Design and development of a universal OMNI exertion faces scale

[Purpose] To design and develop a new OMNI Exertion Faces Scale (OMNI Faces) that uses universal design criteria to improve acceptability for measuring perceived exertion across age groups, physical activities, and clinical populations. [Methods] The OMNI Faces Scale was developed in collaboration with the original OMNI creator and refined through consultations with educators, speech-language pathologists, clinicians, and feedback from children and adults. Design considerations included universal accessibility, simplified instructions, and alignment with the Heart Rate Reserve method. [Design Features] The OMNI Faces Scale includes five verbal descriptors and five pictorial images to reduce inconsistencies with language, activity-specific visuals, and anchoring among prior versions. The OMNI Faces Scale is non-gendered, non-activity-specific, and has accessible fonts. Instructions were simplified to 71 words relevant for assessing perceived exertion during both aerobic and resistance activities. [Conclusions] The OMNI Faces Scale was designed to provide a versatile and inclusive tool for monitoring exertion in children and adults across a broad range of physical activity applications. Future research will validate its psychometric properties across populations and activity types and explore multilingual adaptations.