Cross-cultural Adaptation, Validity, and Reliability of the Borg Rating of Perceived Exertion CR-10 Scale in Portuguese Adolescents

Introduction The present investigation carried out a cross-cultural adaptation of the category-ratio Borg Scale (Borg CR - 10 scale) into Portuguese. It assessed its content validity and reliability during adolescents' progressive aerobic capacity test in school. Methods In the first phase, a cross-cultural adaptation and content validity analysis of the Borg CR-10 scale were performed, followed by a pilot study that tested the clarity of the adapted scale (n = 20, mean age of 16.20 ± 1.40 years). Content validity was verified through experts, and reliability was assessed using heart rate (HR) and Rating of Perceived Exertion (RPE) correlation during a progressive shuttle run. In the second phase, 172 adolescents (mean age of 14.50 ± 1.94 years) performed a 20-meter shuttle run test. At each stage, participants reported their RPE, and HR was recorded. Results The adapted Portuguese Borg CR-10 scale demonstrated excellent content validity (CVC = 0.993) and stage-dependent reliability, with higher agreement between RPE and HR observed in the advanced stages of the 20-meter shuttle run test ( e.g ., ICC = 0.96 at stage 12). Kendall's tau correlation was used to assess the correlation between RPE and HR across the 20-meter shuttle run test stages. Discussion Stronger correlations between RPE and HR at higher exercise intensities suggest that the Portuguese Borg CR-10 scale is particularly reliable among adolescents with greater physical fitness and training experience. Conclusion These findings support using the Portuguese Borg CR-10 scale as a valid and reliable tool for assessing perceived exertion in adolescents, particularly those with higher cardiorespiratory fitness levels. The scale is suitable for application in school-based physical education settings, offering a practical alternative to more costly physiological monitoring methods.