Comparing running power and teamwork
A new study was conducted using Polar Team Pro to obtain player positional data to identify how running power is related to teamwork during a soccer match.
Player position tracking allows calculation of speed and distance - conventionally used to determine game load and performance. The average total distance covered by a single player in a top-flight soccer game is between 10 to 12 km. In addition, coaches often obtain high-speed running distance to quantify how frequently players are engaged in fast-paced actions. High-speed distance is defined as integral of speed over time when certain speed threshold is exceeded.
As opposed to total distance, high-speed distance may show considerable variation between players. For example, a study found that wide players accumulated 300 m above the threshold (25 km/h), compared to 200 m by central midfielders, and 150 m by central defenders.1
Does this mean that some players work only half as hard as the others? Most likely not. Central midfielders and defenders often repeat short bouts of actions. As they seldomly exceed high-speed threshold, they accumulate less high-speed distance than others. To also account for the work required by short bouts of activities, scientists have developed methods to combine speed and acceleration to yield power as watts. This is often called running power.
In addition to measuring a players’ physical effort, recent investigations have also focused on using positional data to measure how successful players are at working as a team.
To investigate how physical effort is related to teamwork, Polar teamed up with researchers at University of Jyväskylä, Finland, to investigate how player running power is related to teamwork parameters over the duration of a soccer match.
All data was collected with Polar Team Pro. Running power was calculated using speed and acceleration, and teamwork was measured as the average distance of each player to team centroid along the width and length of field. Power and distances to centroid were reported as average of 5 min intervals.
Study was conducted in collaboration with a Finnish premier league soccer team.
The results showed there was no systematic decrease in power as the match advanced. However, correlations between power and distances to centroid revealed - in contrast to hypothesis - that decrease in power was associated with decreases in mean distances to team centroid. This implies that when players temporarily lowered their work rate, possibly due to fatigue, that did not translate to increased distance to other team members.
“The current study contained only three matches, but it taught us important lessons”, says Jussi Peltonen, a senior researcher who supervised the study for Polar. “Although we saw that player position tracking is a plausible method to compare physical effort with teamwork, there are unknown factors such as which team is attacking and whether the ball is in or out of play. Thus, to obtain better understanding of what the data means, we will probably need to link GNSS with, for example, video footage of game”, Peltonen adds.
Gregson, W., B. Drust, G. Atkinson, and V. D. Salvo. 2010. “Match-to-Match Variability of High-Speed Activities in Premier League Soccer.” International Journal of Sports Medicine 31 (4): 237–42.