The relationship between heart rate recovery and temporary fatigue of kinematic and energetic indices among soccer players

he aims of the study were to investigate: 1) fluctuations in kinematic and locomotor-based metabolic power estimates during elite-level under-21 soccer matches and 2) the relationship between temporary fatigue during matches and heart rate (HR) responses to the YO-YO intermittent recovery test 1 (YO-YO IR1). High speed running (HSR), high metabolic load (HML) distances and average metabolic power (AMP) data were collected from 13 elite soccer players during six matches using global positioning systems. Indices of heart rate recovery (HRR60s; HR60s; %HRR60s) were assessed after a submaximal (YO-YO IR1). The peak 5-min period of matches was higher than both the subsequent 5-min period and the match average for all physical variables (P < 0.001). HML distance was greater (P < 0.001) in peak, post-peak and mean 5-min periods compared to HSR. Peak intensity HML distance was related to %HRR60s (r = -0.331) but not AMP (r = -0.273) or HSR distance (r = -0.224). HML distance should be used to monitor fluctuations in intensity during soccer matches. HRR measured after a submaximal YO-YO IR1 has limited potential, in the assessment of the match specific fitness of players.