Monitoring external and internal loads of Brazilian soccer referees during official matches

This study aimed to assess the external and internal loads of brazilian soccer referees during official matches. a total of 11 field referees (aged 36.2 ± 7.5 years) were monitored during 35 matches. the external (distance covered,mean and maximal speed) and internal load parameters (session ratings of perceived exertion [rpe] training load [tl],edwards' tl,and time spent in different heart rate [hr] zones) were assessed in 3-4 matches per referee. external load parameters were measured using a wrist global positioning system (gps) receiver. no differences in distance covered (5.219 ± 205 vs. 5.230 ± 237 m) and maximal speed (19.3 ± 1.0 vs. 19.4 ± 1.4 km•h-1) were observed between the halves of the matches (p > 0.05). however,the mean speed was higher in the first half of the matches (6.6 ± 0.4 vs. 6.4 ± 0.3 km•h-1) (p < 0.05) than in the second half. the mean hr during the matches was ~89% of hrmax. in ~95% of the matches,the referees demonstrated a hr ≥ 80% of hrmax. nonetheless,the time spent at 90-100% of hrmaxwas higher in the first half (59.9 vs. 52.3%) (p < 0.05). significant correlations between session rpe tl and distance covered at 90-100% of hrmax(r = 0.62) and session rpe tl and maximal speed (r = 0.54) (p < 0.05) were noted. furthermore,there was a positive correlation between session rpe tl and edwards' tl (r = 0.61) (p < 0.05). brazilian soccer referees demonstrated high external and internal load demands during official matches. the portable gps/hr monitors and session rpe method can provide relevant information regarding the magnitude of the physiological strain during official matches. © journal of sports science and medicine.