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All soccer players and fans know that it is better to win than to lose. Yet the fact that victory also means less risk of injury is not as obvious. New findings from researchers in sports medicine at Linköping University have aroused great interest among Europe's elite soccer teams.
Håkan Bengtsson, a master's student in physiotherapy, has analysed data from 6272 games played by 26 of the top European clubs. The material comprises 2739 injuries and constitutes the world's largest database of its kind. The results was tabled at a regional conference on physiotherapy in Linköping March 22.
Based on information the clubs sent to the Swedish researchers once a month, Håkan Bengtsson then examined how the injury rate is influenced by three factors:
* the result
* home or away match
* type of competition
It turned out that the outcome of the match had the clearest correlation with the proportion of injuries. For teams that lost, the risk of injury was 21 percent greater than for the winning teams; in drawn games the risk was 15 percent higher.
"We have not established which is the chicken or the egg. The most likely scenario is that a player was injured during the match, which subsequently lead to a loss. The bottom line is that the clubs' medical work is vital to the results," says Håkan Bengtsson.
Bengtsson was somewhat surprised that a higher injury risk ensued for the home team than the away team. One conceivable explanation is that home teams play more aggressively coupled with longer and faster running sorties. With regard to the type of competition, Champions League matches appeared somewhat more dangerous than for the rhythm of the domestic leagues.
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Friday, March 23, 2012
Tuesday, February 7, 2012
Competitive Soccer Linked to Increased Injuries and Menstrual Dysfunction in Girls
Regular warm-up exercises can significantly decrease ACL injury risk
In the U.S., there are nearly three million youth soccer players, and half of them are female. New research presented today at the 2012 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that despite reporting appropriate body perception and attitudes toward eating, elite youth soccer athletes (club level or higher) face an increased risk for delayed or irregular menstruation. In addition, female soccer players are more likely to suffer a stress fracture or ligament injury. A separate study found that a consistent 15-minute warm-up substantially decreases knee injury risk.
The Female Triad (Menstrual Dysfunction, Eating Attitudes, Stress Fractures) in Soccer Athletes"
The “female athlete triad” – menstrual dysfunction, eating attitudes and stress fractures – puts female athletes at risk for diminished performance and long-term health problems.
To determine the prevalence of the female triad among soccer players, investigators recruited 220 athletes, median age 16.4, from an elite youth soccer club, an NCAA Division I university team, and a women’s professional team. The participating athletes completed questionnaires regarding age of menarche (first menstruation), menstrual history, and history of musculoskeletal injuries including stress fractures. The Eating Attitudes Test was used to assess each athlete’s body image, and attitudes toward eating.
The average age of menarche was 13 years of age among the participants. Irregular menstruation cycles, or absence of menstruation, were reported by 19 percent of the participants in the 15-17 age group, 18 percent of the college-age players, and 20 percent of the professional athletes. A history of stress fractures was reported in 14 percent of the players, with a majority of the injuries in the ankle and foot.
Only one player scored in the “high risk” range, and 16 in the “potentially high risk range,” in terms of body perception and eating attitudes.“Elite female soccer athletes are at risk for delayed onset of menarche, menstrual dysfunction and stress fractures, which may be due to an imbalance of energy intake and output,” said Robert H. Brophy, MD, co-investigator and assistant professor of orthopaedic surgery at Washington University School of Medicine in St. Louis, Mo. “The risk for soccer athletes appears to be lower than for female athletes in aesthetic (gymnastics, dancing, etc.) and endurance sports. More research is needed to identify the underlying causes, and potential remedies, for these findings in elite female soccer athletes, and whether these findings translate to female athletes participating in other team sports.”
A Randomized Trial of Anterior Cruciate Ligament Injury Prevention in Adolescent Female Soccer.
In another study, investigators studied the effects of a regular, progressive warm-up exercise program on knee injuries and health.
The study involved more than 4,500 female soccer players in Sweden, age 12-17, from 309 elite clubs. The players were randomly assigned to one of two groups: an intervention group instructed to complete a 15-minute muscular warm-up consisting of six progressively more difficult knee and core stability exercises, twice a week throughout the 2009 season, and a non warm-up “control” group. Team coaches documented player participating during the season, and acute knee injuries were examined by the physical therapist and/or physician assigned to each club.
There was a 64 percent decrease in anterior cruciate ligament (ACL) injuries in the intervention group, and an 83 percent reduction among “compliant,” fully participating players. In addition, there was a “significant” decrease in the rates of all severe knee injuries.
“We showed a statistically significant reduction – by almost two-thirds – in ACL injuries in (participating) female teenage soccer players in a coach-directed neuromuscular warm-up program,” said Markus Waldén, MD, PhD, lead investigator, and an orthopaedic surgeon at Hässeleholm-Kristianstad Hospitals in Hässeleholm, Sweden. “Interestingly, players (who complied) had a reduction in other acute knee injuries as well.
“The program is intended to replace the ordinary warm-up and thus does not steal time from soccer training,” said Dr. Waldén.
Tuesday, January 10, 2012
Frequent "Heading" in Soccer Can Lead to Brain Injury and Cognitive Impairment
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Using advanced imaging techniques and cognitive tests, researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center, the University Hospital and academic medical center for Einstein, have shown that repeatedly heading a soccer ball increases the risk for brain injury and cognitive impairment. The imaging portion of the findings was presented today at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.
The researchers used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 38 amateur soccer players (average age: 30.8 years) who had all played the sport since childhood. They were asked to recall the number of times they headed the ball during the past year. (Heading is when players deliberately hit or field the soccer ball with their head.) Researchers ranked the players based on heading frequency and then compared the brain images of the most frequent headers with those of the remaining players. They found that frequent headers showed brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury (TBI).
The findings are especially concerning given that soccer is the world's most popular sport with popularity growing in the U.S., especially among children. Of the 18 million Americans who play soccer, 78 percent are under the age of eighteen. Soccer balls are known to travel at speeds as high as 34 miles per hour during recreational play, and more than twice that during professional play.
After confirming the potentially damaging impact of frequent heading, "Our goal was to determine if there is a threshold level for heading frequency that, when surpassed, resulted in detectable brain injury," said lead author Michael Lipton, M.D., Ph.D., director of Einstein's Gruss Magnetic Resonance Research Center and medical director of MRI services at Montefiore. Further analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study exceeded that number, researchers observed significant injury.
"While heading a ball 1,000 or 1,500 times a year may seem high to those who don't participate in the sport, it only amounts to a few times a day for a regular player," observed Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences, and of the Dominick P. Purpura Department of Neuroscience at Einstein.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain," said Dr. Lipton. "But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells."
Researchers identified five areas, in the frontal lobe (behind the forehead) and in the temporo-occipital region (the bottom-rear areas) of the brain that were affected by frequent heading – areas that are responsible for attention, memory, executive functioning and higher-order visual functions. In a related study, Dr. Lipton and colleague Molly Zimmerman, Ph.D., assistant professor in the Saul R. Korey Department of Neurology at Einstein, gave the same 38 amateur soccer players tests designed to assess their neuropsychological function. Players with the highest annual heading frequency performed worse on tests of verbal memory and psychomotor speed (activities that require mind-body coordination, like throwing a ball) relative to their peers.
"These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency," Dr. Lipton said. "These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players."
Heading is an essential part of soccer and is unlikely to be eliminated from practice or play. As there appears to be a safe range for heading frequency, additional research can help refine this number, which can then be used to establish heading guidelines. As in other sports, the frequency of potentially harmful actions in practice and games could be monitored and restricted based on confirmed unsafe exposure thresholds.
"In the past, pitchers in Little League Baseball sustained shoulder injuries at a rate that was alarming," Dr. Lipton noted. "But ongoing research has helped shape various approaches, including limits on the amount of pitching a child performs, which have substantially reduced the incidence of these injuries."
"Brain injury due to heading in children, if we confirm that it occurs, may not show up on our radar because the impairment will not be immediate and can easily be attributed to other causes like ADHD or learning disabilities," continued Dr. Lipton. "We, including the agencies that supervise and encourage soccer play, need to do the further research to precisely define the impact of excessive heading on children and adults in order to develop parameters within which soccer play will be safe over the long term."
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Using advanced imaging techniques and cognitive tests, researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center, the University Hospital and academic medical center for Einstein, have shown that repeatedly heading a soccer ball increases the risk for brain injury and cognitive impairment. The imaging portion of the findings was presented today at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.
The researchers used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 38 amateur soccer players (average age: 30.8 years) who had all played the sport since childhood. They were asked to recall the number of times they headed the ball during the past year. (Heading is when players deliberately hit or field the soccer ball with their head.) Researchers ranked the players based on heading frequency and then compared the brain images of the most frequent headers with those of the remaining players. They found that frequent headers showed brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury (TBI).
The findings are especially concerning given that soccer is the world's most popular sport with popularity growing in the U.S., especially among children. Of the 18 million Americans who play soccer, 78 percent are under the age of eighteen. Soccer balls are known to travel at speeds as high as 34 miles per hour during recreational play, and more than twice that during professional play.
After confirming the potentially damaging impact of frequent heading, "Our goal was to determine if there is a threshold level for heading frequency that, when surpassed, resulted in detectable brain injury," said lead author Michael Lipton, M.D., Ph.D., director of Einstein's Gruss Magnetic Resonance Research Center and medical director of MRI services at Montefiore. Further analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study exceeded that number, researchers observed significant injury.
"While heading a ball 1,000 or 1,500 times a year may seem high to those who don't participate in the sport, it only amounts to a few times a day for a regular player," observed Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences, and of the Dominick P. Purpura Department of Neuroscience at Einstein.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain," said Dr. Lipton. "But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells."
Researchers identified five areas, in the frontal lobe (behind the forehead) and in the temporo-occipital region (the bottom-rear areas) of the brain that were affected by frequent heading – areas that are responsible for attention, memory, executive functioning and higher-order visual functions. In a related study, Dr. Lipton and colleague Molly Zimmerman, Ph.D., assistant professor in the Saul R. Korey Department of Neurology at Einstein, gave the same 38 amateur soccer players tests designed to assess their neuropsychological function. Players with the highest annual heading frequency performed worse on tests of verbal memory and psychomotor speed (activities that require mind-body coordination, like throwing a ball) relative to their peers.
"These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency," Dr. Lipton said. "These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players."
Heading is an essential part of soccer and is unlikely to be eliminated from practice or play. As there appears to be a safe range for heading frequency, additional research can help refine this number, which can then be used to establish heading guidelines. As in other sports, the frequency of potentially harmful actions in practice and games could be monitored and restricted based on confirmed unsafe exposure thresholds.
"In the past, pitchers in Little League Baseball sustained shoulder injuries at a rate that was alarming," Dr. Lipton noted. "But ongoing research has helped shape various approaches, including limits on the amount of pitching a child performs, which have substantially reduced the incidence of these injuries."
"Brain injury due to heading in children, if we confirm that it occurs, may not show up on our radar because the impairment will not be immediate and can easily be attributed to other causes like ADHD or learning disabilities," continued Dr. Lipton. "We, including the agencies that supervise and encourage soccer play, need to do the further research to precisely define the impact of excessive heading on children and adults in order to develop parameters within which soccer play will be safe over the long term."
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Heading in Soccer—Could It Lead to Brain Injury?
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Could heading the ball in soccer lead to degenerative brain disease, like that seen in athletes in other sports? That's the question addressed by a review in the January issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.
As yet there's not clear evidence to link heading to short- or long-term brain injury, according to Dr Alejandro M. Spiotta of the Cleveland Clinic and colleagues. However, while research is ongoing, they stress the need for proper heading technique at all levels of organized soccer.
New Review of Evidence on Heading and Brain Injury Risk in Soccer
Soccer (called football outside the United States) is the only sport in which players use their unprotected heads to intentionally deflect, stop, or redirect the ball. Headed balls travel at high velocity both before and after impact, raising concerns about possible traumatic injury.
In 2002, English footballer Jeffrey Astle, known as a "formidable header," died with degenerative brain disease. The damage was consistent with chronic traumatic encephalopathy (CTE): a progressive neurodegenerative disease caused by repeated brain injury, seen in American football players and other athletes. Those reports have prompted concerns about similar risks in soccer players.
Although concussions are common in soccer, they more often result from the head striking another player or the goalpost, rather than heading the ball. But there's still concern about long-term injury related to repetitive trauma from heading.
Detailed biomechanical studies have been performed, showing that heading is a complex task in which significant energy is absorbed by the head. Emphasizing the importance of proper heading technique, studies have shown that anticipation and "pre-tensing" of the neck muscles play a key role in absorbing and redirecting the impact of a headed ball.
Pending Further Research, Emphasis on Proper Heading Technique
Older studies reported symptoms related to heading ("footballers' migraine"), but more recent research has not confirmed those effects. One factor may be the introduction of newer soccer balls that don't absorb moisture—unlike the leather balls used in Jeffrey Astle's day.
Soft headgear has been suggested to protect against soccer-related head injuries, although studies have questioned the protective benefits. There are even concerns that wearing headgear might even lead to increased injury risk, if players develop a false sense of security.
For now, the data on heading and brain injury "leave us somewhat in the grey zone," according to Dr Spiotta and colleagues. While it's reassuring that there's no clear link to CTE, the potential for long-term brain injury remains. "Even if the cognitive impairment were to be mild, it would still present a major medical and public health concern because of the massive volume of soccer players worldwide," the researchers write. "Any possible detrimental effect…may only become clinically evident decades in the future."
Dr Spiotta and coauthors emphasize the need for further research—including autopsy studies of players in the "light ball" era—to see if there is any similarity to the patterns of brain injury seen in CTE. Meanwhile, "Proper heading technique should continue to be stressed at all levels of play." The authors also highlight the importance of using an age-appropriate ball size for younger soccer players, as they develop the neck strength and posture control needed for proper heading technique.
Ω
Could heading the ball in soccer lead to degenerative brain disease, like that seen in athletes in other sports? That's the question addressed by a review in the January issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.
As yet there's not clear evidence to link heading to short- or long-term brain injury, according to Dr Alejandro M. Spiotta of the Cleveland Clinic and colleagues. However, while research is ongoing, they stress the need for proper heading technique at all levels of organized soccer.
New Review of Evidence on Heading and Brain Injury Risk in Soccer
Soccer (called football outside the United States) is the only sport in which players use their unprotected heads to intentionally deflect, stop, or redirect the ball. Headed balls travel at high velocity both before and after impact, raising concerns about possible traumatic injury.
In 2002, English footballer Jeffrey Astle, known as a "formidable header," died with degenerative brain disease. The damage was consistent with chronic traumatic encephalopathy (CTE): a progressive neurodegenerative disease caused by repeated brain injury, seen in American football players and other athletes. Those reports have prompted concerns about similar risks in soccer players.
Although concussions are common in soccer, they more often result from the head striking another player or the goalpost, rather than heading the ball. But there's still concern about long-term injury related to repetitive trauma from heading.
Detailed biomechanical studies have been performed, showing that heading is a complex task in which significant energy is absorbed by the head. Emphasizing the importance of proper heading technique, studies have shown that anticipation and "pre-tensing" of the neck muscles play a key role in absorbing and redirecting the impact of a headed ball.
Pending Further Research, Emphasis on Proper Heading Technique
Older studies reported symptoms related to heading ("footballers' migraine"), but more recent research has not confirmed those effects. One factor may be the introduction of newer soccer balls that don't absorb moisture—unlike the leather balls used in Jeffrey Astle's day.
Soft headgear has been suggested to protect against soccer-related head injuries, although studies have questioned the protective benefits. There are even concerns that wearing headgear might even lead to increased injury risk, if players develop a false sense of security.
For now, the data on heading and brain injury "leave us somewhat in the grey zone," according to Dr Spiotta and colleagues. While it's reassuring that there's no clear link to CTE, the potential for long-term brain injury remains. "Even if the cognitive impairment were to be mild, it would still present a major medical and public health concern because of the massive volume of soccer players worldwide," the researchers write. "Any possible detrimental effect…may only become clinically evident decades in the future."
Dr Spiotta and coauthors emphasize the need for further research—including autopsy studies of players in the "light ball" era—to see if there is any similarity to the patterns of brain injury seen in CTE. Meanwhile, "Proper heading technique should continue to be stressed at all levels of play." The authors also highlight the importance of using an age-appropriate ball size for younger soccer players, as they develop the neck strength and posture control needed for proper heading technique.
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Friday, November 11, 2011
Soccer: the effects of articular cartilage injury and degeneration in soccer players.
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More than 300 million play soccer across the globe and while the game is one of fast footwork, two organizations are trying to make sure these athletes stay on their feet. Fédération Internationale de Football Association (FIFA) and International Cartilage Repair Society (ICRS) have teamed up on a special supplement of Cartilage (published by SAGE) that examines the effects of articular cartilage injury and degeneration in soccer players.
"This issue provides a compact reference for players, coaches, medical staff, and researchers working with football players," wrote editors Kai Mithoefer, Lars Peterson, Daniel Saris, Bert Mandelbaum, and Jiri Dvorák. "Furthermore, it intends to act as a catalyst for the advancement of science and education of cartilage injury in soccer."
This supplement builds upon FIFA's successful 11+ program that is an easy-to-follow, standardized warm-up routine that helps all levels of soccer athletes reduce injury. In keeping with the theme, Cartilage features 11 articles that provide a comprehensive overview of current knowledge around cartilage injury, prevention strategies and treatment options.
The introduction written by the co-editors is available free for a limited time at: http://car.sagepub.com/content/3/1_suppl/4S.full.pdf+html
The special supplement of Cartilage features the following contributions:
• Editorial: "Special Issue on Articular Cartilage Injury in the Football (Soccer) Player" by Kai Mithoefer, Lars Peterson, Daniel Saris, Bert Mandelbaum, and Jiri Dvorák
• Executive Summary: "'Cartilage Issues in Football (Soccer): An Executive Summary of the Fédération Internationale de Football Association (FIFA)/International Cartilage Repair Society (ICRS) Initiative" by Bert Mandelbaum
• "Scientific Evidence Base for Cartilage Injury and Repair in the Athlete" by Matthias Steinwachs, Lars Engebretsen, and Robert H. Brophy
• "Clinical and Basic Science of Cartilage Injury and Arthritis in the Soccer Athlete" by Hannah Hoeun Lee and Constance R. Chu
• "Microfracture in Football (Soccer) Players: A Case Series of Professional Athletes and Systematic Review" by Kai Mithoefer and Richard J. Steadman
• "Osteochondral Autograft and Mosaicplasty in the Football Athlete" by Gergely Pánics, Eszter Baló, Gábor Vásárhelyi, Tamás Gál, and László Hangody
• "Osteochondral and Meniscal Allograft Transplantation in the Football (Soccer) Player" by Simon Görtz, Riley J. Williams, Wayne Gersoff, and William D. Bugbee
• "Evolution and Current Role of Autologous Chondrocyte Implantation for Treatment of Articular Cartilage Defects in the Football (Soccer) Player" by Kai Mithoefer, Lars Peterson, Daniel B.F. Saris, and Bert R. Mandelbaum
• "Management of the Retired Athlete with Osteoarthritis of the Knee" by Donald T. Kirkendall and William E. Garrett, Jr.
• "Rehabilitation after Articular Cartilage Repair of the Knee in the Football Player" by Karen Hambly, Holly Jacinda Silvers and Matthias Steinwachs
• "Return to Sports after Articular Cartilage Repair in the Football Player" by Kai Mithoefer and Stefano Della Villa
• "New Frontiers for Cartilage Repair and Protection" by Kenneth Zaslav, Tim McAdams, Jason M. Scopp, Jason Theodosakis, Vivek Mahajan and Alberto Gobbi
• "Cartilage Repair in Football (Soccer) Athletes: What Evidence Leads to Which Treatment? A Critical Review of the Literature" by Joris EJ Bekkers, Tommy S. de Windt, Mats Brittberg and Daniel BF Saris
More than 300 million play soccer across the globe and while the game is one of fast footwork, two organizations are trying to make sure these athletes stay on their feet. Fédération Internationale de Football Association (FIFA) and International Cartilage Repair Society (ICRS) have teamed up on a special supplement of Cartilage (published by SAGE) that examines the effects of articular cartilage injury and degeneration in soccer players.
"This issue provides a compact reference for players, coaches, medical staff, and researchers working with football players," wrote editors Kai Mithoefer, Lars Peterson, Daniel Saris, Bert Mandelbaum, and Jiri Dvorák. "Furthermore, it intends to act as a catalyst for the advancement of science and education of cartilage injury in soccer."
This supplement builds upon FIFA's successful 11+ program that is an easy-to-follow, standardized warm-up routine that helps all levels of soccer athletes reduce injury. In keeping with the theme, Cartilage features 11 articles that provide a comprehensive overview of current knowledge around cartilage injury, prevention strategies and treatment options.
The introduction written by the co-editors is available free for a limited time at: http://car.sagepub.com/content/3/1_suppl/4S.full.pdf+html
The special supplement of Cartilage features the following contributions:
• Editorial: "Special Issue on Articular Cartilage Injury in the Football (Soccer) Player" by Kai Mithoefer, Lars Peterson, Daniel Saris, Bert Mandelbaum, and Jiri Dvorák
• Executive Summary: "'Cartilage Issues in Football (Soccer): An Executive Summary of the Fédération Internationale de Football Association (FIFA)/International Cartilage Repair Society (ICRS) Initiative" by Bert Mandelbaum
• "Scientific Evidence Base for Cartilage Injury and Repair in the Athlete" by Matthias Steinwachs, Lars Engebretsen, and Robert H. Brophy
• "Clinical and Basic Science of Cartilage Injury and Arthritis in the Soccer Athlete" by Hannah Hoeun Lee and Constance R. Chu
• "Microfracture in Football (Soccer) Players: A Case Series of Professional Athletes and Systematic Review" by Kai Mithoefer and Richard J. Steadman
• "Osteochondral Autograft and Mosaicplasty in the Football Athlete" by Gergely Pánics, Eszter Baló, Gábor Vásárhelyi, Tamás Gál, and László Hangody
• "Osteochondral and Meniscal Allograft Transplantation in the Football (Soccer) Player" by Simon Görtz, Riley J. Williams, Wayne Gersoff, and William D. Bugbee
• "Evolution and Current Role of Autologous Chondrocyte Implantation for Treatment of Articular Cartilage Defects in the Football (Soccer) Player" by Kai Mithoefer, Lars Peterson, Daniel B.F. Saris, and Bert R. Mandelbaum
• "Management of the Retired Athlete with Osteoarthritis of the Knee" by Donald T. Kirkendall and William E. Garrett, Jr.
• "Rehabilitation after Articular Cartilage Repair of the Knee in the Football Player" by Karen Hambly, Holly Jacinda Silvers and Matthias Steinwachs
• "Return to Sports after Articular Cartilage Repair in the Football Player" by Kai Mithoefer and Stefano Della Villa
• "New Frontiers for Cartilage Repair and Protection" by Kenneth Zaslav, Tim McAdams, Jason M. Scopp, Jason Theodosakis, Vivek Mahajan and Alberto Gobbi
• "Cartilage Repair in Football (Soccer) Athletes: What Evidence Leads to Which Treatment? A Critical Review of the Literature" by Joris EJ Bekkers, Tommy S. de Windt, Mats Brittberg and Daniel BF Saris
Wednesday, September 7, 2011
White favoritism by Major League umps lowers minority pitcher performance, pay
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When it comes to Major League Baseball's pitchers, the more strikes, the better. But what if white umpires call strikes more often for white pitchers than for minority pitchers?
New research findings provide an answer. Analysis of 3.5 million pitches from 2004 to 2008 found that minority pitchers scale back their performance to overcome racial/ethnic favoritism toward whites by MLB home plate umpires, said economist Johan Sulaeman, a financial economist at Southern Methodist University in Dallas and a study author.
The study found that minority pitchers reacted to umpire bias by playing it safe with the pitches they throw in a way that actually harmed their performance and statistics, said Sulaeman, a labor and discrimination expert.
Specifically, minority pitchers limited the umpires' discretion to call their pitch a "ball" by throwing squarely across the plate in the strike zone more often. Unfortunately for the pitcher, such throws are also easier for batters to hit.
The finding builds on an earlier study that discovered Major League Baseball's home plate umpires called strikes more often for pitchers in their same ethnic group — except when the plate was electronically monitored by cameras, Sulaeman said.
While the earlier finding surprised the researchers, they said, the latest results are even more surprising.
Since most MLB umpires are white, the overall effect is that umpire bias pushes performance measures of minorities downward, said Sulaeman, an expert in labor economics and discrimination.
The findings have important implications for measuring the extent of discrimination not only in baseball, but also in labor markets generally, say the authors.
"In MLB, as in so many other fields of endeavor, power belongs disproportionately to members of the majority — white — group," the authors write.
Findings draw on analysis of pitching in QuesTec-monitored parks
Sulaeman and his co-authors analyzed 3.5 million pitches by Major League Baseball pitchers from 2004 to 2008. All parks are now monitored, but during those four years about one-third of major league ballparks were monitored with computers and cameras to check the accuracy of the umpires' ball and strike calls.
Four cameras tracked and recorded the location of each pitch, with umpires and pitchers aware that QuesTec was the primary mechanism for gauging umpire performance. MLB considers an ump's performance sub-standard if more than 10 percent of his calls differ from QuesTec.
Of the 3.5 million pitches, umpire and pitcher were the same race — usually white — for about two-thirds of the 1.89 million pitches that were called strikes or balls. About 89 percent of umpires and 70 percent of pitchers were white.
The researchers looked not only at the race of umpires, pitchers and batters, but also: effects for each pitcher, umpire and batter; presence or absence of QuesTec; importance of the at-bat; when the pitch would terminate the at-bat; whether the pitch came early or later in the game; importance of the game; racial demographics of the neighborhood around the park; umpire age and experience; pitch characteristics, including horizontal pitch distance and pitch height; and whether the throw was a fastball, curveball, slider or cutter.
The study controlled for inning, pitch count, pitcher score advantage and whether the pitcher was playing at home or visiting.
The study, "Strike Three: Discrimination, Incentives, and Evaluation," is published in the current issue of the scholarly journal The American Economic Review.
In addition to Sulaeman, co-authors were Christopher A. Parsons, University of North Carolina at Chapel Hill; Michael C. Yates, Auburn University; and Daniel S. Hamermesh, University of Texas at Austin.
Findings: Minimal direct impact, but significant indirect influence
The researchers found:
In non-monitored parks, the percentage of called pitches that are strikes is higher when the race of both umpire and pitcher match than when it does not. This is true not only of whites, but also Hispanics and blacks.
In QuesTec parks, if the race of the pitcher and umpire match, the likelihood that a called pitch is ruled a strike is reduced by more than one percentage point relative to the same setup in non-QuesTec parks. This implies umpires implicitly allow their apparent favoritism to be expressed when not being monitored, the study authors say.
Implicit monitoring — for example, an important pitch viewed by a big crowd — also dramatically alters umpire behavior. On the other hand, white and minority umpires at poorly attended games appear to favor pitchers of the same race by calling more strikes.
Umpires favor pitchers of the same race only when the pitch won't terminate the batter's plate appearance.
Little evidence was found to indicate the umpire is influenced by the race of either the batter or the catcher.
A higher strike percentage showed umpires exhibited same-race favoritism in non-QuesTec parks. A lower strike percentage indicated negative bias toward pitchers of different races in QuesTec parks.
There is some weak evidence that bias is more likely among younger and less experienced umpires.
Favoritism was a significant factor for pitches thrown to the edge of the strike zone — where umpires have the most discretion — but not for pitches inside or outside the strike zone. In QuesTec parks, the umpire and pitcher having the same race has virtually no effect on pitch location. In non-QuesTec parks, pitches to the edges significantly increase when umpire and pitcher share the same race. The finding suggests pitchers gamble on the fact that this region can reasonably be called as either balls or strikes and therefore offers them an advantage.
In QuesTec parks, matched race is associated with a slight preference for hard-to-hit and hard-to-call curveball pitches. In non-QuesTec parks, that preference quadruples.
The researchers concluded:
The direct effects on pitch outcomes are small. The indirect effect on players' strategies may have larger impacts on the outcomes of plate appearances and games.
From the starting pitcher's perspective, a racial match with the umpire helped his statistics by yielding fewer earned runs, fewer hits and fewer home runs.
Because the majority of umpires are white, teams with minority pitchers have a distinct disadvantage in non-monitored parks.
There is no evidence that visiting managers adjusted their pitching lineups to minimize exposure of their minority pitchers to the subjective bias of a white umpire.
In parks without QuesTec, pitchers of the same race threw pitches that allowed umpires the most discretion, apparently to maximize their advantage stemming from the umpires' favoritism.
A batter who swings is less likely to get a hit when the umpire and pitcher match.
Applying the effects of favoritism, and given that the average salary of starting pitchers in MLB was $4.8 million in 2006, the findings suggest minority pitchers were underpaid relative to white pitchers by between $50,000 and $400,000 a year.
"If a pitcher expects favoritism, he will incorporate this advantage into his strategy, perhaps throwing pitches that allow the umpire more discretion," the authors write. "If the batter expects such pitches to be called strikes, he is forced to swing at worse pitches, which reduces the likelihood of getting a hit."
Not just Major League Baseball; a factor in all work environments
How many minority pitchers have had their pitching records diminished by this phenomenon is impossible to say, Sulaeman said, adding that one can only guess at the impact over decades of professional baseball. But discovery of the indirect effect of racial bias in MLB pointedly demonstrates how discrimination alters the behavior of a discriminated group, say the authors.
In any workplace where pay is based on measured productivity, the findings of small direct and larger indirect effects of favoritism and negative bias have important implications for measuring the extent of wage discrimination not only in baseball, but also in labor markets generally, say the authors.
Supervisory racial bias must be accounted for when generating measures of wage discrimination, the authors conclude.
The researchers' earlier analysis of the data found that ethnic bias is virtually eliminated when an umpire knows his calls are being monitored with video cameras to check for accuracy.
"The good news is that all ballparks are now equipped with this technology, likely eliminating this subconscious bias," said Sulaeman, assistant professor of finance in SMU's Cox School.
Monitoring suppresses bias when evaluators are observed for bias
That isn't the case, however, in other workplaces, where monitoring is not the norm, he said. As a result, supervisors have ample opportunity to subconsciously evaluate those of a different race more negatively, he said. Supervisors may be less prone to this subconscious bias if they know they are being monitored.
"When their decisions matter more, and when evaluators are themselves more likely to be evaluated by others, our results suggest that these preferences no longer manifest themselves," the authors say. — Margaret Allen
When it comes to Major League Baseball's pitchers, the more strikes, the better. But what if white umpires call strikes more often for white pitchers than for minority pitchers?
New research findings provide an answer. Analysis of 3.5 million pitches from 2004 to 2008 found that minority pitchers scale back their performance to overcome racial/ethnic favoritism toward whites by MLB home plate umpires, said economist Johan Sulaeman, a financial economist at Southern Methodist University in Dallas and a study author.
The study found that minority pitchers reacted to umpire bias by playing it safe with the pitches they throw in a way that actually harmed their performance and statistics, said Sulaeman, a labor and discrimination expert.
Specifically, minority pitchers limited the umpires' discretion to call their pitch a "ball" by throwing squarely across the plate in the strike zone more often. Unfortunately for the pitcher, such throws are also easier for batters to hit.
The finding builds on an earlier study that discovered Major League Baseball's home plate umpires called strikes more often for pitchers in their same ethnic group — except when the plate was electronically monitored by cameras, Sulaeman said.
While the earlier finding surprised the researchers, they said, the latest results are even more surprising.
Since most MLB umpires are white, the overall effect is that umpire bias pushes performance measures of minorities downward, said Sulaeman, an expert in labor economics and discrimination.
The findings have important implications for measuring the extent of discrimination not only in baseball, but also in labor markets generally, say the authors.
"In MLB, as in so many other fields of endeavor, power belongs disproportionately to members of the majority — white — group," the authors write.
Findings draw on analysis of pitching in QuesTec-monitored parks
Sulaeman and his co-authors analyzed 3.5 million pitches by Major League Baseball pitchers from 2004 to 2008. All parks are now monitored, but during those four years about one-third of major league ballparks were monitored with computers and cameras to check the accuracy of the umpires' ball and strike calls.
Four cameras tracked and recorded the location of each pitch, with umpires and pitchers aware that QuesTec was the primary mechanism for gauging umpire performance. MLB considers an ump's performance sub-standard if more than 10 percent of his calls differ from QuesTec.
Of the 3.5 million pitches, umpire and pitcher were the same race — usually white — for about two-thirds of the 1.89 million pitches that were called strikes or balls. About 89 percent of umpires and 70 percent of pitchers were white.
The researchers looked not only at the race of umpires, pitchers and batters, but also: effects for each pitcher, umpire and batter; presence or absence of QuesTec; importance of the at-bat; when the pitch would terminate the at-bat; whether the pitch came early or later in the game; importance of the game; racial demographics of the neighborhood around the park; umpire age and experience; pitch characteristics, including horizontal pitch distance and pitch height; and whether the throw was a fastball, curveball, slider or cutter.
The study controlled for inning, pitch count, pitcher score advantage and whether the pitcher was playing at home or visiting.
The study, "Strike Three: Discrimination, Incentives, and Evaluation," is published in the current issue of the scholarly journal The American Economic Review.
In addition to Sulaeman, co-authors were Christopher A. Parsons, University of North Carolina at Chapel Hill; Michael C. Yates, Auburn University; and Daniel S. Hamermesh, University of Texas at Austin.
Findings: Minimal direct impact, but significant indirect influence
The researchers found:
In non-monitored parks, the percentage of called pitches that are strikes is higher when the race of both umpire and pitcher match than when it does not. This is true not only of whites, but also Hispanics and blacks.
In QuesTec parks, if the race of the pitcher and umpire match, the likelihood that a called pitch is ruled a strike is reduced by more than one percentage point relative to the same setup in non-QuesTec parks. This implies umpires implicitly allow their apparent favoritism to be expressed when not being monitored, the study authors say.
Implicit monitoring — for example, an important pitch viewed by a big crowd — also dramatically alters umpire behavior. On the other hand, white and minority umpires at poorly attended games appear to favor pitchers of the same race by calling more strikes.
Umpires favor pitchers of the same race only when the pitch won't terminate the batter's plate appearance.
Little evidence was found to indicate the umpire is influenced by the race of either the batter or the catcher.
A higher strike percentage showed umpires exhibited same-race favoritism in non-QuesTec parks. A lower strike percentage indicated negative bias toward pitchers of different races in QuesTec parks.
There is some weak evidence that bias is more likely among younger and less experienced umpires.
Favoritism was a significant factor for pitches thrown to the edge of the strike zone — where umpires have the most discretion — but not for pitches inside or outside the strike zone. In QuesTec parks, the umpire and pitcher having the same race has virtually no effect on pitch location. In non-QuesTec parks, pitches to the edges significantly increase when umpire and pitcher share the same race. The finding suggests pitchers gamble on the fact that this region can reasonably be called as either balls or strikes and therefore offers them an advantage.
In QuesTec parks, matched race is associated with a slight preference for hard-to-hit and hard-to-call curveball pitches. In non-QuesTec parks, that preference quadruples.
The researchers concluded:
The direct effects on pitch outcomes are small. The indirect effect on players' strategies may have larger impacts on the outcomes of plate appearances and games.
From the starting pitcher's perspective, a racial match with the umpire helped his statistics by yielding fewer earned runs, fewer hits and fewer home runs.
Because the majority of umpires are white, teams with minority pitchers have a distinct disadvantage in non-monitored parks.
There is no evidence that visiting managers adjusted their pitching lineups to minimize exposure of their minority pitchers to the subjective bias of a white umpire.
In parks without QuesTec, pitchers of the same race threw pitches that allowed umpires the most discretion, apparently to maximize their advantage stemming from the umpires' favoritism.
A batter who swings is less likely to get a hit when the umpire and pitcher match.
Applying the effects of favoritism, and given that the average salary of starting pitchers in MLB was $4.8 million in 2006, the findings suggest minority pitchers were underpaid relative to white pitchers by between $50,000 and $400,000 a year.
"If a pitcher expects favoritism, he will incorporate this advantage into his strategy, perhaps throwing pitches that allow the umpire more discretion," the authors write. "If the batter expects such pitches to be called strikes, he is forced to swing at worse pitches, which reduces the likelihood of getting a hit."
Not just Major League Baseball; a factor in all work environments
How many minority pitchers have had their pitching records diminished by this phenomenon is impossible to say, Sulaeman said, adding that one can only guess at the impact over decades of professional baseball. But discovery of the indirect effect of racial bias in MLB pointedly demonstrates how discrimination alters the behavior of a discriminated group, say the authors.
In any workplace where pay is based on measured productivity, the findings of small direct and larger indirect effects of favoritism and negative bias have important implications for measuring the extent of wage discrimination not only in baseball, but also in labor markets generally, say the authors.
Supervisory racial bias must be accounted for when generating measures of wage discrimination, the authors conclude.
The researchers' earlier analysis of the data found that ethnic bias is virtually eliminated when an umpire knows his calls are being monitored with video cameras to check for accuracy.
"The good news is that all ballparks are now equipped with this technology, likely eliminating this subconscious bias," said Sulaeman, assistant professor of finance in SMU's Cox School.
Monitoring suppresses bias when evaluators are observed for bias
That isn't the case, however, in other workplaces, where monitoring is not the norm, he said. As a result, supervisors have ample opportunity to subconsciously evaluate those of a different race more negatively, he said. Supervisors may be less prone to this subconscious bias if they know they are being monitored.
"When their decisions matter more, and when evaluators are themselves more likely to be evaluated by others, our results suggest that these preferences no longer manifest themselves," the authors say. — Margaret Allen
Tuesday, September 6, 2011
Nearly Half of Runners May Be Drinking Too Much During Races
Ω
Nearly half of recreational runners may be drinking too much fluid during races, according to a survey of runners by Loyola University Health System researchers.
Expert guidelines recommend runners drink only when thirsty. But the Loyola survey found that 36.5 percent of runners drink according to a preset schedule or to maintain a certain body weight and 8.9 percent drink as much as possible.
Nearly a third of runners (29.6 percent) incorrectly believe they need to ingest extra salt while running. And more than half (57.6 percent) say they drink sports drinks because the drinks have electrolytes that prevent low blood sodium. In fact, the main cause of low sodium in runners is drinking too much water or sports drinks. "Many athletes hold unscientific views regarding the benefits of different hydration practices," researchers concluded. The study was published in the June, 2011, issue of the British Journal of Sports Medicine.
Drinking too much fluid while running can cause a potentially fatal condition called exercise-associated hyponatremia. It occurs when runners drink even when they are not thirsty. Drinking too much during exercise can dilute the sodium content of blood to abnormally low levels.
Drinking only when thirsty will prevent overconsumption of fluids. "It's the safest known way to hydrate during endurance exercise," said Loyola sports medicine physician Dr. James Winger, first author of the study. Symptoms of hyponatremia can include nausea, vomiting, headache, confusion, loss of energy, muscle weakness, spasms or cramps. In extreme cases, the condition can lead to seizures, unconsciousness and coma.
In recent years, there have been 12 documented and 8 suspected runners' deaths from hyponatremia, said Loyola exercise physiologist Lara Dugas, PhD, a co-author of the study.
The International Marathon Medical Directors Association recommends that runners drink only when thirsty. The Loyola researchers surveyed 197 runners who competed in the 2009 Westchester, Il. Veterans Day 10K and 5K runs and two other runs on Chicago's lakefront.
The 91 male runners, on average, had been running for 13 years and had run an average of 1.9 10K races and 0.9 marathons. The 106 women, on average, had been running 8.3 years and had run an average of 1.3 10K races and 0.7 marathons.
In the survey, the runners generally said advertising by sports drink manufacturers had little or no influence on their beliefs. But the behaviors of many of the runners indicate otherwise.
During the 1980s and 1990s, sports drinks ads warned about the supposed dangers of dehydration, and recommend that runners drink as much as 1.2 liters (five cups) per hour. Sports drink manufacturers generally have stopped promoting overdrinking. But the unscientific beliefs persist that runners should drink as much as they can or according to a preset schedule.
"We have been trained to believe that dehydration is a complication of endurance exercise," Dugas said. "But in fact, the normal physiological response to exercise is to lose a small amount of fluid. Runners should expect to lose several pounds during runs, and not be alarmed."
Nearly half of recreational runners may be drinking too much fluid during races, according to a survey of runners by Loyola University Health System researchers.
Expert guidelines recommend runners drink only when thirsty. But the Loyola survey found that 36.5 percent of runners drink according to a preset schedule or to maintain a certain body weight and 8.9 percent drink as much as possible.
Nearly a third of runners (29.6 percent) incorrectly believe they need to ingest extra salt while running. And more than half (57.6 percent) say they drink sports drinks because the drinks have electrolytes that prevent low blood sodium. In fact, the main cause of low sodium in runners is drinking too much water or sports drinks. "Many athletes hold unscientific views regarding the benefits of different hydration practices," researchers concluded. The study was published in the June, 2011, issue of the British Journal of Sports Medicine.
Drinking too much fluid while running can cause a potentially fatal condition called exercise-associated hyponatremia. It occurs when runners drink even when they are not thirsty. Drinking too much during exercise can dilute the sodium content of blood to abnormally low levels.
Drinking only when thirsty will prevent overconsumption of fluids. "It's the safest known way to hydrate during endurance exercise," said Loyola sports medicine physician Dr. James Winger, first author of the study. Symptoms of hyponatremia can include nausea, vomiting, headache, confusion, loss of energy, muscle weakness, spasms or cramps. In extreme cases, the condition can lead to seizures, unconsciousness and coma.
In recent years, there have been 12 documented and 8 suspected runners' deaths from hyponatremia, said Loyola exercise physiologist Lara Dugas, PhD, a co-author of the study.
The International Marathon Medical Directors Association recommends that runners drink only when thirsty. The Loyola researchers surveyed 197 runners who competed in the 2009 Westchester, Il. Veterans Day 10K and 5K runs and two other runs on Chicago's lakefront.
The 91 male runners, on average, had been running for 13 years and had run an average of 1.9 10K races and 0.9 marathons. The 106 women, on average, had been running 8.3 years and had run an average of 1.3 10K races and 0.7 marathons.
In the survey, the runners generally said advertising by sports drink manufacturers had little or no influence on their beliefs. But the behaviors of many of the runners indicate otherwise.
During the 1980s and 1990s, sports drinks ads warned about the supposed dangers of dehydration, and recommend that runners drink as much as 1.2 liters (five cups) per hour. Sports drink manufacturers generally have stopped promoting overdrinking. But the unscientific beliefs persist that runners should drink as much as they can or according to a preset schedule.
"We have been trained to believe that dehydration is a complication of endurance exercise," Dugas said. "But in fact, the normal physiological response to exercise is to lose a small amount of fluid. Runners should expect to lose several pounds during runs, and not be alarmed."
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