Movement and Decision Making: Predictors of Success

Talent identification in soccer is a difficult process. At times it seems that it is more of an art than a science. Coaches consider a wide number of factors when assessing a player’s talent and potential for success. Physical characteristics, technical abilities and an understating of tactical concepts are all components of a talented player. A group of researchers from the University of Groningen (Groningen, The Netherlands) has examined this last characteristic as part of player’s development and as a predictor of future success. They found that advancement from the youth to professional level is heavily dependant on the player’s ability to understand tactical concepts AND put them into practice.

Researchers administered a self-assessed, tactical skills inventory test to a group of elite youth players. All of the players were members of various Dutch premier league developmental programs. At the time the test was administered, the players ranged in age from 16-18 years. Several years later, after they had reached at least 21 years of age, they were categorized into two groups – those who were playing professionally for a premier- or national-level team and those who were playing with an amateur club.

The tactical skills inventory test examined four tactical characteristics 1) knowing about ball actions, 2) knowing about others on the field, 3) positioning and deciding and 4) acting on changing situations.

The primary finding of the study was a large difference in test scores between the players who attained professional and amateur status. The professional players scored significantly higher on the positioning and deciding characteristic. In fact, those players who had the highest scores in this characteristic were nearly 7 times more likely to have reached the professional level than those who scored lowest.

Thus, the ability to be in the right place at the right time and to make correct decisions is the most important factor in determining future success.

At the time the test was administered, all players had a considerable amount of experience and had trained and competed at a high level. Based on their test scores, they all know the rules of the game and understand their teammate’s responsibilities, their opponent’s strategies and movements of the ball. However, it is “procedural knowledge” or translating knowledge into action that separates potential success. That is, successful players both comprehend tactical issues AND carry out the correct actions.

On the downside, this study focused on elite youth players who were nearing the transition from youth to adult amateur and professional programs (U18). The investigators point out that generalizing the results to younger or less skilled players may be difficult. However, it is reasonable to suggest that coaches of younger players (e.g. U16) foster the ability to understand AND apply tactical concepts. Developing both tactical knowledge and decision making can lead to future success.

The results of this study suggests that positioning and deciding is that tactical skill that best predicts future success to youth players. They also suggest that coaches pay attention to this aspect of each player’s games. It should be taken into account with identifying talented players. It is also a characteristic that should be developed during the adolescent years.

Reference:

Kannekens R, Elferink-Gemser MT, Visscher C (2010) Positioning and deciding: Key factors for talent develpment in soccer. Scandinavian Journal of Medicine and Science in Sports, DOI: 10.1111/j.1600-0838.2010.01104.x
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Running with the Ball: How Much, How Often?

Several research studies have documented the movement patterns of both professional and youth players. The distances covered, movement speeds and directional changes during a match are all fairly well understood. However, less is known about the characteristics of ball possession during a match. How much time is spent with the ball? What are the characteristics of each possession such as the number of touches, speed when running with the ball and space created? These questions are addressed in a new study published in the Journal of Sports Sciences. Chris Carling, Science Director of Lille Football Club, describes the activity profiles of running with the ball in French professional players. He shows some very interesting patterns of ball possession and how they vary by position.

A total of 30 French League 1 matches were analyzed over a period of two seasons. A computerized tracking system was used to characterize the movement patterns of each player. Match analysis software was used to determine each player’s performance with the ball. These systems provide information about movement speeds, distances and direction as well as the characteristics of each possession.

The results show some interesting patterns. The total distance covered by these professional players was slightly more than11 km per match (nearly 7 miles). This is in line with what other researchers have reported. Central midfielders covered the most distance while central defenders covered the least (although the difference was only about 10%). Outside midfielders and forwards tend to sprint further than they jog whereas central defenders tend to do the opposite.

Players had, on average, 47 possessions per match. Central forwards had the fewest possessions (35) while outside defenders had the most (56).

Of the 11 km covered, only 191 m was run with the ball (1.7% of the total distance covered). This translates into about 53 sec of the match spent in possession of the ball (less than 1% of the time played). During each possession, the player covered 3-5 m, held on to the ball for slightly more than one second and averaged two touches per possession. Outside midfielders tended to hold on to the ball slightly longer than the other positions, covered more distance with the ball and took more touches per possession.

Players took possession of the ball with about 4m of space. Outside midfielders received the ball with more space (5m) while outside defenders had the least space (3m).

The average running speed when the player took possession was 10.3 km/hr and their speed during possession was12.9 km/hr (light speed). Peak speeds during possession reached nearly 25 km/hr (high speed / sprint). Thus, players generally received the ball while running, then accelerated before giving up possession.

When placing the results in the context of player training. Carling emphasizes four key concepts regarding player training. First, given that the movement patterns during the match vary by player position, fitness and technical training can be tailored for individual players based on the specific positional demands of the match.

Second, only a small percentage of the match is spent with the ball and the greatest percentage of movements with the ball are undertaken at a fairly high sunning velocity. This suggests that fitness training should be carried out both with and without the ball. Also, running with the ball during training could be performed at high speed to simulate match demands.

Third, the speed at which players receive the ball suggests that passing drills designed to improve first touch and ball control could be carried out while the player is moving not in a static position. Dribbling and ball control drills should be executed as both low and high speed. Again, emphasis could be placed on simulating match conditions.

Lastly, the importance of creating space and good ball technique should be emphasized in order to make the most of the limited time each player is in possession of the ball.

In addition to these recommendations and conclusions, this study emphasizes three additional points. First, one must realize that this study reports movement patterns and ball possession characteristics of high level professional players. Thus it is sometimes difficult to translate the results and recommendations directly to the youth game. However, the general concept of limited possessions and time spent with the ball over the course of a match is probably applicable to both youth and professional matches.

Second, the professionals clearly do not hold onto the ball for long periods nor do they do a lot of dribbling. They average 2 touches per possession. They are receiving or winning the ball then quickly giving it up. This emphasizes the need to train players in these sorts of possessions - developing the ability to make a successful pass quickly after receiving the ball.

The final point is that the professional players average 47 possessions per match and 2 touches per possession. This translates to around 90 touches per 90 min match. Given the skill level of youth players, the reduced length of matches and the fact that most players do not play the entire match, their average number of possessions and touches per match is probably on the order of 20 and 40. This stresses the importance of training sessions to develop technical skills. Drills and small-sided games offer players many touches, accomplished at varying pace and under varying levels of space or pressure. Certainly more than a few dozen touches are executed during a typical training session.

This study has clearly broadened our understanding of player movement patterns during competitive conditions. The results can be used to vary training sessions in order to meet the match demands of specific positions. Also, it emphasizes the need for specific training as opposed to matches for developing ball skills.

Reference:

Carling C (2010) Analysis of physical activity profiles when running with the ball in a professional soccer team. Journal of Sports Sciences, 28:319-326.
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Recreational Soccer: The Magic Pill for Adult Health?

Many adults are engaged in a never ending search for the “magic pill” that will improve their health and wellbeing. This is the focus of many fitness products and nutritional supplements that advertise extraordinary gains in health with little effort. Others spend countless hours pound away on the treadmill, stationary bicycle or elliptical machine in an effort to lose weight, improve fitness and avoid health complications. While we may never find that magic pill we may have found a balance between monotonous exercise and the lure of a quick fix. A recent research review argues that sedentary adults who participate in recreational soccer programs reap the same benefits as those who engage in more traditional exercise routines.

This post focuses on a review article by researchers at the University of Copenhagen. The article is a part a special issue of the Scandinavian Journal of Medicine and Science in Sports that is devoted to the health benefits of soccer. In weeks to come, we will be discussing other articles in this journal. For now, the focus is on adults and recreational soccer programs.

The researchers analyzed research studies focused on the health and fitness effects of recreational soccer. The approach they took was rather unique. Most agree that placing sedentary adults in ANY type of exercise program, including recreational soccer, will improve fitness and other health markers. In this review, the Copenhagen researchers also compared the effects of soccer to the effects of other types of exercise, specifically jogging, interval running and strength training.

In general, the studies examined sedentary adult subjects who participated in recreational soccer programs. The ages of the subjects were not specifically listed but were identified as “adults”. Most of the available studies used male subjects but a few focused on women. The programs lasted between 10 and 24 weeks and subjects typically played 3 times per week for 30-60 min per session. Training session usually involved small-sided games but some used 11v11 matches.

What follows is a summary of the overall findings and conclusions.

Fitness: Subject engaged in soccer training improved their VO2max by an average of 13%. Improvements were made using both full- and small-sided matches. When compared to jogging or interval running programs of similar training hours, the improvements in fitness via soccer were similar.

Cardiovascular Effects: Soccer training lead to reductions in resting blood pressure and resting heart rate. The effects on blood pressure were most pronounced in subjects with the highest initial levels. In addition, the researchers concluded that the improvements have significant health effects for the participants such as reduced risk for stroke and heart attack.

Blood lipids were also improved through soccer training. LDL cholesterol (bad cholesterol) was lowered and HDL cholesterol (the good type) was elevated after training. In addition, improved glucose tolerance and muscle enzyme levels in Type II diabetic patients occurred when soccer training was combined with nutritional advice. All of the changes due to recreational soccer participation were similar to those found using other exercise programs.


Body Composition: The soccer training programs show small reductions in body fat and increase in lean body mass. The changes in lean body mass reflect increases in muscle mass and muscle fiber hypertrophy. Such changes are not normally seen after jogging or interval running. Muscle fiber hypertrophy observed after soccer training (~15%) was nearly the same as that seen after weight training in men of similar age (~18%). Soccer also elicited changes in neuromuscular control that may improve balance and reduce the risk of falls and joint injuries.

Bone Mass: A few studies found that bone health was improved after soccer training. Bone mass in the legs, hip and lumbar spine were all increased. The changes were much greater than those that occurred after jogging and interval running and similar to weight training.

Perceived Effort: Perhaps one of the most important findings was that ratings of perceived exertion during soccer training were lower than those recorded during running. That is, when exercising at similar work rates and intensities, soccer participants felt a reduced sense of effort – they didn’t perceive themselves as working as hard as the runners. This may be linked to factors such as the focus and enjoyment of playing soccer and the social interactions with teammates. The more participants enjoy their exercise program, the greater their level of participation and the greater the health benefits.

Injury Risk: On the downside, the risk of injury may be somewhat greater in soccer programs that in other exercise programs - especially given the movement patterns and potential for contact injury. However, this is a difficult comparison to make since many of the risk injury studies don’t consider the intensity of the program. The Copenhagen researchers calculated that in the all of the studies reviewed,

Reference:

Krustrup P, Aagaard P, Nybo L, Peterson J, Mohr M, Bangsbo J (2010) Recreational football as a health promoting activity: A topical review. Scandinavian Journal of Medicine and Science in Sports, DOI: 10.1111/j.1600-0838.2010.01108.x
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Soccer is Good For Your Sleep

This website along with many other publications has listed the virtues of playing soccer. There is little doubt that soccer has some wonderful physical and social benefits for both recreational and competitive players. Development of fitness, strength endurance, self confidence, team work and focus are important traits that can be gained through the soccer environment. New research from Switzerland now adds better sleep to that list. It seems that competitive players get a more restful night’s sleep than their inactive counterparts.

The researchers from the University of Basel recruited male players from the junior division of the FC Concordia club. Non-players were selected from a pool of students within the same school that the FCB players attended. The age of the entire pool ranged from about 5-16 years. Over the course of the school term, all of the participants were given a series of questionnaires about their sleep patterns, sleep quality, daily mood and exercise participation.

A key difference that emerged was the amount of physical exercise performed by the two groups of subjects. The players averaged between 12 and 13 hours of activity per week while the non-players exercised for less than two hours weekly. Also, the players were described by the investigators as “intense” footballers and chronic exercisers.

The main findings of the study were the rather large differences in both the pattern and quality of sleep between the two groups of students. The players averaged a bit more sleep each night, especially on school nights. Also, the players fell asleep more quickly after going to bed than did the non-players and they had fewer awakenings each night. As a result, the players felt more restored and were in a better mood each morning. This carried on through the day as measures of mood, tiredness and concentration during waking hours were all better.

Overall, the soccer players had more favorable sleep patterns and increased daily performance than their non-playing classmates. The researchers suggest that vigorous, regular exercise may be the key. This form of activity may lead to some long-term metabolic alterations that are crucial for regulating sleep. For example, earlier studies have shown a link between exercise training and a number of hormonal fluctuations that influence factors like hunger and tiredness. The investigators also point out that competitive sports may simply encourage adolescents to adhere to a fixed schedule and a more structured sleep routine. Because of the time commitment required by soccer practice and the knowledge that rest is an important part of training, players may stick to a regular bed and wake-up times. In either case, the advantages are clear. Playing competitive soccer improves sleep quality which, positively affects daily mood and concentration.

Reference:

Brand S, Beck J, Gerber M, Hatzinger M, Holsboer-Trachsler E (2009) ‘Football is good for your sleep’ Favorable sleep patterns and psychological functioning of adolescent male intense football players compared to controls. Journal of Health Psychology, 14:1144-1155.
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Digital Success: Finger Length and Athletic Prowess

Talent identification in youth sports is often more of an art than a science. Researchers and coaches continually debate what markers indicate natural talent for a particular sport. Factors such as genetics and anatomy are thought to determine potential ability. A newly published research review now argues that something as simple as finger lengths may predict athletic prowess. As it turns out, the relative lengths of the index and ring finger may be a marker of natural ability. Individuals with longer ring fingers may be more gifted athletes.

The relationship between the ring finger and index finger length is called the 2D:4D ratio. The 2D:4D ratio is calculated by dividing the length of the index finger (2nd digit) by the length of the ring finger (4th digit). Researchers often measure the palm side, taking the distance from the crease nearest to the palm to the tip of the finger (see Figure 1). For most, this ratio is 1.0 (they are the same length). However, this ratio can range from about 1.05 (longer index finger) to 0.85 (longer ring finger).

Researchers form England and Germany performed a meta-analysis of more than 20 studies that focused on the link between 2D:4D ratio and various sports and performances. For the most part, research shows that individuals with smaller the ratios tend to have greater athletic prowess. That is, those with longer ring fingers are more often the better athletes. The relationship seems to be stronger for endurance athletes and weaker for sprint, power and strength athletes. For example, the 2D:4D correlates better with 10k race performance than with 50m sprint time.

Three of the studies reviewed focused on the abilities of soccer players. Two studies showed that English professional players competing at the highest levels have lower 2D:4D ratio than lower division players and non-athletes (see Figure 2). Another study reported this ratio was linked to talent rated by the players and by others. Thus, there seems to be some relationship between the 2D:4D ratio and soccer ability.

The reasons for these relationships are not completely clear. Many feel that the 2D:4D ratio is a marker of pre-natal testosterone. That is, how much testosterone the fetus is exposed to in the womb may affect the finger length ratio. It may also influence a number of physical characteristics such as cardiovascular capacity. So, there may actually be a biological explanation for the relationship between the 2D:4D ratio and athletic prowess.

However, before coaches put the measuring tape to their players’ hands, there are some important considerations. While researchers have shown a correlation between finger length and physical performance, the relationship is not overly strong. On average, the 2D:4D ratio accounts for around 6% of the variation in athletic prowess. In soccer, it’s probably even less. Also, the ability to predict success using this ratio is debatable. In an interview article, a prominent researcher suggests that while 2D:4D ratio may be useful to identify natural talent, especially in sports that rely on endurance, there are some limitations. He is quick to point out that the finger ratio is a “probabilistic” indicator and that there are many other factors that determining success. Simply having a relatively long ring finger doesn’t necessarily guarantee either talent or success. Many, many other factors play very important roles in the development of these characteristics.

Hönekopp J, Schuster M (2010) A meta-analysis on 2D:4D and athletic prowess: Substantial relationships but neither hand out predicts the other. Personality and Individual Differences, 48:4-10.

Manning JT, Taylor RP (2001) Second and fourth digit ratio and male ability in sport: implications for sexual selection in humans.Evolution and Human Behavior, 22:61-69.
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ACL Injury Prevention – The Evidence Mounts

Unfortunately, knee injuries are all to commonplace in the sport of soccer. In particular girls suffer anterior cruciate injuries at a rate that is 4-8 times higher than their male counterparts. The reasons for this increased risk are somewhat debatable but most researchers suggest that deficiencies in strength, balance, agility and technique play key roles. Given this, several ACL injury prevention programs have been developed with the goal of correcting these deficits including the FIFA 11+ and the Santa Monica PEP programs, to name a few. A new study from researchers in Uppsala University in Sweden shows that a simple, low-cost warm-up program that incorporates components of awareness, technique and strength reduces the risk of knee injuries in female players by more than 75%.

Researchers enrolled 48 girl’s youth teams in two Swedish counties in the preventative training program (intervention group). Another 49 teams served as the control group. In all, more than 1500 players participated in the study. The players ranged in age from 12 to 19 years. The intervention program began with the start of pre-season training (February) and continued through the end of competition (October). The intervention group performed the HarmonKnee preventative program (LINK) twice per week during the pre-season and once per week during the regular season. This program has three key components, 1) to increase awareness about injury risks, 2) to provide a structured warm-up program and 3) to provide strengthening exercises designed to improve movement and reduce stress on the knee joint. The awareness component consisted of a player-directed seminar on the importance of preventing knee injuries. The training components were similar in nature to programs advocated by other groups such as the FIFA 11+. It consisted of 5 parts: 1) warm-up, 2) muscle activation, 3) balance, 4) strength and 5) core stability (LINK). The emphasis was placed on performing the exercises with good technique rather than on the number of repetitions. The exercises took 20-25 minutes to complete and required no extra equipment of resources.

Over the course of the study, the incidence, type and severity of knee injuries was recorded for each teams and each player. In addition, the number of practices missed due to recovery was noted.

The results are impressive. First, the researchers found that the compliance rate for the intervention was very high with nine of the 48 teams in the intervention group reporting 100% compliance and 36 other reported 75% compliance. Such high compliance rate suggests that coaches and players found the program to be easy to incorporate into the training sessions and enjoyable to perform.

Second, and most important, the intervention resulted in a 77% reduction in the knee injury incidence rate. For non-contact knee injuries, the rate was reduced by 90% and there were no ACL injuries in the intervention group. Also, the injuries that occurred in the intervention group were less severe than those that occurred in the control group.

This study adds to a growing body of research indicating that injury prevention programs can reduce the risk of ACL injury in female players. A review of multiple studies by Korean researchers shows that prevention programs are associated with a 60% reduction in knee injury incidence (LINK). A Norwegian study using the FIFA 11+ program showed a 46% reduction in knee injuries despite a relatively low compliance rate (LINK). As a bonus, the FIFA 11+ has been shown to improve both speed and power.

Based on this information, coaches should be strongly encouraged to include ACL injury prevention as part of their training sessions, especially coaches working with girls. The present study uses a program that is very simple and low-cost, one that requires as little as 20 minutes per session. Using the program as little as twice per week during the pre-season and once per week during the regular season is effective.

Many coaches feel that they already have a limited amount of time to work on the technical and tactical components of the game as well as including some fitness training. Ninety minutes a few times per week can be used up quickly. However, consider that most teams spend at least 10-20 minutes each session warming up. Using an injury prevention program as a warm-up would require only 5-10 additional minutes of practice time. Also, consider the considerable consequences of a single ACL injury. A conservative estimate of the surgical and rehabilitation costs of an ACL rupture is around $17,000. In addition, these patients are at a higher risk of developing osteoarthritis later in life. Add to that the emotional and psychological impact on the individual and the implications for team from losing a key player. When both the personal and financial costs of an ACL injury are weighed against the reduction in injury risk, it is easy to see how a few minutes per week spent on injury prevention is well worth the effort. This seems like a classic case of an ounce or prevention being worth much more than a pound of cure.

Reference:

Kiani A, Hellquist E, Ahlqvist K, Gedeborg R, Michaelsson K, Byberg L (2010) Prevention of soccer-related knee injuries in teenage girls. Archives of Internal Medicine, 170:43-49.
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Artificial Turf: Injuries and Chronic Pain in Youth Players

Over the past few years, there has been a tremendous increase in the use of third-generation artificial turf fields for both training and match play. These surfaces are so popular that in 2001 FIFA established standards for turf fields and have approved them for events such as the U-17 World Cup. The advent of turf field has also prompted a large number of research studies comparing injury risks between artificial and grass fields. For the most part, these studies show that the incidence injuries such as ankle sprains and ACL tears are not increased when training or playing on turf. However, a common complaint of players who spend much of their practice time on turf is chronic pain. A new study out of Japan finds that neither acute injuries nor complaints of chronic pain are increased in youth players who train predominately artificial turf.

Researchers tracked six Japan Football Association affiliated youth teams for one year. Four of the teams trained exclusively or primarily on grass while the other two trained primarily on turf. Players on these teams ranged in age from 12 to 17 years. In all, 301 players participated in the study. Acute injuries and chronic pain complaints were recoded daily by each team’s medical staff. In addition, coaches recorded the amount time each player trained and plated of grass or turf.

The most common acute injuries suffered by the players were ankle sprains and contusions (bruises). Ankle sprains accounted for about half of all injuries. However, there were no differences in the injury rates (the number of injuries per hours of play) between the teams training on turf and grass. This was the case whether the injuries occurred during training or during matches.

Low back pain and knee pain accounted for most of the chronic pain complaints. Again there was no difference in the incidence of total number of complaints between the grass and turf teams. However, there was a small increase in the incidence of low back pain complaints in the teams that trained on turf.

The researchers re-examined their data to better understand why players who train on turf seem to have more chronic back pain. One key issue is the time the teams spent training on turf. The turf teams trained 33% more than the grass teams. They trained about 8.5 hours per week and the grass teams averaged around 6.5 hours. That is, turf teams held the equivalent of one extra session per week. Why this occurred is not known but it is not surprising that this group of players experienced more chronic pain.

Two broad conclusions can be drawn from this study. First, training on the new artificial turf fields does not increase a youth player’s susceptibility to either acute injury or chronic pain. Like most of the previous research into the safety of artificial turf fields, this study suggests that these fields are safe for young players to train on.

Second, coaches should be aware that longer training, especially on turf, can raise the risk of chronic pain in young players. In this study low back pain was associated with time spent on turf. One advantage of artificial turf is that that it can be used throughout the year, regardless of weather. As a result, training sessions are less likely to be cancelled due to poor field conditions. Perhaps these “off days” due to weather actually allow young players to recover. While this study does not suggest that training on turf directly causes low back pain, it does suggest that coaches should monitor players closely in terms of chronic pain. They should be aware of the amount of time their teams train, especially on artificial turf.

Reference:

Aoki H, Kohno T, Fujiya H, Kato H, Yatabe K, Morikawa T, Seki J (2010) Incidence of injury among adolescent soccer players: A comparative study of artificial and natural grass turfs. Clinical Journal of Sports Medicine, 20: 1-7.
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Self-Reflection: A Possible Key to Elite Performance

There is little doubt that an athlete’s attitude towards practice affects how much is learned and how much improvement is made. Focus, effort, and attention are all important to leaning and developing the skills needed to compete at a high level. In a new study focusing on Dutch youth players, researchers found that the ability of players to reflect on and critically evaluate their own performance may be an important developmental aspect. Their findings show that elite youth players often use the process of self-reflection. They are more aware of weaknesses in their game and use this information to invest more effort into practice than their less talented peers.

The researchers examined a concept called self-regulation. Self-regulation is the ability to control ones thoughts, feelings and actions. This usually refers to an individual’s capacity to respond and adapt to their social or physical surroundings. For an athlete, self-direction is often thought of in terms of performance on the field - focus, attitude and decision making during a match. However, self-direction can also be applied to player development. In this case, the athlete uses self-regulation to identify and correct weaknesses and to focus on achieving those goals. In short, a self-directed player has the psychological characteristics to understand what they need to do to improve performance as well as the motivation to make those changes.

In this study, youth players (U13-U17) affiliated with Dutch professional clubs (elite) and regional clubs (sub-elite) were enrolled. All of the elite players played in the highest national leagues and while most of the sub-elite players played in regional and local leagues. All of the players were administered a questionnaire designed to assess various aspects of self-regulation such as planning, evaluation, reflection, effort and confidence.

The results of the questionnaires showed that the elite players excelled in two key areas of self-regulation: reflection and effort. The elite players more often reflected on their training and competitive performances. This allowed them to identify weaknesses in their game and to develop strategies for improvement. The elite players were also more motivated to put in the time and effort needed to correct their shortcomings. The researchers argued that these personality traits translate into a more effective developmental environment. By understanding their weaknesses and being driven to improve, the elite players get more out of competition and training sessions than do the sub-elite players. In a nutshell, the elite players know what to work on in training and are motivated to improve. This is a concept called deliberate practice – training that is directed towards specific outcomes.

What does this mean for the coach and player? Coaches often talk with players and point out weaknesses and shortcomings in the players abilities. In many cases, information flows in one direction, from the coach to the player. The authors of this study suggest that this pathway be reversed. Instead of simply telling players what they need to work on, encourage them to reflect on their performance and critically evaluate what aspects of their game need improvement. Have them think about what they did well and more, importantly, what they did poorly. Once players can describe where their weaknesses lie, help them identify ways to improve and develop a more deliberate practice session. By using this approach, players will be more motivated because they understand why certain drills are being used and will “buy into” what the coach is trying to accomplish. The goal is to have players use reflection on past performances to put more effort onto executing skills more successfully.

Using a self-directed approach to training that includes self-reflection will make it possible for players to develop their skills more effectively. This in turn will lead to faster development, greater skill development and improved performance on the pitch.

Reference:

Toering TT, Elferink-Gemser MT, Jordet G, Visscher C (2009) Self-regulation and performance on elite and non-elite youth soccer players. Journal of Sports Sciences, DOI:10.1080/02640410903369919
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Trade-offs Between Speed, Shot Velocity and Accuracy

Successful goals typically come from shots that have both pace and accuracy. How players approach the ball when taking a shot can affect both of these parameters. Rushing a kick can result in a shot that is both slow and less accurate. Slowing the approach can improve accuracy but reduce shot velocity. To better understand these relationships, researchers at the University of Aarhus in Denmark looked at the trade-offs between approach speed, shot velocity and accuracy. They found that players generally self-select the optimal approach speed for both shot velocity and accuracy. The implications are that forcing players to alter their approach speed, defenders may be able to adversely affect the attacker’s shot and reduce the chances of conceding a goal.

The study enrolled a group of trained players from the Danish professional leagues (20-30 years of age). They were asked to take a series of shots on goal. The first set of shots was for speed. Players were told to take their normal approach and kick for maximal ball speed. They were then asked to repeat using various approach velocities ranging from standing still to 150% of their normal approach speed. The second set of shots was for accuracy. Here they were asked to hit a target positioned just above field level. The idea was to simulate a penalty kick placed in the side of the goal with enough pace to prevent a goal keeper from blocking the shot.

For all of the shots, both the player’s approach velocity and shot speed were recorded.

All of the players self-selected an approach speed that maximized their shot velocity. That is, when they approached the ball faster or slower than normal, their shot velocity decreased. This approach speed was between 52-77% of their peak running velocity. When players increased their approach speed by 50%, their shot velocity fell by as much as one-third. Slower approach speeds also slowed shot velocity by up to one-quarter.

One of the more interesting findings was that approaching the ball at near maximal running speed resulted in shots that were actually slower than those taken without an approach (standing still).

When a target was used and accuracy was required, peak shot velocity dropped by ~15%.

The results indicated a couple of things. First, players generally self-select the approach velocity that gives them the greatest shot speed. Increasing or decreasing the approach run results in slower shots.

How does this study fit into game situations? Here the authors raise an interesting scenario. They point out that there are situations where a defender is chasing an attacking player who posses the ball. The defender has to make a decision – make a take and risk not winning the ball or continue running with the attacker and risk giving up a shot. They suggest that the better option is to force the attacker to run at a high speed, increasing his or her approach speed when the shot is taken. This should then result in a shot that has a lower velocity and less accuracy.

This study may also have implications for training attackers. Often players train by taking shots at a self-selected approach speed, one that maximizes shot velocity. During game situations, slower and less accurate shots probably result from approaches that are outside of the players “comfort zone” for approaching the ball. Perhaps it is possible that training with varying approach speeds might expand this comfort zone. Players may then be able to better maintain near maximal shot velocities during match situations. An interesting concept, but one that needs a bit more research…

Reference:

Andersen TB, Dorge HC, (2009) The influence of speed of approach and accuracy constraint on the maximal speed of the ball in soccer kicking. Scandinavian Journal of Medicine and Science in Sports. DOI: 10.1111/j.1600-0838.2009.01024.x
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Soccer as Preventative Medicine: More Evidence

There is little doubt that playing soccer directly affects one’s heath. The amount of physical activity and the emphasis on proper diet found in competitive soccer clearly reduces the risk and incidence of health-related problems such as childhood obesity. It also seems that the benefits of youth sports carry over to adulthood. Now, more evidence has emerged linking competitive athletics with decreased risk of health problems later in life. Researchers in Turku, Finland have found that participation in competitive sports is associated with reduced odds of developing metabolic syndrome.

Metabolic syndrome is cluster of several risk factors that increase ones odds of developing Type 2 diabetes, heart disease and stroke. These include obesity, elevated blood pressure (hypertension), elevated blood glucose, insulin resistance and elevated cholesterol. Some studies suggest that 25% of the US adult population may suffer from metabolic syndrome. More recent studies indicate that some of these risk factors are beginning to appear in both adolescents and children. Researchers agree that one key strategy to preventing or reversing metabolic syndrome is exercise, physical activity and diet.

In this study, researchers examined a series of surveys administered to Finnish children and youth (ages 6-18). The Young Finns Study asked a wide range of questions regarding health, physical activity, diet, etc. Specifically, the initial survey conducted between 1962 and 1977, asked the kids if they played competitive sports with a sports club less than once per week (non-athletic level), once per week (moderate-athletic level) or more than once per week with regional or national team play (high-athletic level). Because the survey was administered over the course of several years, the investigators could determine which athletes dropped out (played less 3 years) and those who persisted playing three or more years.

The original survey participants were contacted again after they had reached 24-39 years of age. At that time, they were asked about their current health status including several markers of metabolic syndrome (body weight, blood glucose, etc.).

The results showed that 16% of the male non-athletic group had developed metabolic syndrome compared to only 6% of the high-athletic group. In females, the rates of developing metabolic syndrome were lower, but the difference between non-athletic and high-athletic groups was similar to the males. In fact, the odds of non-athletic group developing metabolic syndrome were 3-4 times that of the high-athletic group.

Persistent athletes had lower odds of developing metabolic syndrome than those who played less than three years (drop outs). High-athletic athletes also had lower risk than moderate-athletes. Lastly, being a starter did not affect the risk as long as participation persisted.

This study indicates that participation in competitive youth sports for three or more years is associated with reduced risk of developing metabolic syndrome. Persistence seems to be the key rather than the individual skill level.

There are two reasons why this might occur. First, it is possible that competitive sports may lay the foundation for a healthy lifestyle. Regular exercise and proper diet, both of which lower the risk for metabolic syndrome, may be instilled at a young age. In a study reported earlier on the Science of Soccer Online, researchers found that kids who played sports at an early age remained more physically active later in life (link). So there is reason to suggest that competitive youth sports do in fact develop habits that will keep individuals health through adulthood.

Second, it is also possible that genetic factors and what is called self-selection may be at play. Genetics influences a number of metabolic syndrome characteristics such as blood pressure and cholesterol. It may be that kids who have a genetic make-up that makes them less susceptible to developing these risk factors are the same ones who gravitate towards competitive sports. That is, athletes may not only be gifted in terms of sports performance but also in terms of avoiding metabolic syndrome risk factors.

In either case, this finding has implications for promoting youth sports as part of a healthy lifestyle. It is yet another piece of a growing body of evidence linking youth sports to a healthy adult lifestyle. Soccer clubs can play an important role by providing an avenue for participation in physical activity and by instilling habits that will last a lifetime. These include, engaging in regular vigorous exercise and eating a diet that is high in nutrients and low in fat.

Reference:

Yang X, TElam R, Hirvensalo, Viikari SJA, Raitakari (2009) Sustained participation in youth sport decreases metabolic syndrome in adulthood. International Journal of Obesity, DOI: 10.1038/ijo.2009.171.
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Does ACL Injury Prevention Really Work?

One of the major problems facing female athletes is the risk of tearing their anterior cruciate ligament. Non-contact ALC injuries occur in women at a rate 4-6 times that of males. In addition to the personal costs, the financial costs of surgery and rehabilitation have been conservatively estimated at $1.7 billion annually. The exact reasons why women are so much more susceptible to ACL injuries than are men are still being debated. However, one issue that is clear is that something needs to be done to lower the risk of injury. One solution is the development of various neuromuscular training programs designed to prevent ACL injuries. In general, these programs use strengthening, plyometric, flexibility and balance exercises to enhance knee stability. But, do they really work? Do they actually reduce the risk of injuries in women?

A group of Korean researchers recently addressed these questions. To do this, they examined all of the available research studies involving women, ACL injuries and ACL injury prevention programs. Using these studies, this they performed a meta-analysis of the results. A meta-analysis is a statistical tool whereby the results of many studies are “pooled” and analyzed simultaneously. The goal is to come up with a “consensus” result. This process provides a more comprehensive look at whether or not these programs are effective in lowering the incidence of ACL injury.

Seven key studies were analyzed. All were similar in that they used young female subjects. Some subjects were under the age of 18 while a few studies used college-aged girls. In all, more than 11,000 subjects were included in the seven studies. The seven studies also used what is termed a “randomized control trial”. This means that each study compared a treatment group (received ACL injury prevention training) to a control group (received no prevention training). Also, the subjects were randomly assigned to one of the two groups.

The researchers found that the use of neuromuscular training was very effective in preventing ACL injuries in female athletes. The meta-analysis revealed that the neuromuscular training programs reduced the odds of suffering an ACL injury by 60%. These programs were more effective in young athletes. In adolescents, the odds of injury were cut by 73%.

The researchers also found that using a neuromuscular training both before and during the season was more effective than using the program only during pre- or in-season. The intensity of the program seemed to be an important factor. Programs conducted at practice and supervised by a coach were more effective than a home-based program. Lastly, plyometrics and strength training seems to be a bit more important than balance training. It seems that starting early in a players career may be more effective that beginning later.

Back to the original question; does ACL injury prevention really work? Based on this paper, the answer is a definitive yes. By including neuromuscular training as a part of both pre-season and in-season practice, the risk of suffering an ACL injury can be substantially reduced.

It is important to point out that this study shows that training can reduce the risk of injury. It does not indicate that this type of training will prevent injuries from occurring. Some injuries will occur despite the best training efforts. However, lowing risk will reduce the overall number of injuries that occur on a single team or within an individual club. Thus, improving the odds of avoiding ACL injuries will help a large number of players stay healthy and increase the chances of a successful season.

Reference:

Yoo JH, Lim BO, Ha M, Lee SW, Oh SJ, Lee YS, Kim JG (2009) A meta-analysis of the effect of neuromuscular training on the prevention of the anterior cruciate ligament injury in female athletes. Knee Surgery, Sports Traumatology and Arthroscopy, DOI: 10.1007/s00167-009-0901-2.

For more info on neuromuscular training programs, follow these links:

FIFA 11+

Santa Monica Orthopedic and Sports Medicine Group PEP Program
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Menthol: Fresh Breath and Better Performance?

Exercising in the heat is always a difficult task. Hot environments place a tremendous demand on the cardiovascular and thermoregulatory systems. This typically leads to decreased performance, particularly in sports that last an hour or more. As a result, coaches and players are always searching for new ways to perform in the heat. In a new study, researchers at Manchester Metropolitan University in the United Kingdom report that simply rinsing the mouth with menthol, a common flavoring agent, can actually improve performance during exercise in a hot environment.

The researchers asked nine moderately trained subjects to exercise on a stationary bicycle at ~65% of their maximal capacity. They were told to continue exercising as long as possible while the total duration was recorded. On one occasion, subjects swilled a 0.01% menthol solution in their mouth for 10 seconds after which it was spit out without swallowing. On the other occasion, they swilled an orange flavored placebo drink. They were given the solution every 10 minutes and were allowed to drink as much water as they wanted. All of the bouts were performed in the heat at a room temperature of 34°C or 93°F.

Eight of the nine subjects improved their exercise duration when they swilled the menthol. Total exercise time increased from an average of 58 to 63 minutes. Despite this improvement in performance, there were no differences in the subjects’ body temperature or the amount of energy expended. What seemed to be improved was the perception of their effort. Overall, the subjects felt that that the menthol was “refreshing” and “stimulating”. This resulted in the subjects feeling a reduced sense of effort during the exercise bout, particularly a reduced effort of breathing. That is, breathing felt easier which made the exercise seem easier.

The authors conclude that the improvement in performance was probably due to psychological factors. The menthol may have stimulated some region of the mouth which activated a network of taste- and reward-regions of the brain. The pleasantness of a cool mouth coupled with taste and flavor may have caused the subjects to experience less discomfort as they were approaching exhaustion.

Menthol is an interesting compound. It comes from various mint oils as well as peppermint. When it is applied to the skin, there is a cooling sensation. The same sensation is experienced when taken orally. As a result, many companies include menthol in all sorts of skin creams, foods, mouthwashes, medications and cigarettes. Ben Gay ointment, peppermint candies, and many throat lozenges all contain menthol. Some people report that this cooling effect increases alertness and reduces minor pain. For example, a throat lozenge soothing sore throat pain. So it is not surprising that swilling a menthol drink might reduce one’s perception of breathing during exercise.

There are a few important points to be made about this study. First, and most importantly, the menthol did not actually lower body temperature. The improvement in performance does not indicate that menthol protects against any of the potential problems of exercising in the heat such as dehydration. It remains very important that when exercising in the heat, players drink plenty of fluids and to be aware of heat-related illness and injury.

Second, the type of exercise performed in this study doesn’t really simulate match play. The subjects were asked to exercise at a constant, pre-determined pace and to continue as long as possible. Match play requires players to start and stop and run at a variety of speeds. This means that the reduced perceived exertion caused by the menthol may be specific to the type of exercise studied and may not occur during an activity like soccer. Also, it is difficult, if not impossible for players to drink every 10 minutes during a match.

Despite these drawbacks, the finding that menthol may improve performance is intriguing. While it may not actually combat the physiological effects of exercising in the heat, including it in drinks may have some positive psychological effect. This study also adds to a growing body of research showing that what goes into your mouth may affect exercise. Earlier, the SSO reported that merely swilling a carbohydrate beverage (sports drink) might also affect the central nervous system and improve performance (LINK). These studies suggest that the mouth may be more important than previously thought. It may be more than a simple a passage way to the stomach but a key sensory component of perceived exertion.

Reference:

Mundel T, Jones DA (2009) The effects of swilling an L(-)-menthol solution during exercise in the heat. European Journal of Applied Physiology, DOI: 10.1007/s00421-009-1180-0
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Kudos to the Soccer Moms

By design soccer is an activity that promotes health and fitness. The amount of exercise performed at practice and the emphasis on proper diet directly affects players’ fitness and promotes a lifestyle that influences health well into adulthood. A recent study now suggests that participation in youth sports may have other, unanticipated effects that may lead to an overall healthy lifestyle. Researchers from SUNY Brockport have found that playing sports may have some influence on whether or not high school kids use their seatbelts.

The study analyzed the data found in the US National Youth Risk Behavior Survey. This survey is administered every two years to groups of 9th through 12th graders. For this study, two aspects of the survey were used. The first was a question about seatbelt use when riding in a car. The teenagers were categorized as those who always / mostly / sometimes used seatbelts and those who rarely / never used them. Second, athletic participation was determined by how many high school or club sports each kid participated in. Non-athletes did not participate in any sports, moderately involved athletes played on 1-2 teams per year and highly involved athletes played on 3 on three or more teams.

Of nearly 19,000 students surveyed, 81% reported that they used seatbelts at least some of the time. The results also showed that girls were more likely than boys to wear seatbelts as were younger teens versus older teens. The more interesting finding was that both moderately and highly involved athletes reported more seatbelt use than the non-athletes. In this study, non-athletes were 25% more likely to report that they rarely or never wear seatbelts than were the teens that played sports.

The investigators argue that the differences between athletes and non-athletes may be related to personality types and the need for teens to engage in “risky” behaviors. Sports may provide an alternative to risky behaviors such as not wearing a seatbelt. They also suggest that athletes may avoid risky behaviors out of fear that their place on the team may be jeopardized. They may fear being punished by their coach or parents, especially if the behavior results in a violation of seatbelt laws.

While the researchers may be on to something, they may have overlooked a more obvious reason for the increased seatbelt use among teenage athletes. Seatbelt use is a habit that probably gets ingrained early in life. It seems reasonable that young children who grow up wearing seatbelts will use them as teens. This is where the soccer moms step in. How many parents who drive the team carpool have said, “We’re not going anywhere until everyone buckles up”? Could it be that this insistence on seatbelt use helps kids develop a habit that lasts once they’re driving on their own? Maybe all of those trips to and from practice have the unintended benefit of promoting a healthy lifestyle practice!

Nearly everyone is aware of the importance of seatbelt use. Using a seatbelt is estimated to prevent nearly 16,000 deaths annually and as many as 350,000 injuries. Seatbelt use is perhaps the most important factors in preventing injury and death during an auto accident.

So, to all you soccer moms (and dads): keep up the good work. Pestering your kids to wear their seatbelts may be paying off!

Reference

Melnick MJ, Miller KE, Sabo DF, Barnes GM, Farrell MP (2009) Athletic participation and seatbelt omission among US high school students. Health Education and Behavior, in press, DOI 10.1177/1090198107308377.
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FIFA F-MARC "The 11+" Website

The FIFA and the FIFA Medical Assessment and Research Centre (F-MARC) have recently developed a website dedicated to "The 11+". The 11+ is a warm-up program developed for soccer players designed to reduce the risk of lower extremity injuries (for a discussion of The 11+, click here). The website contains downloads such as posters and instruction cards as well as an collection of videos showing how to perform each exercise. The is an excellent resource for those wanting ot incorperate The 11+ as part of a regular warm-up routine.

Click here to visit their website.

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Where Did All the Freshmen Go?

At some point in their soccer careers, many American youth players dream of playing beyond their high school days and joining a collegiate side. For some this becomes a reality. Each spring those high school seniors sign their National Letter of Intent, solidifying a commitment to a college program. Once the fall arrives, these new freshmen take the field and the next step in their playing carriers. However, in many cases, large numbers of newcomers appearing on college rosters are matched with relatively small numbers of veteran players. In fact, it’s not uncommon for programs to have only a handful of graduating seniors. The discrepancy between freshman and senior classes begs the question, “Where did all the freshmen go?”

To gain some insight into this question, the rosters of the nine ACC men’s soccer programs were analyzed. This conference was chosen because it is arguably the strongest college conference in the US. Nearly all of the ACC programs have appeared in at least one College Cup (the NCAA Final Four) and six of the nine programs have won national championships. The analysis focused on the rosters from 2004 to 2009 seasons. The numbers of players in each class were tallied as was the number of years each player appeared on their program’s roster. Players were classified as first year (freshman), second year (sophomore), third year (junior), fourth year (senior) or fifth year. Red shirt players were classified with their original class. That is, a red shirt junior was classified as a senior. Red shirt seniors were classified as fifth year players.

For all rosters combined, the number of players in each class decreased as they aged. As expected, freshmen occupied the largest percentage of players, 30%. Sophomores accounted for 26%, juniors 23% and seniors 21%. Fifth year players accounted for les than 2%.

The main objective of this analysis was to track the ’04, ’05 and ’06 freshman classes over their four years of eligibility to determine how many played for a full four years. These groups of players should appear as seniors on the ’07, ’08 and ’09 rosters. The results were interesting. For those three classes of athletes, less than half, 47% were rostered all four years. Nearly 25% of them were rostered for there freshman year only. Overall the average number of years played by these freshmen at their original institution was less than three.

There was quite a bit of variability between individual programs. One program retained 100% of its freshman players for their four years of eligibility. On the other end of the spectrum, two programs had four year retention rates of less than 30%.

As for the seniors on the ’07, ’08 and ’09 rosters, 61% were from each school’s original freshmen class. For a typical roster of 25 players, only 3-4 began their senior season with a full three years of playing experience in their program. The remaining 39% of the seniors on the roster entered the program after their freshman year with less than four years of eligibility. Those “transfer” players averaged slightly less than two years of playing experience with their new team.

What about women’s programs? For the nine ACC schools that play both men’s and women’s soccer, more than 80% of the freshmen play a full four years. Also, 94% of the seniors listed on the rosters began their careers at the same institution.

Does this occur in other levels of collegiate play? A quick check of team rosters from other conferences and some Division III programs suggests that the answer is yes. While the exact percentages vary, it is clear that a large number of players start out as freshman but do not complete their four years of eligibility.

Why does this happen? Unfortunately these numbers don’t really answer the original question, where did the freshmen go? The loss of players from an original freshman class is probably a combination of factors. Some such as Charlie Davies and Patrick Nyarko choose to forgo their remaining years of eligibility and pursue professional careers in the US or Europe. For some, this may happen after their freshman year. Other players may transfer to other programs for both athletic and academic reasons. Still others may suffer career-ending injuries or simply decide to give up playing and focus on their academic pursuits. Whatever the reason, it’s clear that many freshman players either end their careers or move on to other opportunities before they eligibility is exhausted.

The bottom line, there is considerable turnover in the rosters of men’s college programs. For the ACC, more than half of the freshman players leave their program before they exhaust their eligibility and some are replaced by others entering the program after their freshman year. If the results are projected forward, one can expect that a large percentage of high school players who sign a National Letter of Intent will not complete their four years of eligibility at that institution. Some will end their college careers early and others will finish playing with another program.
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