0.001) for 30 patients and only decreased for 13 patients. Patients for whom the MICs increased also had a significant increase in assisted PCF from 3.7 +/- 1.4 to 4.3 +/- 1.6 L/s (p < 0.05) despite having somewhat decreasing VCs and unassisted PCFs.With training, the capacity to stack air to deep insufflations can improve despite progressive neuromuscular disease. This can result in increased cough effectiveness.