Validity of PCERT and OMNI walk/run ratings of perceived exertion

Purpose: This study was conducted to test the validity of the Pictorial Children's Effort Rating Table (PCERT) and OMNI walk/run scales. Methods: Children (26 boys age 11.2 yr ± 1.6 and 25 girls age 11.1 yr ± 1.4) performed a five-stage incremental exertion treadmill test. The undifferentiated perceived exertion from the PCERT and OMNI scales was assessed for construct validity using Pearson correlations with V̊O₂ and heart rate as criteria and concurrent validity by correlating PCERT and OMNI scores. Results: Increases in PCERT and OMNI scale scores were correlated with increases in V̇O₂ (r = 0.90 and 0.92) and heart rate (r = 0.89 and 0.92). No difference was found in slope of the PCERT and OMNI scores when regressed against heart rate or V̇O₂ and the slopes were invariant across sexes. To test concurrent validity of the PCERT and OMNI scales, subject scores at each stage were converted to a percentage of the maximal scale. No effect of sex was noted on perceived exertion (P = 0.32), and the percentage of the maximal PCERT and OMNI scales was almost identical at each stage (P = 0.73). Conclusions: Validity of both the PCERT and OMNI scales was established for submaximal exercise. PCERT and OMNI scores are not interchangeable because they have different scales, but at a given exercise intensity youth assign similar percentages of the maximal scores.