Ratings of perceived exertion in braille: Validity and reliabity in production mode

Abstract

Objectives - (a) To assess the validity and reliability of producing and reproducing a given exercise intensity during cycle ergometry using a braille version of Borg's standard 6-20 rating of perceived exertion (RPE) scale, and (b) to determine whether the exercise responses of blind participants, at a given produced RPE, were similar to those reported in recognised guidelines for sighted subjects. Methods - Ten healthy registered blind volunteer participants (four women, six men; mean (SD) age 23.2 (9.0) years) performed an initial graded exercise cycle test to determine maximal heart rate (HRmax) and maximal oxygen uptake (Vo2max). Three trials of three exercise bouts at RPEs 9, 11, and 13 were then performed in random order on three separate days of the same week, with expired air and heart rate measured continuously. Each exercise bout was followed by 10 minutes of rest. The validity of the scale as a means of producing different exercise intensities was assessed using a two factor (RPE x trial) repeated measures analysis of variance. Intertrial reliability was assessed using intraclass correlation coefficients (ICC) and the bias ± 95% limits of agreement (95%LoA) procedure. Results - Participants reported no difficulty in using the braille RPE scale. When asked to produce exercise intensities equating to RPE 9, 11, and 13, they elicited mean %Vo2max values of 47%, 53%, and 63% respectively. Analysis of variance showed no significant differences in either %HRmax or %Vo2max between trials at each of the three RPEs, but there was a significant difference (p<0.001) in both %HRmax and %Vo2max between the three RPE levels. All pairwise comparisons of the three different RPEs were significantly different (p<0.016). The ICC between the second and third trial for %HRmax was significant (p <0.05) for all three RPEs. Similarly for %Vo2max, the ICC was significant for RPE 9 and 11 but not 13. The 95%LoA decreased for both %HRmax and %Vo2max with each successive trial. Conclusions - Blind participants were successful in using a braille RPE scale to differentiate exercise intensity on a cycle ergometer. In every trial at RPE 13, all participants achieved %HRmax and %Vo2max levels, which fell within the recommended range for developing cardiorespiratory fitness. Using %HRmax as a judge of intertrial reliability, the participants were able to repeat similar exercise intensities after two trials at each of the three RPEs (9, 11,13). The same was true for RPE 9 and 11, when %Vo2max was used as a judge, but further trials were required to achieve similar reliability at RPE 13. A braille RPE scale can be used by healthy blind people during cycle ergometry, with similar effect to the visual analogue scale recommended for use in healthy sighted people.