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Dean Kriellaars

Dean Kriellaars

Dean Kriellaars, PhD, CEP is an exercise physiologist that works in rehabilitation, and in high performance sport. RSS

Substance Use In Soccer

Written by on February 15, 2011 | 8 Comments »
Posted in Coaching and Sports Science

We are all interested in cheaters in sport – as a curiosity, or actually being interested in weeding them out. Improving sport by deterring cheaters is one thing, but from my experience we could improve sport to a greater extent by reducing the use of non-performance enhancing substances.


A staggering 75% of young male soccer players are binge drinkers; drinking 5 more or pints a night between 1X/week and 1X/month. Not really any different from any other team sport such as hockey, rugby or football. So what is the issue?

If you think about this behavior, and especially from a coach’s viewpoint, you have to wonder, and possibly be a bit bewildered. If performance athletes binge drink on one night and the next day they are are tested on field, about 19 of 20 players will show a drop in performance.

My experience tells me this, sadly, there is very little research on alcohol effects (hangover) on athletic performance. Certainly there is clear evidence that while drunk – you can’t perform.

So, if I am right,  an athlete that binge drinks once a week will basically throw away 1.5 to 2 days of quality training per drinking session. This is self-imposed, alcohol induced flu.

So, at a rate of 1X/week, this would total a whopping 104 days a year of ETOH flu! So when coach asks for 100%, the binge drinking player responds “I will give you 70%”.

Never mind the financial burden of drinking this much, the long term health consequences of binge drinking, or even the stupid injuries athletes incur off the field of play while drunk. Tragically, alcohol abuse is still one of the greatest causes of athlete death.

I have long been an advocate of removing one’s weaknesses to become a stronger player. Alcohol misuse and abuse is a weakness. We should address it face on.

I am not asking players to be alcohol free, but consider the impact of it. I have athletes consuming vitamins and supplements so they don’t get sick a few days a year – but paradoxically they get hammered weekly or monthly.

Let’s think this through and move our so-called performance athletes in the right direction. Have the chat. Athletes KNOW it is performance degrading.

They need consistent and persistent messaging from coaches and parents – please – no more “head in the sand”.

Protein Powders and Creatine Monohydrate

The consumption of protein powders (50-80% of players) and creatine monohydrate (up to 45%) is staggering among the young male athletic population.

All wanting to look buff and maybe have a bit more muscle to perform on field. Athletes pay too much attention and use too much of their financial resources on these products, when they should be devoting their limited resources to getting “consistent, quality training with good rest and nutrition”.

Protein consumption for an athlete should range  between 1.0 and 1.8 grams of protein per kilogram of body weight per day. Most meat eating young males are already in that range.

Sadly, the number one resource person identified by athletes for the use of supplements and vitamins is the “trainer” – the least qualified person to provide advice on this topic.

I accept that every athlete is looking for an “edge”, but we all need to help them redirect their efforts to known performance enhancers. I am not anti-supplementation – I just like to focus the athlete on behaviors with the greatest returns.

I always start my talks with athletes about supplements with “We can talk about supplementation after we have achieved consistent quality training with good rest and nutrition”.


The vast majority of athletes KNOW they are sleep deprived. Good sleep involves adequate sleep duration (7.5-8.5 hours, 7 days a week) and sleep quality (not restless, deep).

Sleep deprivation leads to a lack of focus and decreased motivation.   Athletes will spend plenty of time playing Call of Duty Back Ops and populating Facebook till all hours of the night.

However, they do little to remedy their sleep problems and spend tonnes of time and limited dollars on protein concoctions.

Athletes often focus on practices and behaviors which provide little benefit to themselves, while ignoring well known basics like sleep and performance oriented nutrition.

Rejuvenation of the athlete between training sessions and games is vital to the success of the team.

If exercise is prescribed then rest must be prescribed, and this includes sleep. FYI: Alcohol and chew use decreases sleep quality.


The World Anti-Doping Agency has marijuana on the list of prohibited substances for Olympic sports.

In fact, the number ONE substance that athletes test “positive” for is marijuana.

Dwarfing steroids by a whopping 14:1 ratio!!! That is 14 athletes get caught for marijuana while 1 gets caught for an anabolic agent (steroid).

About 35% of 16-18 year old youth uses marijuana and about 70% of the time it is consumed at a party.

Interestingly, despite the fact that athletes in North America don’t smoke tobacco, they will smoke pot (or eat hash brownies) at exactly the same rates as their non-athletic peers.

Pot is not performance enhancing, it is simply against the spirit of sport and harmful to the athlete.


Baseball is renowned for the use of smokeless tobacco by it’s players (55%). Interestingly, hockey now has about 50% of young males (15 to 21 years old) using chew.

Rugby nearly 40%. The use of chew is growing rapidly in American football.

The use of smokeless tobacco products in soccer is not well studied – but at the rate that it is invading these other team sports I would not be surprised that it is growing in soccer as well.

Talk to your athletes. Tell me your stories. Chew is a very addictive habit and has many downsides.

Substance Use in Soccer

How many one goal games have you been on the losing side of? Well, it is changing practices like the ones mentioned in this article that just might make that one goal offset work in your team’s favor.

If you add up the financial outlay of athlete consumption of alcohol, protein, supplements, chew and marijuana per year – the total for a team is staggering!

This represents a misdirection of resources. If you want to be a performance athlete, then one has to focus on what is known to help athletes – consistent quality training with good rest and nutrition (along with great coaching).

In soccer, it is not really about the cheaters, it is about athletes cheating themselves of performance through the inappropriate use of substances.

P.S. This article has used male statistics on substance use. For reference, the average female athlete does not supplement with protein and creatine, takes multivitamins, has a slightly lower binge drinking rate,  about the same pot use, had similar disordered sleep levels, and almost no chew use.

Soccer and Physical Literacy

Written by on February 2, 2011 | 7 Comments »
Posted in Coaching and Sports Science

There are many movements that we see in competition, that we don’t see much of in scrimmage, and we rarely see in practice. Some of these movements have high injury rates such as colliding with a player during a “full on” header, or the dreaded contact during a full speed “50-50” ball.  I wonder to myself sometimes … are we doing enough to develop players to deal with these circumstances both safely and effectively?

Physical literacy is a relatively new concept and has been championed by Dr. Margaret Whitehead out of the United Kingdom. Her website contains plenty of background on its history.  Just like the United Nations wants every person in the world to be literate (read and write), the basic premise behind the  physical literacy movement is that all people should have the proficiency in movement skills, and confidence to use them to participate in physically active leisure time pursuits. Great idea! As a bit of a digression I have to say that I have observed that “the more literate a society becomes, the more physically illiterate it becomes”. But what does physical literacy have to do with soccer?

When you take a look at soccer, we certainly have drills that develop many fundamental movement skills in players. I dare say we do this very well in young men, and just ok to poorly in young women (this is another topic altogether!). What we lack in football are drills that develop proficiency in skills like collision avoidance, stumble recovery after collision, safe falling and sliding, fall recovery, landing from a leap after collision (two up for a header), etc. When you look at a sport like Judo, everyone wants to learn how to toss the other person. BUT no judo coach will teach you how to do a throw a person without first teaching you how to fall. I think we in soccer can take a lesson from judo.

Over 70 percent of soccer athletes are injured “in competition” with a vast majority during contact with another player. We need to address this. At the higher levels of soccer, players are assets and people (hopefully people first). Protection of the player and the team asset is critical to team success.

Developing comprehensive physical literacy in the soccer player may be the key.

I propose that we look at our game footage and take an inventory of skills that are NOT being drilled but are executed on the field of play. Then we use basic exercise and coaching science principles to develop training programs  to become proficient at these skills out of the competition setting – in practice.  We all know it takes hundreds of training  hours to become proficient at a skill – it is actually said that it takes 10,000 hours to make an Olympic Champion.  This means that without repetition there is no learning – no skill acquisition. We should not leave skill acquisition to game day!

Many years ago,  I added core exercise to help athletes not be pushed off the ball, run faster, have better throw ins, etc.   Just a few years ago I started to add drills which progressed collisions and full contact movement with other players. I just started teaching athletes “how to take a fall”. NO not how to draw a yellow card, but actually how to fall and not get injured. We just started drills to teach players how to collide for a header and land safely. I would love to hear from you if you use drills to develop this type of physical literacy.

Every player should have a full movement vocabulary – the set of skills necessary to succeed in the sport. We as coaches and exercise professionals have an opportunity to not only reduce injuries with this type of physical literacy approach, but also add to the beauty of the game by developing  confident players with a comprehensive range of proficient skills.

I think the Physical Literacy movement has something to it. I am definitely on the band wagon. It is worth a look.

Other physical literacy resources:

Canadian Sport For Life

Physical and Health Education Canada

The CORE of it.

Written by on January 3, 2011 | 3 Comments »
Posted in Coaching and Sports Science

These days, training the “core” is a fixture of fitness programs for both developing and mature athletes. But what exactly is the core? And what does core exercise do for the athlete? One thing is for certain, modern day core exercise has moved well past the old “AB” workout.

Core exercise developed over the past decade or so. Originally, people in therapy circles developed and adopted trunk stabilization exercises to aid in the prevention of, or recovery from, back injuries. This trunk stability movement expanded beyond the therapeutic realm into the performance world, and the age of core exercise was established.  The term “trunk” was replaced with “core” to include not only the trunk but the pelvis too, and the objectives of core exercise were expanded to include performance enhancement, as well as injury prevention.

One of the basic premises underlying core workouts is that these exercises will aid in the development of core stability. Having good core stability allows the upper and lower limbs to move more effectively upon a stable trunk (and pelvis too), or conversely permits a person to maintain a stable trunk in the face of external forces like a push or a pull. We even believe that an athlete with good core stability will be able to accurately position their limbs while darting through traffic on the pitch, possibly leading to lower likelihood of injury by  avoiding certain “risky” body positions.

Now, it is vital to understand that being stable does NOT mean having a rigid trunk or fixed pelvic position. We don’t want our trunk to be like an oak tree, and we don’t want it to be like a willow either. We need the trunk and pelvis to provide the appropriate foundation for movement of our limbs – whether that be for a throw in, for a corner kick, a collision, or even a header. Research studies clearly show that during limb movement the trunk muscles are not contracting isometrically to hold the trunk still, rather the trunk muscles are undergoing highly coordinated concentric (shortening) and eccentric (lengthening) contractions in response to the limb motions. The trick is to “teach” the nervous system to coordinate the trunk with limb movements through repetition, so that these systems work cooperatively in the production of movement.

Just like the goals of basic resistance training programs, core exercises for the beginner are aimed at developing strength and endurance of the core muscles. We need the muscles to be able to respond to a call from the nervous system, and if they are weak they will not respond appropriately even if the brain asks them to do the right thing! So strength and endurance training of the core is the first step in achieving core stability. Sadly, many stop at core strengthening – a two minute front plank is not the endpoint! To reach the nirvana of core stability, a key feature must be established through progression of basic core exercises. This feature is a quintessential element of core stability and is termed perturbation management. Perturbation management refers to the ability of the trunk to resist a disturbance from an external force (contact with another player) or through movements of the upper or lower limbs.

Once basic core strength and endurance are established, progression of core exercises must include movement elements which create both expected and unexpected disturbances or perturbations that have to be managed by the trunk. To use a very high performance example, the stability of a modern combat jet aircraft is not tested during straight flight but rather during high ‘g’ maneuvers. In the same way, advanced core exercises with perturbations develop the appropriate stability responses of the trunk and pelvis during cutting maneuvers in the athlete.

A very simple example of a core exercise progression which shifts from a strengthening focus to a low level perturbation management theme is as follows. Many exercise specialists provide athletes with the front plank exercise.  Certainly this provides a suitable stimulus for muscle adaptation to obtain improved strength and endurance.  Once the basics of the front plank are achieved, then we simply add an “up up down down” movement component where the athlete rises from elbow support to one hand, then both hands and returns to plank position one arm at a time. This variation of the front plank creates a demand on the trunk to be stable in the face of limb motion. With good feedback, the athlete can learn to activate the trunk muscles in concert with the limb motions. With repetition the nervous system creates a better orchestration of all the muscles during movement. This process of programming the brain to respond appropriately is partially achieved through a process of neural plasticity (changing the ways neurons communicate with one another).

Many athletes focus on strength of major muscle groups, for instance developing greater upper body strength so they aren’t so easily pushed off the ball, or can force another off the ball. Many upper body exercises have the trunk stabilized on a bench or pad during exercise resulting in an inadequate stimulus for neuromuscular adaptation of the core. This leads to a weak link. There are many athletes with good upper and lower body strength that  are unable to transform this into performance on field, often the core limits the ability to develop of-field power.

With regular and intelligently progressed core exercise, we in the exercise science field believe that this will result in faster running, higher ball speed during kicks, improved kicking accuracy, better header ability, improved ability to stay on the ball during traffic, stronger more accurate throw-ins, better collision and stumble recovery, and lower injury risk.

With the new year upon us, if you haven’t got CORE working for you, maybe it is time to make a new year’s resolution to add it to your routine. It takes 5 minutes, 3-5X a week to develop a good core. Send me an email and I will send you a introductory core routine.

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