Reliability of the rating of perceived exertion at ventilatory threshold in children

The purpose of this study was to examine the reliability of the rating of perceived exertion (RPE), using the Borg 6-20 scale, at ventilatory threshold (VT) in children. Thirty children (19 male, 11 female) with a mean +/- SD age of 10.4 +/- 1.1 yrs performed two graded exercise tests for the assessment of VT and VO2max. RPE was recorded throughout each exercise test. There were no significant (p > 0.05) differences between the mean VO2max (50.9 +/- 6.0 vs 51.0 +/- 5.7 ml.kg-1.min-1; r = 0.95) or the mean VO2 at VT (36.2 +/- 4.4 vs 36.7 +/- 4.5 ml.kg-1.min-1; r = 0.87) between trials. The mean RPE at VT during trial 1 (12.4 +/- 2.7) was significantly higher than during trial 2 (11.4 +/- 3.3; p < 0.05). The test-retest reliability correlation for the RPE at VT was r = 0.78. The lower RPE in the second trial may have been due to a greater comfort and familiarity with the testing procedures. The reliability analysis indicates that the RPE at VT within a given child is fairly consistent from trial to trial. However, large inter-individual variability in the RPE at VT (range = 6 to 19) was noted and was not related to variations in the onset of VT. This raises some concern over the use of a given RPE value or range of RPE values in the regulation of exercise intensity for this age group. The test-retest reliability of VT and VO2max in this age group is similar to previous reports.