Relationship between indicators of training load in soccer players.

This study examined the relationship between work load indicators used to quantify full training sessions in soccer. The participants were 28 semiprofessional male soccer players age 22.9 ± 4.2 years, height 177 ± 5 cm, body mass 73.6 ± 4.4 kg. Players' physical and physiological work load was monitored over 44 training sessions using global positioning system devices (10 Hz) and heart rate, respectively. After each training session, players' training perceived-exertion (rating of perceived exertion [RPE]) was assessed using the Borg CR-10 scale. Players' internal training load was assessed using the session-RPE and the Edwards methods. Total distance, distances covered at arbitrary selected high-intensity speed zones (≥18 and 21 km·h(-1)), bout frequency at speed >18 and 21 km·h(-1), and work:rest ratio during training drills were considered as signs of physical work load. Furthermore, player load assumed as reflection of total center-of-mass acceleration was considered as representative of players' external load. Very-large association of player load with Edwards and session-RPE methods was found. Total distance covered was large to very large associated with Player Load, Session-RPE, and Edwards methods. The findings of this study provided evidence for the safe use of session-RPE, Edwards methods, and Players Load as valid indicators of training responses in soccer.