Fitness, For Parents, Nutrition

Macro-Nutrition For Elite Soccer Players – By Andre Orlando and Richard Bucciarelli

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Below is an article written by University of Guelph-Humber Internship Student Andre Orlando (who is presently completing an internship with Soccer Fitness Inc.) and edited by me.  The article discusses “macro” nutrition, or nutrition at the macro (nutrient) level, for soccer players, with an emphasis on pre-, during-, and post- training/game nutrient intake.  Any soccer player, parent, or coach should find this information useful.  Below is the article, including references.  As an aside, I have to advise any person considering making changes to their diet, to first consult with a physician and/or registered dietician.

I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.

Introduction:

Soccer is a unique and complicated sport that requires multiple energy systems dominating throughout the game. The games usually last 90-95 minutes, with a 15 minute break at half time. One would assume that soccer is mostly dominated by aerobic fitness and the aerobic energy system, but it is not. Soccer consists of short bursts of speed and strength followed by a long chase or battle with opponents, all of which are performed by the anaerobic energy system. Other soccer movements include quicker bursts of power to jump up and win a header or (for goalkeepers) to the side to make a save and in these movements the anaerobic ATP-CP system dominates. All of these different movements occur in several combinations lasting 90+ minutes, so they can also take a toll on the body’s aerobic energy system, which must provide the body with sufficient energy to recover.  With all three of the body’s energy systems working at once, how does one prepare for optimal performance during a game, and for optimal recovery afterwards?  An elite soccer player cannot just eat like a sprinter, or a marathon runner, or even a hockey player because the energy requirements for a soccer player can be much more diverse. A balanced diet focusing on all the essential macronutrients is very important for soccer player’s performance and recovery after a game.

Pre-game or Pre-training nutrition:

On game or training day the player will need to store up optimal energy for optimal performance. If the player eats too little they will fatigue a lot faster and performance will decrease. If a player eats too much they can feel bloated and sluggish and performance will decrease. But if the player has the right meal with at the right time they will perform optimally.

Carbohydrates are a very important macronutrient for soccer players. Once ingested, they are broken down into glucose which is used in glycolysis (anaerobic energy system) or stored as glycogen for later energy use. The recommended amount of carbohydrates for elite soccer players is 200-300g 3-4 hours before exercise or 3-5g CHO/kg of body weight (1). This will provide enough time and carbohydrates to maximize maintenance of blood glucose (1).  Protein is another important macronutrient for soccer a player that forms the building blocks for muscle tissue. The recommended amount of protein is 20-30 grams of lean protein 3-4 hours before exercise (2).  Fat, the third main macronutrient, contains a lot of energy but can cause gastric distress and bloating if consumed close to exercise. It is recommended that the consumption of fat and fiber is low during the pre game or training meal to minimize bloating and gastric distress. Also it is important to note that all pre game meals should be familiar to the athlete, and in general athletes should avoid new or exotic meals before training/playing. Lastly the meal should be accompanied by enough fluid to keep the athlete hydrated and satisfy their thirst, preferably water.

Post-game or Post-training recovery:

It is arguable that post-game nutrition is even more important than pre game nutrition. The post-training/game time period is where all the work done in training and during the game is transferred into actual physical results. The body is broken down during exercise and after exercise it needs to recover and build back up. A primary key to recovery is proper rest and nutrition.  After an intense bout of exercise, muscle glycogen is depleted and needs to be refueled.  This muscle glycogen is what the muscles use to create energy during exercise when there is no immediate access to glucose. To refuel this depleted muscle glycogen carbohydrate ingestion post-exercise are recommended.  It is recommended to consume 1.2 grams per kilogram of body weight of carbohydrates to optimally replenish glycogen storages post exercise (3).  Protein is also key post exercise to optimize muscle protein synthesis. During strenuous exercise muscle tissue is damaged and needs to be repaired. Protein holds the building blocks (amino acids) for this repair of muscle tissue. To optimize muscle protein synthesis it is recommended to intake 20 grams of protein post exercise in three hour intervals up to 24 hours post exercise or until daily protein requirements are reached (4).  Fat intake is not crucial post exercise as long as the daily recommendations are met. It is very important to rehydrate the athlete and make sure they consume enough water so that they do not feel thirsty.

 

Daily Macronutrient Requirements for Soccer players

Throughout the day an elite soccer player should have multiple smaller meals, rather than three big meals. These meals should include fruits and vegetables and meet the full requirements of a soccer player’s daily recommended macronutrient intake. The daily recommended carbohydrate intake for elite soccer players on none training days is 5-7 grams per kg of body weight (5). On training and game days 7-10 grams per kg of body weight of carbohydrates is needed to provide optimal energy and maintain or replenish blood glucose and muscle glycogen storages (5).  Recommended daily protein intake for soccer players is 1.4 grams per kg per day (6). This will allow for optimal muscle protein synthesis and reduce the risk of muscle break down.  Fat consumption is very important for a soccer player as well, because it is required to transport and store fat soluble vitamins throughout the body.  Fat is also a high energy source used by endurance athletes. Fat oxidation provides more energy than any other substrate, and fat is also used for long term energy production (aerobic energy system). The recommended amount of fat is 20-25% of your daily caloric intake (7). Preferably, athletes should consume healthy fats, such as unsaturated omega-3 and 6 fats.  It is also important to note that hydration throughout the day is also very important, and any athlete should be consuming as much water as possible to maintain optimal hydration.

References

1. Potgieter, S. (2013). Sport nutrition: A review of the latest guidelines for exercise and sport nutrition from the American College of Sport Nutrition, the International Olympic Committee and the International Society for Sports Nutrition.South African Journal of Clinical Nutrition, 26(1), 6-16.

2. Boisseau, N., Vermorel, M., Rance, M., Duché, P., & Patureau-Mirand, P. (2007). Protein requirements in male adolescent soccer players.European journal of applied physiology, 100(1), 27-33.

3. Van Loon, L. J., Saris, W. H., Kruijshoop, M., & Wagenmakers, A. J. (2000). Maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid or protein hydrolysate mixtures.The American journal of clinical nutrition, 72(1), 106-111.

4. Moore, D. R., Areta, J., Coffey, V. G., Stellingwerff, T., Phillips, S. M., Burke, L. M., . & Hawley, J. A. (2012). Daytime pattern of post-exercise protein intake affects whole-body protein turnover in resistance-trained males.Nutr Metab (Lond), 9(1), 91.

5. Burke, L. M., Cox, G. R., Cummings, N. K., & Desbrow, B. (2001). Guidelines for daily carbohydrate intake.Sports medicine, 31(4), 267-299.

6. Boisseau, N., Vermorel, M., Rance, M., Duché, P., & Patureau-Mirand, P. (2007). Protein requirements in male adolescent soccer players.European journal of applied physiology, 100(1), 27-33.

7. Burke, L. M., Kiens, B., & Ivy, J. L. (2004). Carbohydrates and fat for training and recovery.Journal of sports sciences, 22(1), 15-30.

Fitness, For Parents, Science

Exercise-Induced Asthma (And How to Deal With It)

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For me, going back to school has had both positive and negative effects on my life.  Among the positive ones has been that it has forced me to do a lot of research and to write articles/papers about various different topics related to sports science.  I recently was asked to write a report on exercise-induced asthma, a condition that is common in athletes, including youth soccer players and many of the individuals that I work with in my business.  Below is the report (plus several relevant references).  Hope you like it and find it useful!

Exercise-induced asthma is a condition in which vigorous physical activity triggers acute airway narrowing in people with heightened airway reactivity (McFadden & Gilbert, 1994).  Narrowing of the airway is commonly called “bronchospasm” as it implies spasm or constriction of the smooth muscle that lines the airway.  This constriction can make breathing difficult or in severe cases, almost impossible.  Exercise-induced asthma can also be caused by an accumulation of mucous within the airway.  In unusual circumstances, exposure to antigens, oxidant air pollutants, or respiratory viruses may increase vulnerability of the airway to the extent that episodes of airway obstruction can follow even minimal exertion (McFadden & Gilbert, 1994).

Individuals suffering from exercised-induced asthma generally report being short of breath, commonly termed “dyspnea” (Powers & Howley, 2014).  Dyspnea is the most obvious and common symptom of exercise-induced asthma.  The most common exercise situation in which dyspnea due to airway constriction occurs is when, following strenuous activity (accompanied with an increase in minute ventilation), exercise continues at a lower intensity and minute ventilation falls, which prompts a re-warming of the airway (National Asthma Education Program, 1991).

The prevalence of exercise-induced symptoms in patients with asthma has been reported to range from 40 to 90 percent (McFadden & Gilbert, 1994, Jones et. al., 1962).  Interestingly, although exercise may be a common (or commonly-occurring) trigger of airway restriction, in many cases exercise may not be the only trigger (McFadden & Gilbert, 1994).  The wide range of incidence of exercise-induced symptoms owes itself to several different factors.  Among them are the intensity of the exercise that elicits a response, which may be much higher in trained versus untrained individuals.  Second, there is a lack of standardization of the exercise tests used to detect a response.  Several different types of exercise tests are used by physicians and respirologists, with different exercise modes (bicycle, running, calisthenics) and intensities being used.  Finally, it can also be very difficult in a laboratory to standardize the environmental variables that control the magnitude of the airway obstruction (McFadden & Gilbert, 1994).

Ventilation and the heat content of inspired air can have a significant effect on the nature of the response and airway restriction in individuals with exercise-induced asthma.  As a general rule, the more strenuous the work, the greater the ventilation required to meet metabolic demands and the more intense the asthma attack.  Some studies have demonstrated that running (high intensity) limits airflow more than jogging (moderate intensity), which in turn limits airflow more than walking (low intensity) (Strauss et. al., 1978, Deal et. al., 1979).  Temperature and humidity of the inspired air is also an exacerbating factor or airway restriction.  Airway obstruction is maximized when the inspired air (and thus the temperature) is cold or dry and minimized when the air is warm and humid (Strauss et. al., 1977).

Some preventative steps can be undertaken to reduce the incidence as well as the severity of exercise-induced asthma “attacks.”  First, a long a properly conducted warm-up will help to gradually warm and raise the temperature of inspired air.  Studies have demonstrated that, when bouts of exercise are performed repeatedly within a period of 40 minutes or less, the bronchial narrowing progressively decreases. A person can thus limit the obstructive consequences of vigorous activity by first undertaking a short warm-up period (Weiler-Ravell & Godfrey, 1981).  Unfortunately, this limitation in the obstruction of the airway following progressive warm-up is only effective against the exercise stimulus (increase in ventilation / cold air) and is not effective against other irritants in the air that may also cause airway constriction (Weiler-Ravell & Godfey, 1981).

A second preventative step to attenuate and eliminate the effects of exercise-induced asthma is the use of medication.  Aerosols of β 2 -adrenergic-agonist drugs, cromolyn, and nedocromil used 10 to 15 minutes before exertion, as needed, are the most common therapies (Tullett et. al., 1985, Roberts et. al., 1985).     Both of these medications have anti-inflammatory effects.  They act by blockading chloride channels and the modulation of mast cell mediator release and eosinophil recruitment, effects which limit the inflammation and irritation that causes the airways to constrict (www.meded.ucsd.edu).    Typically, 1-2 inhalations of β 2 -adrenergic-agonists can attenuate the symptoms of exercise-induced asthma for up to 12 hours, which is more than enough time to allow individuals to complete their desired exercise session (www.meded.ucsd.edu).  Of course, individuals suffering from exercise-induced asthma can never be “cured” in the sense that the condition will always be present.  The symptoms of the disease, however, can be controlled through a combination of proper warm-up and administration of anti-inflammatory medication.

References:

Deal, E.C., McFadden, E.R., Ingram, R.H., Strauss, R.H., Jaeger, J.J. (1979).  Role of respiratory heat exchange in production of exercise-induced asthma. Journal of Applied Physiology, 46:467-475.

Jones, R.S., Buston, M.H., Wharton, M.J. (1962).  The effect of exercise on ventilatory function in the child with asthma. British Journal of Disorders of the Chest, 56:78-86.

McFadden, E.R., Gilbert, I.A.  (1994). Exercise induced asthma.  The New England Journal of Medicine, 330.19: 1362-1367.

Roberts, J.A., Thomson, N.C. (1985).  Attenuation of exercise-induced asthma by pretreatment with nedocromil sodium and minocromil. Clinical Allergy, 15: 377-381.

Strauss, R.H., McFadden, E.R., Ingram, R.H., Deal, E.C., Jaeger, J.J. (1978).  Influence of heat and humidity on the airway obstruction induced by exercise in asthma. Journal of Clinical Investigation, 61:433-440.

Strauss, R.H., McFadden, E.R., Ingram, R.H., Jaeger, J.J. Enhancement of exercise-induced asthma by cold air. New England Journal of Medicine, 297:743-747.

Tullett, W.M., Tan, K.M., Wall, R.T., Patel, K.R. (1985). Dose-response effect of sodium cromoglycate pressurized aerosol in exercise induced asthma. Thorax, 40: 41-44.

Unknown (2015).  Pharmacologic management of asthma.  Retrieved from: https://meded.ucsd.edu/isp/1998/asthma/html/medguide.html.

Weiler-Ravell, D., Godfrey, S. (1981). Do exercise-and antigen-induced asthma utilize the same pathways? Antigen provocation in patients rendered refractory to exercise-induced asthma. Journal of Allergy and Clinical Immunology, 67:391-397.

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The Natural Goalscorer?

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Here is an excellent article written by Paul Cammarata from The Coaching Journey. It discusses the question of whether or not “talent” is innate/natural, or the product of several controllable factors including practice time and effort. Many examples of athletes from different sports are used, including soccer’s Leonel Messi.
I’d love to hear your thoughts about this topic. Drop me a line here to get the conversation started.

The Coaching Journey

Are geniuses born or created? What about natural goalscorers? We’ve all seen a player who just has that knack. Inzaghi was just given the gift of always being in the right place to score. Messi has god-given talent. Beckham always had that knack for hitting the top corner from a free kick. Let’s look at other sports. Ray Allen had a god-given jump shot. Michael Jordan and Kobe Bryant were born clutch. Tom Brady is a natural winner.

It’s my belief that the thought process mentioned above is a seriously flawed notion that many people may hold. And understand, what I’m going to say below goes against many of the nice quotes you’ll read from most top athletes who describe their abilities. This article will inevitably ruffle some feathers because many who hold the traditional view of “natural talent” can’t conceive of the fact that another Messi can be developed…

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Fitness, Injuries, Science

Head Injuries in Soccer

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In my present Advanced Exercise Physiology class, we were asked to write a small article discussing head injuries in our sport of choice.  For me, of course, there was no choice of which sport to write about!  Below is my report.  Of note in this report is that the commonly recommended “secondary prevention” method of dealing with head injuries and concussions in sports (including in soccer) is the use of baseline and follow up cognitive testing.  I am presently in the process of arranging for this service to be offered at the Soccer Fitness Training Centre – stay tuned and enjoy the article!

Soccer is a unique sport, in that the unprotected head is used both to control and advance the ball during game play.  Not surprisingly, injuries to the head can be common in soccer, and can include contusions, fractures, eye injuries, and concussions (Kirkendall et. al., 2001).  A recent review by Al-Kashmiri & Delaney (2006) examined several different studies utilizing statistical analysis of head injuries in soccer.  Among their reported findings were:

  • Head injuries comprise 4-22% of total injuries in soccer (Powell & Barber-Foss, 1999)
  • Rates of skull fracture or internal head injury are roughly 1-2 injuries per 10,000 soccer players per year in the United States (Delaney, 2001)
  • Concussion rates among university soccer players in the United States have been reported to be 0.6 concussions/1000-athlete exposure (men) and 0.4 concussions/1000-athlete exposure (women); unfortunately, there is also widespread belief that, because many concussions or head injuries are mild and thus not sufficient enough to warrant emergency room visits, these reported numbers of concussion occurrence are greatly underestimating the true numbers of concussions among athlete populations (Boden et. al., 1998)

Prevention of head injuries in soccer has been recommended to be approached using two strategies: primary prevention, and secondary prevention (Kirkendall et. al., 2001).  Primary prevention generally comprises strategies used to prevent a head injury from occurring at all, and can include advocacy for rule changes, equipment design, supervision and proper fitting of helmets, and training/conditioning exercises.  An example of primary prevention in soccer would be the use of helmets like the “Full90” headgear created in 2005 for soccer and other field sports.  The Full90 helmets have been proven to significantly reduce the forces generated both when heading the ball, and in other head contact injuries in soccer (www.full90.com).

Secondary prevention, on the other hand, typically involves management of head injuries after they have occurred.  In soccer and several other sports, concussion testing such as the “ImPACT” or “Immediate Post-Concussion Assessment and Cognitive Testing” have been used by physicians, athletic therapists, and other health and fitness practitioners.     Currently, more than 10,000 medical professionals have been trained by ImPACT on concussion management and the ImPACT Program, and it is also in use by the majority of teams in many professional sports leagues including Major League Soccer (MLS).  The value of baseline and follow-up tests like the ImPACT test is that they serve to specifically define an athlete’s cognitive abilities, with a standardized set of rules and criteria used to determine the nature, severity, and return-to-play guidelines for athlete’s head injuries.

Of course, participation in any contact sport (including soccer), carries risks of being injured, among them risks of head injuries.  Having a good system and plan including both primary and secondary prevention strategies can help to both minimize the incidence of occurrence and risks of head injuries, and also to properly manage and treat these injuries if and when they do occur.

Fitness, Science

The Science Behind Cool-Downs

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These days, most coaches and players seem to have recognized the importance and need for a “cool-down” – some form of light or low intensity cardiovascular exercise – at the end of a training session or game.  Many of the coaches and even some of the younger athletes I work with are able to explain in “layman’s terms”, some reasons why cool-downs are important.  If/when I ask, I frequently hear responses such as “it gets your heart rate back to normal” or “it brings your body temperature back down.”  Because this is a topic that has always been of interest to me, I thought I would look into it a little bit more by searching for an answer to the following questions:

  1. Is there any empirical evidence to support cooling-down following intense exercise?
  2. What type of cool-down will work best for soccer?

Among the benefits of cool-downs are, as stated earlier, a slow and gradual return of both heart rate, and body temperature, back to resting levels.  Removal of lactic acid, which is a painful and toxic by-product of intense exercise including soccer, is also a critical benefit of cooling-down.  Several studies (Brooks, 1985, Brooks 1986) have demonstrated that lactic acid is oxidized (a process by which it is removed from muscles and broken down into non-toxic pyruvic acid) following exercise, rather than during exercise.  Furthermore, recent research has also shown that the removal of lactic acid from the blood (determined by measuring the blood concentration level) is enhanced by up to 25% when light exercise (about 35% of VO2Max) is performed following intense exercise, rather than when no exercise is performed (Dodd et. al., 1984).  From this information, it can be surmised that performing a cool-down following soccer is a useful way to help remove some of the lactic acid that builds up during training and match play.

But what is the best intensity at which to perform a cool-down?  A recent study set the intensity of the cool-down at a percentage of the lactate threshold (“LT” – the exercise intensity at which lactic acid accumulation begins to rise), rather than a percentage of VO2Max. They found that when subjects did their cool-down at intensities just below the lactate threshold (90-95% of the LT), blood lactic acid was removed faster than at lower (40% to 60% of the LT) intensities (Menzies et. al., 2010).  This particular study was done using trained distance runners (not soccer players) however, because soccer players do run fairly large distances during games (up to 15 kilometres) and at relatively high intensities (70-80% of VO2Max), these findings are applicable to soccer.

Based on the research I examined, it seems as though soccer players will benefit more from cool-downs that are of a moderate/high intensity (90% of the lactate threshold) rather than of a lower intensity.  The cool-down protocols in the studies I found used either running or cycling on a stationary bicycle for 10-15 minutes at the prescribed intensities.  Because soccer is played on a field, running is the better choice for cooling-down, as it can be performed immediately following the completion of a training session or game.   Hopefully this article has helped to shed some light on the science behind cool-downs, and provided coaches and players with some useful information to help them maximize their post-training/game recovery.

I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.

Matches

Rene Higuita – “The Boss” – video from “Keep it on the Deck”

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It’s March Break, which means all the youth soccer players across the country have a week off of school, and many of them also have reduced soccer schedules.  For me, March Break has resulted in my first free Saturday since Christmas!  As a result, I thought I would post a video which has nothing to do with Soccer Fitness, but instead has only a very high entertainment value.

Below is a link to an awesome highlight video posted by ‘Keep it on the Deck’s’ Facebook page, of Colombian goalkeeper Rene Higuita, who played professionally in South America and with the Colombian National Team in the mid-late 1980’s and early 1990’s.  He was known as “El Loco”, and if you watch the video, it’s not hard to see why.  He would frequently go on long dribbling runs outside of his box, narrowly avoiding tackles and sometimes making it all the way into the opponent’s penalty area before either being brought down or simply getting tired.  As if these actions weren’t risky enough, Higuita also toyed with opposing forwards, tempting them with fakes and feints and dribbling around their tackles, and even used his trademark “scorpion kick” (where he would jump forwards and kick both of his legs high up behind his head to stop shots on goal.  This behaviour must have driven his coaches mad, as was the case when he lost the ball to Cameroon’s Roger Milla (who went on to score the winning goal) in Colombia’s Round of 16 loss to Cameroon at the 1990 World Cup.  But, as you will also see from the video, Higuita was such an exceptionally talented athlete and goalkeeper, who could stop shots and breakaways, start attacks and counter attacks, and even take and score some incredible free kicks, that he seemed to make up and atone for his crazy plays.  I remember reading an article about him as a kid that described how he told his coaches “I am who I am, you either accept me or do not play me.  But I will not change.”

I hope you enjoy the video (and the rest of the March Break).  I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.

Fitness, Science

’45 Types of Fit People’ Re-Post from www.broscience.com

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The website http://www.brosscience.com recently posted a very interesting series of pictures of 45 elite level athletes from a variety of sports (including soccer), wearing nothing but their underwear!

The different types of sports bodies on display, ranging from thin with extremely low body fat and muscle mass (marathon) to heavy set with huge muscle mass and relatively high body fat (weightlifting) are fascinating to see.  Among the athletes pictured are World Champions and Olympic medallists, as well as elite professional athletes from a variety of different team and individual sports.  What is most unique and impressive about these pictures is that they clearly prove that there is no such thing as having a “fit” body; the most important factor for any athlete (including soccer players) is that their bodies are able to perform optimally.

Below is a link to the post.  I really enjoyed it and I think you will as well.  I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.

http://broscience.co/45-types-of-fit-people-how-world-class-athletes-look-like/

Fitness, Science

A Toast to Jens Bangsbo and Peter Krustrup

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I recently made the decision to go back to school, and as part of my coursework I enrolled in an Advanced Exercise Physiology class.  One of our assignments for the class asked us to identify 2 prominent scientists in our preferred area of study, and to discuss their contributions to this area of study as well as to the field of exercise physiology as a whole.

Of course, I have only ever had one preferred area of study in the field of exercise physiology, the study of the science of soccer.  In this particular area, the logical choices as the most prominent sports scientists were Jens Bangsbo and Peter Krustrup.  Together, they have authored hundreds of scientific studies done on soccer players and teams, as well as several books.

Both Jens Bangsbo and Peter Krustrup have been huge sources of inspiration to me in my career.  I was thrilled to receive news earlier this year that the abstract from my latest research project involving high speed harnessed treadmill running had been accepted for an oral presentation at the 8th World Congress on Science and Football, happening in May of this year and being held at the University of Copenhagen (the school at which both Jens Bangsbo and Peter Krustrup are professors of exercise physiology).  I thought it would be fitting for me to post my school assignment, which focuses on and summarizes what I believe to be one of their most important contributions to science and soccer: the creation of the Yo-Yo Tests.  Here it is below.  I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.

The physiology of soccer is a subject that has always been of great interest to me.  I grew up playing the sport and now earn a living as a soccer-specific strength and conditioning coach, so I have always felt the need to learn as much as I can about the science – and specifically the physiology – involved in the sport.  Over the course of my ten-year career working in soccer, I have discovered that there are several prominent sports scientists conducting research on individual players and teams at all different levels of the sport.  Among them, two people stand out as being the most prolific and having done some of the most meaningful and influential research in this field: Dr. Jens Bangsbo, PhD., and Dr. Peter Krustrup, PhD.  Both of these sports scientists have conducted research at and continue to work as professors at the University of Copenhagen in Copenhagen, Denmark.  This paper will briefly summarize some of the main research done by both doctors, and how this research has contributed to the study of exercise physiology related to the sport of soccer.

Jens Bangsbo has published hundreds of scientific studies on soccer, and also authored several books.  Peter Krustrup has worked with Jens Bangsbo on a number of scientific studies, and also published many studies on his own.  For the purposes of this paper, I will be summarizing the research that Dr.’s Bangsbo and Krustrup have done together.  Among their most notable work includes the development and subsequent researching of soccer-specific versions of the Leger-Boucher test (commonly called the “beep test”), the Yo-Yo Tests, used as a means of assessing soccer players’ aerobic and anaerobic capacity.  Three different versions, or “levels” of the Yo-Yo Tests were developed by Dr.’s Bangsbo, Krustrup, and their colleagues at the University of Copenhagen: The Yo-Yo Endurance Test, the Yo-Yo Intermittent Endurance Test, and the Yo-Yo Intermittent Recovery Test.  Dr.’s Bangsbo, Krustrup and their colleagues have conducted numerous studies that have examined the effectiveness, validity, reliability, and reproducibility of all three levels of the Yo-Yo Tests (Bangsbo et. al., 2008,    Bangsbo et. al., 2006, Krustrup et. al., 2003, Krustrup et. al., 2006).

The Yo-Yo Tests developed and validated by Jens Bangsbo and Peter Krustrup are an extremely valuable addition to the field of exercise physiology as it relates to the sport of soccer.  The tests have been shown to be valid and reliable predictors of performance in soccer at various levels, including youth soccer, female soccer, adult amateur soccer, and adult professional / national team soccer.  They have become the most commonly used tests to determine the aerobic and anaerobic capacities of high level soccer players (professional and national team) in the world (Buccheit & Rabbani, 2014).  Furthermore, because of this extensive use of the Yo-Yo tests in soccer, countless other studies have been conducted using the tests, including some which have examined the physiological responses to the test in soccer players.  One recent study done by Hammouda et. al. (2013) reported significant increases in physiological markers of muscle damage (including creatine kinase, myosin ATPase, and lactate dehydrogenase), in young soccer players immediately following completion of the Yo-Yo Intermittent Recovery Test Level 1.  Studies such as this one serve to highlight the importance that the contributions that Dr.’s Bangsbo and Krustrup have made, as they demonstrate other scientists’ interest in studying all aspects of the tests which they created.

I have personally used the Yo-Yo Tests for over eight years now, during my work as Fitness Coach with the Ontario Provincial Soccer Teams, Canadian National Women’s U17 Team, the Toronto FC Academy Teams, as well as thousands of athletes training with my company, Soccer Fitness Inc.  During all of my years using the tests, I have always found them to be very useful in determining the physical fitness of the players I worked with, and also especially useful in assessing the effectiveness of the training interventions I used.  Myself and a lot of other fitness coaches working with soccer players around the world owe a debt of gratitude to Jens Bangsbo and Peter Krustrup for their contributions to the science and physiology of soccer in general, and the development of the Yo-Yo tests in particular.

Fitness, Injuries, Science

“What Happens When the ACL Tears?” – from elarasystems.com

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The anterior cruciate ligament, or “ACL” is a commonly injured area of the knee in soccer, as well as in many other sports.

We were recently contacted by Elara Systems Inc., a full-service design studio based out of California that works with medical and performance specialists.  They have sent us  a recently created a new animation showing the process of an ACL tear. Given that this is one of the most common injuries in soccer and almost always forces a player out for extended recovery times, I thought it would make for an interesting post in our blog.  Below is a link to the video from the http://www.elarasystems.com website:

http://www.elarasystems.com/what-happens-when-the-acl-tears/

I’d love to hear your thoughts about this topic.  Drop me a line here to get the conversation started.