Usability and reliability of high-contrast adapted Rating of Perceived Exertion scales for sports participants with low vision.

BACKGROUND: This study investigated the usability, affective response, and reliability of visually adapted Rating of Perceived Exertion (RPE) scales developed for sports participants with low vision, aiming to enhance accessibility in Para sports. METHODS: A two-phase design was adopted. In the first phase, 20 professionals, including coaches, educators, and ophthalmologists, evaluated three adapted RPE versions (blue & yellow, black & white, and yellow & black) using the System Usability Scale (SUS). In the second phase, eight male participants with low vision assessed both traditional and adapted RPE scales across two non-consecutive days, while reporting their affective responses through the Feeling Scale. Reliability was examined using the intraclass correlation coefficient (ICC) and the typical error of measurement (TEM). RESULTS: The adapted RPE scales demonstrated good expert-based usability, with SUS scores around 78, indicating "good" and "functional." Participants tended to report more positive affective responses when using the adapted versions than when using the traditional scale. Reliability analysis indicated high consistency in affective responses for the adapted scales (ICC = 0.90-0.94) and good reliability for the traditional version (ICC = 0.88). In addition, the adapted scales showed lower measurement error (TEM = 0.29-0.40) than the traditional scale (TEM = 0.44). CONCLUSION: Overall, these findings suggest that high-contrast adaptations of the RPE scale may improve perceived usability and affective responses among participants with low vision, while maintaining consistent reliability of these responses. These results reinforce the importance of accessible design in exercise assessment tools and support the potential use of adapted RPE scales in Para sport contexts to promote greater independence and inclusion.