Abstract

To investigate within-player effect, between-player effect and individual response of external training load from player tracking devices on session rating of perceived exertion training load (sRPE-TL) in elite football players. Methods. We collected sRPE-TL from 18 outfield players in 21 training sessions. Total distance, high-speed running distance (HSRD; >14.4 km/h), very high-speed running distance (VHSRD; >19.8 km/h), PlayerLoadTM, PlayerLoad2DTM and high-intensity events (HIE>1.5, HIE>2.5 and HIE>3.5 m/s) were extracted from the tracking devices. We modelled within-player and between-player effects of single external load variables on sRPE-TL, and multiple levels of variability, using a linear mixed model. The effect of two standard deviations of external load on sRPE-TL were evaluated with magnitude-based inferences. Results. Total distance, PlayerLoadTM, PlayerLoad2DTM and HIE>1.5 had most likely substantial within-player effects on sRPE-TL (100-106%, very large effect sizes, ES). Moreover, we observed likely substantial between-player effects (12-19%, small to moderate ES) from the majority of the external load variables and likely to very likely substantial individual responses of PlayerLoadTM, HSRD, VHSRD and HIE>1.5 (19-30 CV%, moderate to large ES). Lastly, sRPE-TL showed large to very large between-session variability with all external load variables. Conclusions. External load variables with low intensity-thresholds had the strongest relationship with sRPE-TL. Furthermore, the between-player effect of external load, and the individual response to external load advocate for monitoring sRPE-TL in addition to external load. Finally, the large between-session variability in sRPE-TL demonstrates that substantial amounts of sRPE-TL in training sessions is not explained by single external load variables.