The role of tracking systems in modern soccer

During the last 20 years, there has been a marked increase in the number of publications investigating the use of tracking systems on measuring player’s physical performance and match/training load. The background for this has been two-fold: (1) to examine the physical performance of player’s during matches, (2) and to optimize match- and training load, in order to increase fitness and freshness, and prevent overuse injuries.

Injuries in football – an overview

Injury rates are high in modern football, and is the most common reason for player unavailability in training and matches (1). Every season there are discussions regarding injuries in football, and especially when key players are out for a prolonged period. It has been shown a relationship between increased performance and lower injury rates for professional football teams in domestic league and European cup tournaments (1), which highlights the importance of player availability. In addition, lower injury rates can save clubs for unnecassary expences. This article will in short go through the current information on injuries in football. Injury rates Injury incidence in elite football is fairly consistent, with incidence reported to to range between 25 to 30 injuries/1000 hours match play, and 3 to 5 injuries/1000 hours training (2). It has been reported from the UEFA injury study on elite European football that a typical squad of 25 players could expect 50 injuries a season, resulting in 2 injuries per player on average (3). Of these, 57% of all injuries occur during matches, and 43% during training (3). During matches, it has been shown that there is an increased tendency for injuries over time in both the first and second halves (3, 4). Statistically, the greatest injury rates have been shown Continue Reading

What are the benefits of half-time re-warm up?

The benefits of warming up prior to physical activity is well-established. The purpose of warming up is to prepare the body for the upcoming activity, in order to optimize performance. From a physiological standpoint, a warm up is an important factor in “waking up” the body. Several physiological mechanisms take place, where some of the most important are increased breathing volume and rate, increased stroke volume and dilation of blood vessels, in order to transport more oxygen to meet the metabolic demand of the working muscles. All these processes are improved by increased body temperature from a gradual warm-up. The general warm-up routine in football consists of 20-30 minutes of low- to high-intensity exercises. This physical preparation elevates muscle and body temperature, an important factor for physical performance. Studies from football has shown a relationship between increased muscle temperature and enhanced sprint performance (1), which highlights the importance of warm-up for maximal efforts at the start of match. It has been shown in football that distance covered in high-intensity running (> 14.4km×h-1) is reduced during the first 15min period of the 2nd half compared to the first 15min period of the 1st half (2). This might seem odd as one could Continue Reading

Artificial turf and injury risk

Many people are of the opinion that football should be played on natural grass, and that artificial turf could potentially increase risk of injury. Quite often, and particularly in Scandinavia, is artificial turf beneficial as a pitch surface, due to lower cost of maintenance and that it can better tolerate a high usage. Hence, more and more pitches with artificial turf are being installed throughout the world. An important question in regard to artificial turf is how injury risk in football is affected, both in terms of regular playing load on artificial turf, and frequent surface shifts between artificial turf and natural grass. This article will in short discuss the current literature in regard to artificial turf and injury risk. Type of artificial turf Artifical turf has been around for several decades, and the first generations that were introduced during the 1970s showed increased risk of injuries compared to natural grass (8). Since then, more modern turfs called third-generation artifical turfs have been developed to better replicate regular natural grass. These have shown to have better cushioning capabilities, and maintain softness over time (9). Since the early 2000s, these third-generation turfs have been the most widely used type of artificial turf. Continue Reading

The gap between elite Norwegian and European football

There has been an ongoing debate in Norway the last years in regard to the fitness level of Norwegian elite players. This has largely been due to the previous poor performances from the elite Norwegian clubs in Europe and the national team. The general opinion has been that Norwegian players lack the necessary fitness level to perform at the highest European level. Thus, the question is if this general opinion has any scientific evidence? A recent study published in Norway (1) has examined the physical performance during games of an elite Norwegian team, and gives an indication of the physical performance of elite Norwegian players compared to their European counterparts. Total distances covered The study from Ingebrigtsen and Dalen et al. (1) showed that Norwegian players cover a similar total distance to what is reported from the English Premier League (2), Spanish Primera (3) and in several elite European games (4). In regards to distance of high-speed running (> 19.8km×h-1), Norwegian players show a slightly lower distance compared to players from English Premier League (2) and elite European games (4). This indicates that players from the elite Norwegian league runs a similar distance compared to elite players from the European leagues, Continue Reading

Total distances covered during a game

Professional football players cover a total distance of 10-14km per game (1-3), including about 800m of high-intensity running (running speed > 19.8km×h-1 – 25.1km×h-1) and 300m of sprints (running speed > 25.2km×h-1)(2, 3). Positional differences There is a marked difference between each positional role and the distance they cover during a game. A study from the 2005-2006 Premier League season (2) shows that: Central defenders cover about 10km per game. They cover less distance in high-intensity running and sprints compared to all other positions. Full-backs cover about 10.7km per game. They cover more distance in high-intensity running and sprints compared to central defenders, more distance in sprints compared to central midfielders, but lower distance in high-intensity running and sprints compared to wide midfielders. Central midfielders cover about 11.5km per game. They cover a high distance in high-intensity running, but they have lower distance covered in sprints compared to full-backs and wide midfielders. Wide midfielders cover about 11.8km per game. They cover more distance in high-intensity running compared to all other positions, and sprint more than central defenders, full-backs and forwards. Forwards cover about 10.3km per game, and cover a high distance in both high-intensity running and sprints. The positional differences in total distances covered, Continue Reading