Quantifying Training Load in Youth Sport Athletes: A Comparison of sRPE load, the Summated Heart Rate Zone Method and External Training Load Measures

The quantification of internal (i.e., the physical stress imposed on the athlete) and external (i.e., distance covered) training load is viewed as essential to determine whether an athlete is adapting to a training programme, whilst minimising the risk of injury and overreaching. Although research has established correlations between internal measures of training load (i.e., session rating of perceived exertion [s-RPE] vs. summated heart rate zone method; Borrensen & Lambert, 2008, International Journal of Sports physiologi and performance, 3, 16-30) limited research exists comparing internal and external methods in team sports. The aim of this study was to establish the accuracy of s-RPE to quantify internal and external training load in adolescent rugby and hockey. Following institutional ethics approval, 22 youth sport (rugby & hockey) athletes were monitored across 125 training sessions (64 rugby & 61 hockey). External training load was monitored using a microtechnology unit to determine total distance and PlayerLoad, whilst internal loads were monitored using heart rate (summated heart rate zones) and s-RPE. Pearson correlation coefficients and 90% confidence intervals were calculated. Fishers r to z transformation compared the correlations between rugby and hockey. For summated HR zones and s-RPE, a large correlation (r=0.58, 90% CI: 0.43-0.70) was found for rugby with a very large correlation (r=0.75 90% CI: 0.64 to 0.83) for hockey. In rugby, large correlations were found between s-RPE and PlayerLoad (r= 0.64, 90% CI: 0.50 to 0.75), and total distance (r= 0.66 90% CI: 0.52 to 0.76). In hockey, large and moderate correlations were found between s-RPE and PlayerLoad (r= 0.55 90% CI: 0.39 to 0.69) and total distance (r= 0.42, 90% CI: 0.23 to 0.58) respectively. No significant differences were found between the correlations of internal and external measures between sports. The large and moderate correlations found between measures of total distance & PlayerLoad to s-RPE appear to support the theory that the individuals internal load is influenced by the external load they are exposed to highlighting the need for future research within this area. Furthermore, the large correlations found between s-RPE and the summated heart rate zones method highlights the potential for s-RPE to be used as an efficient technique in quantifying internal training load within adolescent rugby and hockey athletes. This suggests coaches can confidently monitor the internal training load of their athletes using s-RPE methods when HR technology is not available