Heart rate and blood lactate correlates of perceived exertion during small-sided soccer games.

The rating of perceived exertion (RPE) could be a practical measure of global exercise intensity in team sports. The purpose of this study was to examine the relationship between heart rate (%HR(peak)) and blood lactate ([BLa(-)]) measures of exercise intensity with each player's RPE during soccer-specific aerobic exercises. Mean individual %HR(peak), [BLa(-)] and RPE (Borg's CR 10-scale) were recorded from 20 amateur soccer players from 67 soccer-specific small-sided games training sessions over an entire competitive season. The small-sided games were performed in three 4min bouts separated with 3min recovery on various sized pitches and involved 3-, 4-, 5-, or 6-players on each side. A stepwise linear multiple regression was used to determine a predictive equation to estimate global RPE for small-sided games from [BLa(-)] and %HR(peak). Partial correlation coefficients were also calculated to assess the relationship between RPE, [BLa(-)] and %HR(peak). Stepwise multiple regression analysis revealed that 43.1% of the adjusted variance in RPE could be explained by HR alone. The addition of [BLa(-)] data to the prediction equation allowed for 57.8% of the adjusted variance in RPE to be predicted (Y=-9.49-0.152 %HR(peak)+1.82 [BLa(-)], p<0.001). These results show that the combination of [BLa(-)] and %HR(peak) measures during small-sided games is better related to RPE than either %HR(peak) or [BLa(-)] measures alone. These results provide further support the use of RPE as a measure of global exercise intensity in soccer.