Systematic bias between running speed and metabolic power data in elite soccer players: influence of drill type

• Published in: International journal of sports medicine Vol. 35; no. 6; p. 489
• Main Authors: Gaudino, P, Iaia, F M, Alberti, G, Hawkins, R D, Strudwick, A J, Gregson, W
• Format: Journal Article
• Language: English
• Published: Germany 01.06.2014
• Subjects: Acceleration; Adult; Energy Metabolism; Geographic Information Systems; Humans; Physical Education and Training - methods; Physical Endurance - physiology; Running - physiology; Soccer - physiology; Time and Motion Studies; Young Adult
• ISSN: 1439-3964
• DOI: 10.1055/s-0033-1355418

The aims of the present study were to: i) evaluate the agreement between estimates of high-intensity activity during soccer small-sided games (SSGs) based on running speed alone and estimated metabolic power derived from a combination of running speed and acceleration; ii) evaluate whether any bias between the 2 approaches is dependent upon playing position or drill characteristics. 3 types of SSGs (5vs5, 7vs7 and 10vs10) were completed by 26 English Premier League outfield players. A total of 420 individual drill observations were collected over the in-season period using portable 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). We selected 0.2 as the minimally important standardised difference between methods. High-intensity demands were systematically higher (~100%, p<0.001) when expressed as TP vs. TS irrespective of playing position and SSG. The magnitude of this difference increased as the size of SSG decreased (p<0.01) with a difference of ~200% observed in the 5vs5 SSG. A greater difference between TP and TS was also evident in central defenders compared to other positions (p<0.05) particularly during the 5vs5 SSG (~350%). We conclude that the high-intensity demands of SSGs in elite soccer players are systematically underestimated by running speed alone particularly during "small" SSGs and especially for central defenders. Estimations of metabolic power provide a more valid estimation as to the true demands of SSGs.