The most important manual techniques used to improve the MIC and, consequently the PCF, are air stacking (AS) and glossopharyngeal breathing (GPB). These have the advantages of low cost, patient autonomy and relative ease of learning compared to other techniques using electromechanical devices (e.g., volumetric ventilators and mechanical cough assist devices), whose main disadvantages are the high cost and complexity of use. AS involves delivering multiple breaths into a manual resuscitation bag and holding the insufflation volumes with the momentary closure of the glottis, which is repeated until the MIC is reached. GPB uses the glossopharyngeal muscles to successively introduce small amounts of air into the lungs to induce coughing and assist the weak inspiratory muscles. These techniques have been useful in treating different NMD, such as Spinal Muscular Atrophy (SMA) Type II, Duchenne Muscular Dystrophy (DMD) and Spinal Cord Injury (SCI).