Monitoring Training in Elite Soccer Players: Systematic Bias Between Running Speed and Metabolic Power Data

Gaudino P., Iaia F.M., Alberti G., Strudwick A.J., Atkinson G., Gregson W.

We compared measurements of high-intensity activity during field-based training sessions in elite soccer players of different playing positions. Agreement was appraised between measurements of running speed alone and predicted metabolic power derived from a combination of running speed and acceleration. Data was collected during a 10-week phase of the competitive season from 26 English Premier League outfield players using global positioning system technology. High-intensity activity was estimated using the total distance covered at speeds > 14.4 km·h⁻¹ (TS) and the equivalent metabolic power threshold of > 20 W·kg⁻¹ (TP), respectively. We selected 0.2 as the minimally important standardised difference between methods.

Mean training session TS was 478 ± 300 m vs. 727 ± 338 m for TP (p < 0.001). This difference was greater for central defenders (~85%) vs. wide defenders and attackers (~60%) (p < 0.05). The difference between methods also decreased as the proportion of high-intensity distance within a training session increased (R² = 0.43; p < 0.001). We conclude that the high-intensity demands of soccer training are underestimated by traditional measurements of running speed alone, especially in training sessions or playing positions associated with less high-intensity activity. Estimations of metabolic power better inform the coach as to the true demands of a training session.

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