Final answer:
Expiratory Muscle Strength Training (EMST) is used to improve respiratory function in various patient populations, yet it may not be indicated for those with conditions such as untreated pneumothorax, recent upper GI surgeries, or high cardiovascular risk due to thoracic pressure.
Step-by-step explanation:
The question seems to pertain to medical therapies, specifically EMST (Expiratory Muscle Strength Training) and IMT (Inspiratory Muscle Training), which are used to improve respiratory muscle function. EMST is generally utilized to enhance cough and expiratory force, which is indicated for a wide range of patient populations, including those with conditions like Parkinson's disease, multiple sclerosis, and spinal cord injuries. However, EMST may not be indicated for clients who have certain contraindications such as untreated pneumothorax, recent oropharyngeal or esophageal surgery, or those who are at risk of cardiovascular events triggered by increased thoracic pressure.