However, further studies with more participants are needed to support this hypothesis. Although RPE responses also increased over time (Table 2), actual RPE values ranged form 11.2 (fairly light) after first round to 13.6 (somehow hard) after third round. These results indicate that subjects underestimated actual intensity of the load determined by HR and LA responses to the fight. A recent study on validity of RPE as indicators of the actual physiological load showed that 15-point scale tends to be more valid than the 9-point scale used in this study