Validation of a new scale to measure perceived exertion in obese adolescents: the Childhood Obesity Perceived Exertion (Cope-10) Scale

BACKGROUND: The aim of this study was to validate a measurement scale for perceived exertion, named the Childhood Obesity Perceived Exertion Scale (COPE-10), by evaluating concurrent validity, reliability and sensitivity in obese adolescents. METHODS: Thirty obese adolescents (BMI 36.2 +/- 0.8 kg. m(-2)), aged 14.2 +/- 0.3 years, performed two incremental exercise tests (maximal followed by submaximal) before and after a multidisciplinary obesity management program. To standardize workload, physiological variables [ heart rate (HR), ventilation (E) and gas exchange (O2)] and perceived exertion (RPE) were modelized (fHR, fVE, fVO2, fRPE). At a rank of 6 on the COPE-10 Scale (RPE6) and at fixed second ventilatory threshold (VT2), we determined respectively the associated power (WPRPE6, WPVT2) and HR (HRRPE6, HRVT2). RESULTS: During maximal exercise, we observed significant correlations between fRPE and each of fHR (r=0.88; r=0.91), fVE (r=0.93; r=0.94) and fVO2 (r=0.87; r=0.89) before and after management respectively, indicating the concurrent validity of the COPE-10 Scale to estimate exercise intensity in obese adolescents. During submaximal exercise, we observed intraclass correlation coefficients of 0.77 before and 0.86 after management, showing reliability. After management, WPVT2 and WPRPE6 increased significantly (+ 23W and + 21W; P<0.001), and there was a significant correlation between HRVT2 and HRRPE6 (r=0.90), illustrating the scale's sensitivity to change. CONCLUSIONS: The COPE-10 Scale is a valid tool to measure perceived exertion in obese adolescents. This inexpensive and non-invasive instrument could be widely used in rehabilitation programs for obese youths.