Project Summary/Abstract Vocal fatigue is a communication disorder that disproportionately affects occupational voice users such as teachers, call center workers, and religious officials.1–3 Classically, fatigue is composed of two dimensions: perceived fatigue and decrements in task performance.4–6 Researchers in exercise science use a variety of task protocols to elicit perceived fatigue and task performance decrements in the muscle. Only one task protocol, however—loud oral reading—is prevalent in voice research.7 Loud oral reading tasks take 1-2 hours to administer7 and expose vocally vulnerable participants to large vocal fold vibratory doses8–10 that may place them at risk of injury. In the ideal, vocal demand tasks (1) take fewer than 30 minutes to administer, (2) minimize vocal fold vibratory dose, and (3) maximize the contractile demands placed on the intrinsic laryngeal skeletal muscles most susceptible to fatigue. The goal of the proposed study is to validate a vocal demand task (the Fluid Interval Test for Voice, or FIT-V) that cleaves as closely as possible to these ideals, with the goal of sparking future vocal fatigue research and detecting, diagnosing, and treating vocal fatigue prior to the point of disability. Three specific aims support this goal: (SA1) to compare changes in perceived vocal exertion between the FIT-V task protocol and two control task protocols, (SA2) to compare vocal fold distance dose between the three tasks, assessing whether the FIT-V is non-inferior to the current standard in occupational vibratory risk,10,11 and (SA3) to screen several potential indices of task performance decrement, including pressure, flow, and biomechanical measures. The proposed training plan overseen by the University of Delaware uses multiple modalities to enhance the applicant’s ability to investigate vocal fatigue and become an independent, productive research scientist. First, mentored in-person and virtual training in disciplines such as perceived exertion, bioenergetics, and neuromuscular physiology will continue to develop the applicant’s proficiency in fatigue theory and integrated physiological systems. Second, coursework in clinical exercise physiology instrumentation and paradigms of performance testing will augment the applicant’s interdisciplinary rigor and ability to import new techniques, methods, and perspectives to voice science. Third, mentored in-person training and coursework will support the applicant’s ability to use advanced statistical techniques to analyze time-series data and accurately describe intrasubject change in fatigability over time. Fourth, data management training will improve the applicant’s ability to disseminate research findings and protect participant confidentiality. Fifth and finally, mentored training and distance coursework will teach the applicant to create simulation models of physiological systems and fatigue. These training aims will give the applicant multiple avenues through which t...