SAthletes put less strain on their anterior cruciate ligament (ACL) while making a cut on a natural grass surface while wearing a cleat.
This is the conclusion from a study by investigators at Hospital for Special Surgery (HSS) that tested the strain placed on the ACL of four different shoe-surface interactions: Astroturf/turf shoe, modern playing turf/turf shoe, modern turf/cleat, and natural grass/cleat. The study appears in the January 2010 issue of the Journal of Biomechanical Engineering.
"It appears that a similar cut made on four different surfaces, the best strain profile is in grass/cleat combinations," said Mark Drakos, M.D., formerly an orthopedic fellow in the Sports Medicine and Shoulder Service at HSS. "So, there is less force occurring at your ligament for the same cut on that particular surface using this model."
He added that the study investigated noncontact injuries. "These are injuries where an athlete plants his or her foot while making a cut and blows out his or her knee," Dr. Drakos said. "The reason that I think this is so interesting is because there are still environmental factors, which have yet to be optimized. We don't know all the science behind why ACL injuries may be more common on turf than on grass. This study starts developing some of the science behind that, so that it can be looked at more closely because, at the end of the day, I think we need to optimize some of those environmental factors."
Previous studies have suggested that increased traction at the shoe-surface interface may increase the risk of sustaining an ACL injury. While the majority of studies reveal that ACL injuries are more likely to occur on artificial turf, there are some studies that have shown that injuries occur more frequently on grass fields. So, investigators have concluded that confounding factors, such as weather and footwear, must play a role in injuries. Some investigators have constructed models to test how the shoe-surface interface impacts loading conditions at the level of the foot, but no studies have investigated how the interface directly impacts the knee.
To fill this knowledge gap, investigators at HSS used a cadaveric model to test various shoe-surface interactions; they used the lower extremities (knee, foot, and ankle) from eight cadavers. One at a time, each specimen was positioned in a box-like structure, rigged to be in a standing position. The knee was positioned at a 30 degree angle, the flexion angle where the anterior cruciate ligament is most sensitive to strain. Investigators constructed an apparatus that placed weight on the leg, to simulate the weight of a body. Underneath the foot was a turf box that housed whatever turf they wanted to test and underneath the turf box, they placed a force plate that registered how much load was being placed on the shoe-surface interface. A lazy Susan was placed underneath the force plate that allowed the force plate and turf box to rotate. In this way, researchers could simulate a cut or a person pivoting in, for example, a soccer game.
"Our model looks at how forces travel up the kinetic chain, and that is something that should be looked at more closely, meaning you can't just look at the knee injuries by looking at the knee in isolation," Dr. Drakos said.
The investigators found that the natural grass/cleat combination placed a statistically lower maximum strain on the leg than any of the remaining three groups. All other combinations placed a greater amount of strain compared to the natural/grass cleat combination. The Astroturf shoe was 80.2 percent greater, modern playing turf/turf shoe was 47.5 percent greater, and the modern playing turf/cleat was 45.1 percent greater.
"As a former football player. I was always curious about why I was more sore after playing on artificial surfaces than playing on grass, and I wanted to find out the reasons behind that using a biomechanical model," Dr. Drakos said. "There are basically 200,000 ACL injuries every year in the United States alone and this [type of playing field and type of shoe] is an environmental factor which has been shown to play a role in injury, but has yet to be optimized. I think it is a scenario that deserves attention and further research."
Astroturf can be thought of as a carpet with ½ inch fibers on a 5 millimeter foam pad. The newer, modern playing turf consists of two inched fibers with a crumb rubber infill, three pounds of infill per square foot of turf. Investigators used fresh Kentucky bluegrass sod for the natural grass samples.
Monday, January 25, 2010
Saturday, January 23, 2010
Study: Perceived Ball Size Correlates With Batting Average
Athletes often say that when they are playing well – shooting hoops, hitting baseballs, catching passes – the ball appears bigger. Likewise, they say that when they are in a slump the ball appears smaller. When Mickey Mantle hit a 565-foot home run he said, "I just saw the ball as big as a grapefruit." But Joe "Ducky" Medwick of the St. Louis Cardinals said during a slump that he was "swinging at aspirins."
Appearances may be reality, in a sense.
A new study by University of Virginia psychologists has found a correlation between batting averages of softball players and how big, or small, they perceived the ball to be. The study documents that when the players were hitting well they clearly perceived the ball to be bigger. And when they were hitting less well, they perceived the ball to be smaller.
The interactions between mind and body – perception and action – may be as interlinked as athletes believe them to be, according to Jessica K. Witt, a cognitive psychology doctoral candidate at the University of Virginia. Witt and U.Va. psychology professor Dennis R. Proffitt describe the batting average and apparent ball size correlation in a paper that appears in the December 2005 issue of the journal Psychological Science.
The full article can be accessed online at: http://www.blackwell-synergy.com/doi/full/10.1111/j.1467-9280.2005.01640.x
"It's interesting that all the optical information is the same – the ball is only one size – but that it looks differently depending on the individual performance of the athlete," Witt said. She is interested in understanding if there is a feedback loop between perception and performance. "It's clear that the way we see the world affects the way we perform in it," she said. "I'm trying to get a glimpse into the role perception plays in streaks and slumps."
Witt and her colleagues conducted their experiment at several softball fields in Charlottesville, Va., and asked players who had finished playing for the day to look at eight different-sized circles on a board and pick the one that best represented the size of the softball they had been trying to hit. They also checked the hitting percentage of the players for that day. They found that the players who were hitting well were picking the larger circles, and the players who were batting .500 or above – those hitting safely at least half the time – were picking the largest-size circle.
The finding did not surprise Witt, a world-class athlete who competed last July for the gold medal-winning U.S. Ultimate Frisbee team at the 2005 World Games in Duisburg, Germany.
"As an athlete I've always been intrigued by how an athlete's physical performance can affect her state of mind," Witt said. "This study was designed to test what ball players have long been saying about how their performance is correlated with the way they are perceiving the ball."
Witt has experienced this herself as an athlete. She notes how she feels much more confident when she's throwing a Frisbee with the wind as opposed to against it. "The player I'm throwing to seems so far away when I'm throwing against the wind, but when I'm throwing with the wind it seems to be a short toss even if it's far," she said.
Witt plans to continue her study on perceived ball size and batting averages under controlled conditions. She hopes to obtain funding or regular access to a batting cage and competitive baseball players to design experiments that would allow her to closely monitor hitting performance, perception and the mental state of players. She is also interested in documenting whether or not visualization techniques – such as repeatedly imagining hitting a ball before going up to the plate – have any effect on performance in actuality and on whether the ball will look bigger.
Witt says such studies have implication in all areas of life – job performance, relationships, abilities and disabilities. "Perspective and perception play a big role in what we do and how well we do it," she said.
Appearances may be reality, in a sense.
A new study by University of Virginia psychologists has found a correlation between batting averages of softball players and how big, or small, they perceived the ball to be. The study documents that when the players were hitting well they clearly perceived the ball to be bigger. And when they were hitting less well, they perceived the ball to be smaller.
The interactions between mind and body – perception and action – may be as interlinked as athletes believe them to be, according to Jessica K. Witt, a cognitive psychology doctoral candidate at the University of Virginia. Witt and U.Va. psychology professor Dennis R. Proffitt describe the batting average and apparent ball size correlation in a paper that appears in the December 2005 issue of the journal Psychological Science.
The full article can be accessed online at: http://www.blackwell-synergy.com/doi/full/10.1111/j.1467-9280.2005.01640.x
"It's interesting that all the optical information is the same – the ball is only one size – but that it looks differently depending on the individual performance of the athlete," Witt said. She is interested in understanding if there is a feedback loop between perception and performance. "It's clear that the way we see the world affects the way we perform in it," she said. "I'm trying to get a glimpse into the role perception plays in streaks and slumps."
Witt and her colleagues conducted their experiment at several softball fields in Charlottesville, Va., and asked players who had finished playing for the day to look at eight different-sized circles on a board and pick the one that best represented the size of the softball they had been trying to hit. They also checked the hitting percentage of the players for that day. They found that the players who were hitting well were picking the larger circles, and the players who were batting .500 or above – those hitting safely at least half the time – were picking the largest-size circle.
The finding did not surprise Witt, a world-class athlete who competed last July for the gold medal-winning U.S. Ultimate Frisbee team at the 2005 World Games in Duisburg, Germany.
"As an athlete I've always been intrigued by how an athlete's physical performance can affect her state of mind," Witt said. "This study was designed to test what ball players have long been saying about how their performance is correlated with the way they are perceiving the ball."
Witt has experienced this herself as an athlete. She notes how she feels much more confident when she's throwing a Frisbee with the wind as opposed to against it. "The player I'm throwing to seems so far away when I'm throwing against the wind, but when I'm throwing with the wind it seems to be a short toss even if it's far," she said.
Witt plans to continue her study on perceived ball size and batting averages under controlled conditions. She hopes to obtain funding or regular access to a batting cage and competitive baseball players to design experiments that would allow her to closely monitor hitting performance, perception and the mental state of players. She is also interested in documenting whether or not visualization techniques – such as repeatedly imagining hitting a ball before going up to the plate – have any effect on performance in actuality and on whether the ball will look bigger.
Witt says such studies have implication in all areas of life – job performance, relationships, abilities and disabilities. "Perspective and perception play a big role in what we do and how well we do it," she said.
Thursday, January 21, 2010
How does an outfielder know where to run for a fly ball?
While baseball fans still rank "The Catch" by Willie Mays in the 1954 World Series as one of the greatest baseball moments of all times, scientists see the feat as more of a puzzle: How does an outfielder get to the right place at the right time to catch a fly ball?
Thousands of fans (and hundreds of thousands of YouTube viewers) saw Mays turn his back on a fly ball, race to the center field fence and catch the ball over his shoulder, seemingly a precise prediction of a fly ball's path that led his team to victory. According to a recent article in the Journal of Vision ("Catching Flyballs in Virtual Reality: A Critical Test of the Outfielder Problem"), the "outfielder problem" represents the definitive question of visual-motor control. How does the brain use visual information to guide action?
To test three theories that might explain an outfielder's ability to catch a fly ball, researcher Philip Fink, PhD, from Massey University in New Zealand and Patrick Foo, PhD, from the University of North Carolina at Ashville programmed Brown University's virtual reality lab, the VENLab, to produce realistic balls and simulate catches. The team then lobbed virtual fly balls to a dozen experienced ball players.
"The three existing theories all predict the same thing: successful catches with very similar behavior," said Brown researcher William Warren, PhD. "We realized that we could pull them apart by using virtual reality to create physically impossible fly ball trajectories."
Warren said their results support the idea that the ball players do not necessarily predict a ball's landing point based on the first part of its flight, a theory described as trajectory prediction. "Rather than predicting the landing point, the fielder might continuously track the visual motion of the ball, letting it lead him to the right place at the right time," Warren said.
Because the researchers were able to use the virtual reality lab to perturb the balls' vertical motion in ways that would not happen in reality, they were able to isolate different characteristics of each theory. The subjects tended to adjust their forward-backward movements depending on the perceived elevation angle of the incoming ball, and separately move from side to side to keep the ball at a constant bearing, consistent with the theory of optical acceleration cancellation (OAC). The third theory, linear optical trajectory (LOT), predicted that the outfielder will run in a direction that makes the visual image of the ball appear to travel in a straight line, adjusting both forward-backward and side-to-side movements together.
Fink said these results focus on the visual information a ball player receives, and that future studies could bring in other variables, such as the effect of the batter's movements or sound.
"As a first step we chose to concentrate on what seemed likely to be the most important factor," Fink said. "Fielders might also use information such as the batter's swing or the sound of the bat hitting the ball to help guide their movements."
Thousands of fans (and hundreds of thousands of YouTube viewers) saw Mays turn his back on a fly ball, race to the center field fence and catch the ball over his shoulder, seemingly a precise prediction of a fly ball's path that led his team to victory. According to a recent article in the Journal of Vision ("Catching Flyballs in Virtual Reality: A Critical Test of the Outfielder Problem"), the "outfielder problem" represents the definitive question of visual-motor control. How does the brain use visual information to guide action?
To test three theories that might explain an outfielder's ability to catch a fly ball, researcher Philip Fink, PhD, from Massey University in New Zealand and Patrick Foo, PhD, from the University of North Carolina at Ashville programmed Brown University's virtual reality lab, the VENLab, to produce realistic balls and simulate catches. The team then lobbed virtual fly balls to a dozen experienced ball players.
"The three existing theories all predict the same thing: successful catches with very similar behavior," said Brown researcher William Warren, PhD. "We realized that we could pull them apart by using virtual reality to create physically impossible fly ball trajectories."
Warren said their results support the idea that the ball players do not necessarily predict a ball's landing point based on the first part of its flight, a theory described as trajectory prediction. "Rather than predicting the landing point, the fielder might continuously track the visual motion of the ball, letting it lead him to the right place at the right time," Warren said.
Because the researchers were able to use the virtual reality lab to perturb the balls' vertical motion in ways that would not happen in reality, they were able to isolate different characteristics of each theory. The subjects tended to adjust their forward-backward movements depending on the perceived elevation angle of the incoming ball, and separately move from side to side to keep the ball at a constant bearing, consistent with the theory of optical acceleration cancellation (OAC). The third theory, linear optical trajectory (LOT), predicted that the outfielder will run in a direction that makes the visual image of the ball appear to travel in a straight line, adjusting both forward-backward and side-to-side movements together.
Fink said these results focus on the visual information a ball player receives, and that future studies could bring in other variables, such as the effect of the batter's movements or sound.
"As a first step we chose to concentrate on what seemed likely to be the most important factor," Fink said. "Fielders might also use information such as the batter's swing or the sound of the bat hitting the ball to help guide their movements."
Monday, January 11, 2010
Program may prevent knee injuries
A soccer-specific exercise program that includes individual instruction of athletes appears to reduce the risk of knee injuries in young female players, according to a report in the January 11 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Soccer is a dominant cause of sports-related injuries in part because of its increasing popularity, according to background information in the article. Between 2000 and 2006, the number of female soccer players around the world increased by 19 percent, to 26 million. "The most frequent and severe type of injury among soccer players is to the legs, especially the knees. The anterior cruciate ligament (ACL) injury incidence is highest among young athletes," the authors write. "Knee injuries, and especially ACL ruptures, may have long-term consequences, including a long absence from soccer, incomplete recovery and secondary osteoarthritis of the knee."
Ashkan Kiani, M.D., of Uppsala Primary Care, Uppsala County Council, Sweden, and colleagues assessed an intervention program specifically designed to reduce the risk of soccer-related knee injuries among 1,506 13- to 19-year-old Swedish female players. The program featured strengthening exercises designed to achieve an improved motion pattern, reducing strain on the knee joint. The training sessions were integrated into the regular soccer practices and required no additional equipment. In addition, players, parents and team leaders attended a seminar to raise awareness of injury risk.
During 2007, 777 girls on 48 teams participated in the program and 729 players on 49 teams served as controls. Three knee injuries, including one non-contact injury (not involving another player), occurred among players participating in the program, compared with 13 knee injuries and 10 non-contact injuries among girls in the control group. Therefore, the program was associated with a 77 percent reduction in the incidence of knee injuries and a 90 percent reduction in the incidence of non-contact knee injuries.
"The rate of injury was not only lower among teams participating in the preventive program but the injuries that did occur were also less severe," the authors write. All three injuries in the intervention group were categorized as major, but all three players regained full activity within six months. Among the control participants, most injuries were severe, and only four of the 13 regained full activity within six months.
Coaches reported their teams' adherence to the program at two time periods, after the preseason training period and after the competitive season. Of the 48 teams participating in the intervention, 45 (94 percent) reported a high adherence of at least 75 percent. "The high compliance rate in this study suggests that the program is easy to implement and incorporate into regular soccer practice," the authors conclude.
Soccer is a dominant cause of sports-related injuries in part because of its increasing popularity, according to background information in the article. Between 2000 and 2006, the number of female soccer players around the world increased by 19 percent, to 26 million. "The most frequent and severe type of injury among soccer players is to the legs, especially the knees. The anterior cruciate ligament (ACL) injury incidence is highest among young athletes," the authors write. "Knee injuries, and especially ACL ruptures, may have long-term consequences, including a long absence from soccer, incomplete recovery and secondary osteoarthritis of the knee."
Ashkan Kiani, M.D., of Uppsala Primary Care, Uppsala County Council, Sweden, and colleagues assessed an intervention program specifically designed to reduce the risk of soccer-related knee injuries among 1,506 13- to 19-year-old Swedish female players. The program featured strengthening exercises designed to achieve an improved motion pattern, reducing strain on the knee joint. The training sessions were integrated into the regular soccer practices and required no additional equipment. In addition, players, parents and team leaders attended a seminar to raise awareness of injury risk.
During 2007, 777 girls on 48 teams participated in the program and 729 players on 49 teams served as controls. Three knee injuries, including one non-contact injury (not involving another player), occurred among players participating in the program, compared with 13 knee injuries and 10 non-contact injuries among girls in the control group. Therefore, the program was associated with a 77 percent reduction in the incidence of knee injuries and a 90 percent reduction in the incidence of non-contact knee injuries.
"The rate of injury was not only lower among teams participating in the preventive program but the injuries that did occur were also less severe," the authors write. All three injuries in the intervention group were categorized as major, but all three players regained full activity within six months. Among the control participants, most injuries were severe, and only four of the 13 regained full activity within six months.
Coaches reported their teams' adherence to the program at two time periods, after the preseason training period and after the competitive season. Of the 48 teams participating in the intervention, 45 (94 percent) reported a high adherence of at least 75 percent. "The high compliance rate in this study suggests that the program is easy to implement and incorporate into regular soccer practice," the authors conclude.
Tuesday, December 29, 2009
Soccer Fights Depression
Despite being a significant risk group, young men are amongst those least likely to seek professional help when mentally distressed or suicidal. The 'Back of the Net' programme, a pilot initiative using football (called soccer in the U.S.) and cognitive behavioural based techniques was effective in decreasing symptoms of depression in young men. Such programmes may offer a highly accessible and cost-effective alternative route to mental health promotion in this challenging target group.
These findings were reported by Siobhain McArdle from Dublin City University to the Annual Conference of the British Psychological Society's Division of Clinical Psychology, on December 11, held at the Congress Centre in London, England.
Dr McArdle and her colleagues studied 104 sedentary males aged between 18 and 40. The men were assigned to three groups: some undertook individual exercise, some took part in a group that played football and followed a cognitive behavioural based therapy (CBT) programme, and a control group that did no exercise. The football plus CBT group incorporated the "Back of the Net" intervention, which makes use of football metaphors. This involved both participation in conditioned football sessions and interactions within each session to facilitate the transfer of lessons from the sport context into everyday life (i.e., problem solving, communication, goal setting).
The participants in the three groups were evaluated before, during and after the intervention and again eight weeks later. They found that the participants who had taken part in the exercise programmes showed significantly lower symptoms of depression (a key factor associated with suicide risk in young men). Dr McArdle says: "The two physical activity based interventions were both effective in reducing symptoms of depression in young men.
However, the "Back of the Net" intervention was specifically designed to use a low-barrier vehicle for mental health promotion. This was achieved using a popular sport to take mental health promotion onto their turf. Future research should continue to explore community-based interventions with young men that combines exercise and cognitive behavioural therapy interventions.
These findings were reported by Siobhain McArdle from Dublin City University to the Annual Conference of the British Psychological Society's Division of Clinical Psychology, on December 11, held at the Congress Centre in London, England.
Dr McArdle and her colleagues studied 104 sedentary males aged between 18 and 40. The men were assigned to three groups: some undertook individual exercise, some took part in a group that played football and followed a cognitive behavioural based therapy (CBT) programme, and a control group that did no exercise. The football plus CBT group incorporated the "Back of the Net" intervention, which makes use of football metaphors. This involved both participation in conditioned football sessions and interactions within each session to facilitate the transfer of lessons from the sport context into everyday life (i.e., problem solving, communication, goal setting).
The participants in the three groups were evaluated before, during and after the intervention and again eight weeks later. They found that the participants who had taken part in the exercise programmes showed significantly lower symptoms of depression (a key factor associated with suicide risk in young men). Dr McArdle says: "The two physical activity based interventions were both effective in reducing symptoms of depression in young men.
However, the "Back of the Net" intervention was specifically designed to use a low-barrier vehicle for mental health promotion. This was achieved using a popular sport to take mental health promotion onto their turf. Future research should continue to explore community-based interventions with young men that combines exercise and cognitive behavioural therapy interventions.
Monday, December 14, 2009
Goalkeeper's Movements and Penalty Kicks
Knowing Goalkeeper’s Movements in a Penalty Increases Success Rate and Reduces Kicker’s Decision Time
A study shows that knowing the anticipatory movements of a goalkeeper before kicking the penalty reduces the decision time and increases the success rate when choosing the direction of the shot in football (soccer). The results, extracted from the second paper by researcher F. Javier Núñez Sánchez from the University Pablo Olavide (UPO), which he wrote for his thesis, have recently been published in the scientific journal Perceptual and Motor Skills.
This research, developed by the group for Analysis of Human Movement, lead by Professor Antonio Oña of the University of Granada, has analysed the elements that interact during a penalty shootouts, including the movements and the response and reaction of the goalkeeper and the speed of the decision of the kicker when deciding the direction of the shot. According to their results, by studying the position of the goalkeeper in the instant immediately before the shot may significantly increase the probabilities of selecting a successful direction for the shot and reduces, in turn, the time of this decision process.
In the first phase, the researcher studied the movements of the goalkeeper during a penalty shootout. Among the findings, published in the International Journal of Sport Psychology in 2005, he stresses that all the goalkeepers begin their final movement instants before the player kicks that ball because, otherwise, they would not manage to reach it. These signals were named "movement pre-indexes," and help us know, in the exact moment when the player takes his last step before shooting, if the goalkeeper will jump towards his right or left before hitting the ball.
Once the aspects regarding the goalkeeper have been detected, a second phase of the study analysed the ability of the football player to decide if to hit the ball towards the right or left, in this short space of time. They also observed if it was effective or not to show the movement pre-indexes to increase success. They used a sample of 20 individuals for this study. These were later divided into four sub-groups (two control groups and two experimental groups), depending on whether the players were experts or inexperienced, i.e. those who occasionally play football and for leisure. The participants underwent two tests using a life-size projection of the goalkeepers and where the players had to simulate their penalty shot.
The professionals and the inexperienced
In the results obtained in the first test they did not find significant results between the experienced players and the inexperienced ones. However, different results were obtained after the test. After the initial test, the experimental groups watched a video that clearly explained the goalkeeper's movement pre-indexes. "During the informative film we explained where to focus, noting that when the kicker takes the last step before the penalty, he should direct the shot towards the area where the goalkeeper has the most extended knee, since he will shift towards the opposite side," states Javier Núñez.
In this sense, the decision time of the expert players in the experimental group passed from 275 to 189 milliseconds. By contrast, this decrease was barely significant in the control groups that did not receive the information on the movement pre-indexes.
As regards to the glances, the researchers registered in both tests, by means of an eye tracking system, the point in which the participants eyes were fixed before deciding the direction of the shot. In order to do this, they divided the goalkeeper's body in four sections (head-shoulders, torso, waist-knee and knee-foot). By means of this data they observed that during the first test their glances were, more or less, equally distributed. After viewing the explanations over 95% of the glances of the experimental groups were concentrated on area 3. Specifically, it is in this area, that the researchers, best observe where the goalkeeper extends his knee.
Email or share this story:
A study shows that knowing the anticipatory movements of a goalkeeper before kicking the penalty reduces the decision time and increases the success rate when choosing the direction of the shot in football (soccer). The results, extracted from the second paper by researcher F. Javier Núñez Sánchez from the University Pablo Olavide (UPO), which he wrote for his thesis, have recently been published in the scientific journal Perceptual and Motor Skills.
This research, developed by the group for Analysis of Human Movement, lead by Professor Antonio Oña of the University of Granada, has analysed the elements that interact during a penalty shootouts, including the movements and the response and reaction of the goalkeeper and the speed of the decision of the kicker when deciding the direction of the shot. According to their results, by studying the position of the goalkeeper in the instant immediately before the shot may significantly increase the probabilities of selecting a successful direction for the shot and reduces, in turn, the time of this decision process.
In the first phase, the researcher studied the movements of the goalkeeper during a penalty shootout. Among the findings, published in the International Journal of Sport Psychology in 2005, he stresses that all the goalkeepers begin their final movement instants before the player kicks that ball because, otherwise, they would not manage to reach it. These signals were named "movement pre-indexes," and help us know, in the exact moment when the player takes his last step before shooting, if the goalkeeper will jump towards his right or left before hitting the ball.
Once the aspects regarding the goalkeeper have been detected, a second phase of the study analysed the ability of the football player to decide if to hit the ball towards the right or left, in this short space of time. They also observed if it was effective or not to show the movement pre-indexes to increase success. They used a sample of 20 individuals for this study. These were later divided into four sub-groups (two control groups and two experimental groups), depending on whether the players were experts or inexperienced, i.e. those who occasionally play football and for leisure. The participants underwent two tests using a life-size projection of the goalkeepers and where the players had to simulate their penalty shot.
The professionals and the inexperienced
In the results obtained in the first test they did not find significant results between the experienced players and the inexperienced ones. However, different results were obtained after the test. After the initial test, the experimental groups watched a video that clearly explained the goalkeeper's movement pre-indexes. "During the informative film we explained where to focus, noting that when the kicker takes the last step before the penalty, he should direct the shot towards the area where the goalkeeper has the most extended knee, since he will shift towards the opposite side," states Javier Núñez.
In this sense, the decision time of the expert players in the experimental group passed from 275 to 189 milliseconds. By contrast, this decrease was barely significant in the control groups that did not receive the information on the movement pre-indexes.
As regards to the glances, the researchers registered in both tests, by means of an eye tracking system, the point in which the participants eyes were fixed before deciding the direction of the shot. In order to do this, they divided the goalkeeper's body in four sections (head-shoulders, torso, waist-knee and knee-foot). By means of this data they observed that during the first test their glances were, more or less, equally distributed. After viewing the explanations over 95% of the glances of the experimental groups were concentrated on area 3. Specifically, it is in this area, that the researchers, best observe where the goalkeeper extends his knee.
Email or share this story:
Friday, December 11, 2009
Why England's soccer team keeps losing on penalties
A new study may explain why the England soccer team keeps losing in penalty shootouts – and could help the team address the problem in time for the World Cup 2010. Research by the University of Exeter shows for the first time the effect of anxiety on a footballer's eye movements while taking a penalty.
IMAGE: Dr. Mark Wilson (L) with member of University of Exeter football team testing eye movement in penalty shoot outs.
The study shows that when penalty takers are anxious they are more likely to look at and focus on the centrally positioned goalkeeper. Due to the tight coordination between gaze control and motor control, shots also tend to centralise, making them easier to save. The research is now published in the December 2009 edition of the Journal of Sport and Exercise Psychology.
The researchers attribute this change in eye movements and focus to anxiety. Author Greg Wood of the University of Exeter's School of Sport and Health Sciences said: "During a highly stressful situation, we are more likely to be distracted by any threatening stimuli and focus on them, rather than the task in hand. Therefore, in a stressful penalty shootout, a footballer's attention is likely to be directed towards the goalkeeper as opposed to the optimal scoring zones (just inside the post). This disrupts the aiming of the shot and increases the likelihood of subsequently hitting the shot towards the goalkeeper, making it easier to save."
For their study, the researchers focused on 14 members of the University of Exeter football (soccer) team. They asked the players to perform two series of penalty shots. First, they were simply asked to do their best to score. The researchers made the second series more stressful and more akin to a penalty shoot-out. The players were told that the results would be recorded and shared with the other players and there would be a £50 prize for the best penalty taker.
The players wore special glasses which enabled the researchers to record precise eye movements and analyse the focus of each footballer's gaze and the amount of time spent looking at different locations in the goal.
The results showed that when anxious, the footballers looked at the goalkeeper significantly earlier and for longer. This change in eye behaviour made players more likely to shoot towards the centre of the goal, making it easier for the keeper to save. The researchers believe that by being made aware of the impact of anxiety on eye movements, and the affect this has on the accuracy of a player's shot, coaches could address this through training.
Greg Wood continues: "Research shows that the optimum strategy for penalty takers to use is to pick a spot and shoot to it, ignoring the goalkeeper in the process. Training this strategy is likely to build on the tight coordination between eye movements and subsequent actions, making for more accurate shooting. The idea that you cannot recreate the anxiety a penalty taker feels during a shootout is no excuse for not practicing. Do you think other elite performers don't practice basic aiming shots in darts, snooker or golf for the same reasons? These skills need to be ingrained so they are robust under pressure".
Anxiety, Attentional Control, and Performance Impairment in Penalty Kicks
IMAGE: Dr. Mark Wilson (L) with member of University of Exeter football team testing eye movement in penalty shoot outs.
The study shows that when penalty takers are anxious they are more likely to look at and focus on the centrally positioned goalkeeper. Due to the tight coordination between gaze control and motor control, shots also tend to centralise, making them easier to save. The research is now published in the December 2009 edition of the Journal of Sport and Exercise Psychology.
The researchers attribute this change in eye movements and focus to anxiety. Author Greg Wood of the University of Exeter's School of Sport and Health Sciences said: "During a highly stressful situation, we are more likely to be distracted by any threatening stimuli and focus on them, rather than the task in hand. Therefore, in a stressful penalty shootout, a footballer's attention is likely to be directed towards the goalkeeper as opposed to the optimal scoring zones (just inside the post). This disrupts the aiming of the shot and increases the likelihood of subsequently hitting the shot towards the goalkeeper, making it easier to save."
For their study, the researchers focused on 14 members of the University of Exeter football (soccer) team. They asked the players to perform two series of penalty shots. First, they were simply asked to do their best to score. The researchers made the second series more stressful and more akin to a penalty shoot-out. The players were told that the results would be recorded and shared with the other players and there would be a £50 prize for the best penalty taker.
The players wore special glasses which enabled the researchers to record precise eye movements and analyse the focus of each footballer's gaze and the amount of time spent looking at different locations in the goal.
The results showed that when anxious, the footballers looked at the goalkeeper significantly earlier and for longer. This change in eye behaviour made players more likely to shoot towards the centre of the goal, making it easier for the keeper to save. The researchers believe that by being made aware of the impact of anxiety on eye movements, and the affect this has on the accuracy of a player's shot, coaches could address this through training.
Greg Wood continues: "Research shows that the optimum strategy for penalty takers to use is to pick a spot and shoot to it, ignoring the goalkeeper in the process. Training this strategy is likely to build on the tight coordination between eye movements and subsequent actions, making for more accurate shooting. The idea that you cannot recreate the anxiety a penalty taker feels during a shootout is no excuse for not practicing. Do you think other elite performers don't practice basic aiming shots in darts, snooker or golf for the same reasons? These skills need to be ingrained so they are robust under pressure".
Anxiety, Attentional Control, and Performance Impairment in Penalty Kicks
Subscribe to:
Posts (Atom)
