Effects of Respiratory Muscle Training on Tongue Muscle Function

Inclusion Criteria: Community ambulant adults between 18 to 65 years old as of testing day; able to understand French or Dutch (depending on the study's site of inclusion); BMI ≥ 18 and ≤ 30 kg/m². Exclusion Criteria: Any diagnosed neuromuscular or cardiorespiratory disease; diagnosed psychiatric or psychological disorders which could affect adherence to or comprehension of instructions; diagnosed eating disorders; previous or ongoing head and neck cancer; diagnosed OSA; presenting a high-risk of sleep-disordered breathing indicated by a NoSAS score of 8 or higher 32 or a STOP-Bang score of 3 or higher 33,34; resting heart rate (HR) \> 100 beats per minute (bpm) or \< 50 bpm; resting systolic blood pressure (SBP) \> 140 or \< 90 mmHg, diastolic blood pressure (DBP) \> 90 or \< 50 mmHg; oxygen saturation (SpO2) \< 94% at rest on room air. Individuals with abnormal lung function, i.e., forced expiratory volume in 1 second (FEV1) ≤ 80%, forced vital capacity (FVC) ≤ 80%, and FEV1/FVC ≤ 70%, will also be excluded.