A healthy voice is essential for meeting professional and communicative demands, particularly for professional voice users such as academics, who are at increased risk of voice disorders due to prolonged and intensive voice use, unfavorable acoustic conditions, and stress. Voice disorders often result from inadequate respiratory support, leading to compensatory laryngeal overuse, vocal fatigue, and deterioration in voice quality. Although traditional voice therapy emphasizes diaphragmatic breathing, it does not enhance respiratory capacity because it lacks resistance. This study aims to investigate the effects of resistance-based breathing exercises using the Expiratory Muscle Strength Trainer (EMST 150) and triflo devices on respiratory capacity, acoustic and aerodynamic voice parameters, and vocal fatigue in academics. The findings are expected to contribute to the literature and support the use of EMST as a preventive and therapeutic approach for occupational groups at risk of voice disorders.

A healthy voice should provide information about a person's age, gender, and emotional state, while also meeting their professional, social, and communicative needs. A voice disorder is generally a change in voice quality, pitch, and/or loudness that differs from what is expected for someone of the same age or gender. In the presence of a voice disorder, the voice does not represent the speaker and cannot meet their professional, social, and communicative needs. There are many risk factors that cause voice disorders. One of these is occupation.

Speaking excessively long and loudly or at a high pitch due to one's profession is defined as voice misuse and can cause voice disorders. For example, members of professions that require intensive and prolonged use of their voices (teachers, imams, academics, telephone operators, lawyers, theater actors) are more likely to experience voice disorders. Individuals who use their voices as a primary means of communication while performing their professions are defined as professional voice users.

Although professional voice users from different occupational groups may seem to fall under the same heading, they differ in various aspects such as the frequency and method of voice use. This differentiation was classified into four levels of voice by Koufman and Isaacson (1991), and academics were included in the category of professional voice users. Voice disorders are seen in 10% of the general population and 50% of professional voice users. Despite this, there is an insufficient number of studies examining the prevalence of voice disorders in academics, risk factors, and research aimed at evaluating, diagnosing, and preventing observed voice disorders.

Professional voice users have to use their voices more effectively and intensely due to their intensive voice use, and this leads to a need for a stronger and healthier voice compared to other individuals. Risk factors that cause voice disorders in teachers, such as speaking loudly for long periods, noisy and acoustically poor working environments, dry and dusty air, and stress, also apply to academics.

In professions with high voice demands, such as teaching and academia, in addition to reducing or eliminating voice-related problems, preventive intervention programs should be implemented, and the voice should be strengthened to make it resistant to long-term and intensive use. Voice enhancement and long-term use are highly related to respiration, a component of the voice production mechanism.

Respiration, in addition to ventilating the body, provides the exhaled airflow that forms the basis of all voice and speech production. Two aspects of respiration that directly affect voice production are breath support and breath control. Breath support refers to the stabilization of body structures to create adequate air pressure and airflow; breath control refers to how an individual regulates and coordinates airflow for all activities, including speech. Difficulty in establishing and/or maintaining breath support and breath control, such as difficulties in inhaling and/or exhaling air or obtaining sufficient air, can negatively affect voice production. For example, if the respiratory system cannot provide sufficient breath support for voice production, the laryngeal system may overcompensate, leading to voice fatigue, tissue changes in the vocal cords, and changes in voice quality.

Therefore, respiratory support plays an important role in the prevention and rehabilitation of voice disorders. However, changing an individual's type of respiration (clavicular, chest, diaphragmatic) and capacity is not easy or quick. Current voice therapy approaches necessarily include breathing, but they are based on teaching diaphragmatic breathing. Teaching diaphragmatic breathing allows individuals to utilize their existing respiratory capacity, but the absence of resistance does not increase respiratory capacity. This study aims to improve the respiratory capacity and voice quality of academics who require long-term voice production, while reducing vocal fatigue, using an EMST device that enables breathing exercises against resistance. To this end, breathing exercises will be performed using the Expiratory Muscle Strength Trainer (EMST 150) and triflo devices, which allow for pressure adjustment. The application of the EMST device in academics at risk of voice disorders and the results will provide data for the literature. If the study shows an increase in acoustic voice quality, aerodynamic parameters, and exhaled volume, and a decrease in vocal fatigue, the EMST device can be included in therapy for occupational groups with or at risk of voice disorders.

Inclusion Criteria:

Having taught for at least 2 academic semesters as an academic. Having taught at least 9 hours of face-to-face classes per week. Not having been diagnosed with an organic voice disorder. Not smoking. Not being in a menstrual cycle during the pre-, mid- and post-tests.

Exclusion Criteria:

Being Pregnancy, hypertension disease have a history of stroke, heart anomaly disease chronic asthma disease emphysema or obstructive pulmonary disease, have a any surgery in the skull base and neck region, have a any neurogenic or psychological diagnosis or condition.