Monday, October 31, 2016

Top-level football refs are better at spotting fouls because of enhanced visual perception

Top-level professional football referees have enhanced visual perception, which means that they are better at spotting foul play and issuing the correct disciplinary action than lower-level referees, according to new research published in the journal Cognitive Research.

The researchers, from Belgium and the UK, had 39 football referees from the top and lower leagues in Belgium watch staged videos of fouls being committed from the point-of-view of a referee on the football pitch. Eye-tracking technology was used to assess their visual-search behaviour - that is the location that the referees' eyes fixated on and for how long.

Professor Werner Helsen, co-lead author from the University of Leuven in Belgium, said: "Our results show that elite referees have visual-search behaviour patterns that make them better at assessing foul play situations in football compared to lower league referees. When watching open play fouls being committed, elite referees spend more time fixating on the body part involved in the foul than other areas, suggesting that they are focusing on and interpreting the most crucial information within their visual display."

Visual-search behaviour is a primary skill utilised by professional athletes that enables them to coordinate perceptual-cognitive function with motor skills. Referees also rely heavily on visual-search behaviour in order to rapidly translate what they see into a correct decision based on the rules of the game. When asked to state if they thought the open-play foul committed deserved a disciplinary sanction (no card, yellow card or red card), elite referees made the correct decision with an accuracy of 61%, compared to 45% amongst lower level referees.

Dr Jochim Spitz, co-lead author, said: "Visual-search behaviour is an in-built cognitive function that can be improved through training and development. Understanding what it is exactly that makes elite referees able to make better decisions than lower-level referees could help devise training programmes specifically aimed at improving visual-search behaviour."

The video clips used in this study were filmed with the help of competitive football players who were tasked with simulating a variety of foul play scenarios including fouls in open play and from corner kicks. The action was filmed from approximately 10 meters away to mimic the proximity of a referee to the game in a real life situation. In order to make the simulations as natural as possible, no specific instructions were given to the players related to the type of foul that should be executed. A total of 20 videos were made, 10 open-play situations and 10 corner-kick situations, out of which three showed no foul play.

In the open-play and corner-kick scenarios, there was no difference between the numbers of locations that the referees focused on when watching the videos but, importantly, the elite referees did spend more time fixating on the contact zone between the attacker and the defender than the non-elite referees. Analysing the data collected from incorrect decisions made by referees, it was concluded that the fixation time plays an important role translating perceived incidents into a correct interpretation according to the 'Laws of the Game'.

Professor Werner Helsen added: "We can speculate from our results that the level of experience in elite referees is translated into long-term memory which allows their visual-search behaviour to be driven by acquired knowledge. Sub-elite referees on the other hand have less experience and seem to apply a more random control of visual fixation".

Example videos of foul play situations watched by the referees are available here:

Tuesday, October 25, 2016

Heading a football can significantly affect a player's brain function

Heading a football can significantly affect a player's brain function and memory for 24 hours, a study has found.

Researchers said they had identified "small but significant changes in brain function" after players headed the ball 20 times.

Memory performance was reduced by between 41% and 67% in the 24 hours after routine heading practice.

One of the study's authors suggested football should be avoided ahead of important events like exams.

The University of Stirling study was published in EBioMedicine.

It is the first to detect direct changes in the brain after players were exposed to everyday head impacts, as opposed to clinical brain injuries like concussion.

Researchers fired footballs from a machine designed to simulate the pace and power of a corner kick and asked a group of football players to head a ball 20 times.

The players' brain function and memory were tested before and after the exercise...

Complete article:

Wednesday, October 5, 2016

Heavy hitters: Obesity rate soars among professional baseball players


Major League Baseball players have become overwhelmingly overweight and obese during the last quarter century, say health researchers.

David E. Conroy, Penn State professor of kinesiology, and colleagues looked at 145 years of data on professional baseball players' body mass. The researchers found that the athletes' weight held steady for over 100 years, with the majority of them weighing in at what is considered "normal," -- i.e., with a body mass index (BMI) between 18.5 and 24.9.

However, around 1991 the average player's BMI began to rise, and over the last 25 years nearly 80 percent of players fall into the overweight or obese category with a BMI above 25. Obesity in the general U.S. population began to rise in the mid-1970s, according to the Centers for Disease Control and Prevention.

"Research exists that shows how having extra weight can help with certain aspects of baseball," said Conroy, also professor of human development and family studies. "The more force a batter can put into the ball, the further it will travel."

The researchers used the publicly available Lahman Baseball Database, where players' height, weight and age are recorded for their debut year in Major League Baseball. The data were self-reported, however Conroy points to the trend of players' increasing weight as informative -- and cause for some concern.

Conroy and colleagues report their findings today (Sept. 28) in Obesity Research and Clinical Practice.

"The data are observational, and raise more questions than they answer," cautioned Conroy. "BMI can be misleading, because it doesn't take body composition into account. What kind of pounds are the players adding? Are they mostly muscle or fat?"

The rise coincides with baseball's steroid era, and steroids are known to cause weight gain in some. But the rise also lines up with advances in sports science and nutrition, which have enabled athletes to better train and fuel, helping them build muscle and endurance -- which could lead to weight gain as well.

"These trends warrant further attention because of the potential for adverse long-term health consequences in this population and those who perceive them as role models for health and human performance," the researchers wrote.

Sunday, July 10, 2016

Referees add more extra time when the big teams are losing

Football (soccer) enthusiasts suspected it, but now statistics is confirming it. After analysing all the matches of the Spanish league "La Liga" from the 2014-2015 season, two experts in sports science have found that the greater the difference on the scoreboard, the less stoppage time is added to the end of the game. When the score is tighter, however, referees tend to add more stoppage time when the team in the higher division is losing.
The stoppage time added by the referee following the obligatory 90 minutes of a football match is used to compensate for time lost due to substitutions, injuries, expulsions and other incidents that arise during the game, but it seems as though other factors also play a role according to a new study.
Researchers Carlos Lago, from the University of Vigo (Spain), and Maite Gómez, from the European University of Madrid, have confirmed that referees favour the big teams by reducing the extra time when these teams are ahead on the scoreboard. In contrast, and according to an article published in the journal 'Perceptual and motor skills', referees slightly draw out the match when the big teams are losing.
To carry out the study the authors relied on data from the 380 matches played in the Spanish league during the 2014-2015 season. They then took several variables into account -such as the difference in goals on the scoreboard, the playing level of each team, the number of red and yellow cards, player substitutions, the average number of assists and fouls committed- to see if any of them had an influence on the amount of stoppage time.
After applying a statistical method (called linear regression and widely used to identify relationships between variables), it was observed that the greater the difference on the scoreboard, the less stoppage time was given by the referee. In very tight matches, nevertheless, refs tend to add more seconds when the team in the higher division is losing, and fewer seconds when they are winning. The number of red cards and fouls also cause an increase in extra time.
"The typical complaint from less powerful teams regarding how referees treat big teams better might make sense," explains Carlos Lago, "as their decisions tend to benefit the higher‑ranked teams when the scoreboard is against them. Furthermore, the more important the difference between the clubs, the greater the advantage." As the inequality between the teams decreases, because either two big teams or two small teams are playing against each other, this statistical trend disappears.
A bias that also favours local teams
Previous studies had already demonstrated that pressure from local fans also has an influence on referees when it comes to adding on more or less time. In the Spanish league, specifically, referees add 112 more seconds when the home team is losing by one goal or winning with a minimal difference.
This bias in favour of local teams was also found at football matches of the Bundesliga (Germany), Serie A (Italy), Premier League (United Kingdom), Major League Soccer (USA and Canada) and of the Campeonato Brasileiro (Brazil) leagues.
According to Lago, "what is most troubling is that the partiality of some referees for local teams and big clubs seems to have a name and surname, meaning that refs with less experience are more affected by the noise around them; there are also referees who are more or less home-biased and show a greater or lesser tendency to benefit the big teams in specific situations."
The expert in sports science concludes with some recommendations: "improve referee training and prevent subjectivity in their decisions to the extent possible, which at present have not proven to be malicious, but simply human. Additionally, technology could also help, although referee bias can decrease if they are simply aware of the role they play in the outcome of the matches."

Saturday, July 9, 2016

Wearable neuromuscular device may help reduce ACL injuries in female soccer players

Using a wearable neuromuscular device can reduce the risk of ACL injury in female soccer athletes, according to new research presented today at the American Orthopaedic Society for Sports Medicine's (AOSSM) Annual Meeting in Colorado Springs, CO. The study showed functional improvements in athletes who used the devices in combination with a regular training program.
"Our study showed that training with a wearable neuromuscular (WNM) device improved postural control in athletes, without limiting performance," said Michael John Decker, PhD, from the University of Denver in Denver, Colorado. "Moreover, no athletes in the study experienced an ACL injury during training or over the course of the following season." 
A total of 79 elite youth and collegiate female soccer players (age 12-25) in the study trained with a WNM device that applied bi-lateral, topical pressure to the medial quadriceps and hamstring muscles. The athletes performed 7 to 9 weeks of pre-season training with the device consisting of strength and conditioning exercises and on-field team practices. 
"Research has shown female soccer players have a three times greater risk of ACL injury compared to males, yet only a small portion of soccer coaches are currently utilizing ACL injury risk reduction programs," commented Decker. "We hope these devices offer coaches a practical means to overcome participation barriers, opening the door for more organizations and teams to implement similar programs."

Thursday, June 23, 2016

Mental training for soccer tactics

It's not only controlling the ball, physical endurance, and dexterity that matter when it comes to playing soccer. Members of a soccer team also have to be at the top of their game when it comes to tactical strategy. Researchers at the Cluster of Excellence Cognitive Interaction Technology (CITEC) at Bielefeld University have developed a mental training technique that helps soccer players improve their tactical action. The "kicker" here is that the players can practice with this method without actually being on the playing field.
"In soccer, as in other team sports, all players on the team have to work together harmoniously -- especially when it comes to tactical action," says Professor Dr. Thomas Schack. The sports scientist and cognitive psychologist specializes in recording how athletes store and recall sequences of action for a game in their memories. He heads the research group "Neurocognition and Action -- Biomechanics" and works at the Cluster of Excellence CITEC. "These days, there is hardly any difference in the physical fitness among soccer players of the same performance class. For this reason, the mental conception of tactical team action can be a decisive advantage." A tactically experienced team can successfully conceal their real plans from their opponents. This can help them outwit their competitors and determine the very outcome of the game. "The problem is that for many players, tactical team action is stored incorrectly -- or not at all -- in their memory. We have developed a technique that allows athletes to (re)learn this missing knowledge," explains Schack.
The new method draws upon the athlete's mental powers of imagination, and was tested with athletes who play futsal, a version of indoor soccer where the ball is passed significantly faster than in standard soccer played on a grass field. In futsal, two teams, each with five players, score by shooting into handball goalposts.
"Our technique is based on photographs and textual explanations of typical tactical situations," says Dr. Cornelia Frank, a member of Schack's research group. These photos and textual descriptions allow the players to mentally put themselves in the situation of the game, and imagine their teamwork up to and including successfully scoring a goal. The sports scientist calls the new technique "Joint Action Imagery." Dr. Frank and student Gian-Luca Linstromberg have applied and analyzed the method for the first time in a study on participants from a Bielefeld University sports group.
The test subjects were shown a photo with a scene of a tactic being played out, such as a counterattack. They were told to put themselves in the place of a certain player in the picture. As part of this mental positioning, they received an explanation of how the tactical maneuver unfolds from player's point of view, e.g.: "You intercept the ball on the right side of the field. In front of you is a member of the opposing team, and to the left and right are two players from your team. You speed up, and then pass the ball to the teammate on your right." Next, the test person was told to vividly imagine the situation ten times in a row. This mental training was practiced for four weeks, along with regular sports training at the gym. Players were led through the mental exercise twice a week, and once a week players went through the training using a script on their own at home.
Futsal players of average experience took part in the study, and a total of 12 players went through the mental training. At both the beginning and end of the study, the researchers measured how well the test subjects mentally internalized the four tactics -- playmaking, counterattack, shifting to defense, and pressing. To evaluate this, the test subjects had to make tactical decisions for different game situations. They were shown two different situations at a time and then had to judge whether the same tactic can be used to react to both cases.
"The main finding here is that the mental training enabled the players to better distinguish between the various tactics than before," says Cornelia Frank. The progress made by the test subjects was compared with a control group of futsal players, who had not participated in the mental training. "The astonishing thing in comparison to the control group was that the players that had practiced the mental training developed functional, that is, proper mental conceptions of the tactics. With this, their mental tactical skills moved towards that of professional players."
Cornelia Frank will present the new training technique at the end of July during the sports symposium of the Deutschen Vereinigung für Sportwissenschaft (German Association of Sports Sciences, dvs). The symposium will be held together with the conference "Teaching Games for Understanding." In her conference presentation, Dr. Frank will also go into greater detail on which effects of the mental training should be subject to further research: at this point, it is still unclear whether such training helps players actually make suitable tactical decisions on the playing field. It also remains to be seen whether the training helps players better understand the tactical instructions given by their coach, or makes them better able to discuss these tactics with the coach and fellow teammates. One thing, however, is clear: "With our method, players learn the basics of soccer strategy, which every coach requires, in a short amount of time. And the players get a better understanding of which tactical approach can be called upon for different situations."