The 8th World Congress on Science and Football

The Borg CR10® scale is frequently used to calculate the Session-RPE (S-RPE) that is a valid measure of internal training load in soccer. The Borg Centimax (CR100®) scale has been suggested to provide more accurate ratings compared to CR10®. The aims of this study were to examine the validity of the CR100® and to assess its interchangeability with the CR10® insoccer. The CR100® validity was assessed in elite (SerieA) Italian players (n=19, age 28±6 yrs, height 180±7 cm, weight 77±6 kg) by correlation with the Edward’s heart-rate method. Interchangeability with CR10® was assessed in junior and semi-professional players (n=78, age 19±4 yrs, height 178±6 cm, weight 71± 6 kg) by correlation between change scores in different sessions, Bland & Altman Method with limits of agreement (LOA) and comparisons of percentage responses given at verbal expressions. Individual correlations between Edward’s method and S-RPE were large to very large (r=0.58, p=0.008 to r=0.85, p<0.008). The mean difference between CR10® vs. CR100® was -0.3±0.3 AU (90%CI -0.41,-0.29) with 95% LOA 0.31 to -0.96 AU. Correlation between two scales was r=0.95 (p<0.0001). Correlations between changes scores were nearly perfect (0.91 to 0.98, <0.0001). Ratings matching the verbal anchors were 49% and 24% in CR10® vs. CR100®, respectively. The CR100® is valid to assess internal training load and interchangeable with the CR10®. The CR100® shows a wider numerical range, more fine-graded scores and association to a percentage scale. Therefore, the use of the CR100® can improve the quality of monitoring the training process in soccer.