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Information from Changing the Game Project, the Cardiff School of Sport in the United Kingdom,

US Youth Soccer, Science for Sport, the book Outliers by Malcom Gladwell, and Psych Central (World of Psychology)


"Here is the problem. I'm not afraid that my son will quit sports by the time he is 13.  I am afraid that he will be denied the opportunity to play. My son is coordinated and coachable. He LOVES sports; we can’t even have a conversation without throwing a ball back and forth! However, he's short, and not strong or fast. He's one of the younger kids in his class. His father and I were both late bloomers."


Sound familiar?


Many kids are struggling not because of a lack of skill, but

because physically they are falling behind simply due to being

the last kid to grow and mature. Anyone who has been around a

team of 13-year-old boys knows that some of them look like

10-year-olds, and some are young men. We’d never have our

U10s play our U15s, but that's the physical difference we see in

youth sports!


These differences are all part of the “Relative Age Effect” in youth sports.


Simply put, the “Relative Age Effect” is the correlation between arbitrary age cutoffs in sports and the statistically high success ratio of kids with birthdates within a few months of those cutoffs. In the 1980s Canadian psychologist, Roger Barnsley drew attention to the story of relative age in youth hockey players. Barnsley noticed that an extraordinary number of elite youth and professional hockey players had birthdays in January, February, and March. In the Ontario Junior Hockey league, nearly five times as many players were born in January than November. This held true for elite eleven- to thirteen-year-olds and again for players in the NHL.


He eventually discovered that in any group of elite hockey players, 40 percent will have been born between January and March, 30 percent between April and June, 20 percent between July and September, and 10 percent between October and December! Is it the least bit surprising to know that the age eligibility cutoff for Canadian junior hockey is January 1?



One of our biggest problems in youth sports is that we organize

children chronologically instead of developmentally.



The Relative Age Effect


One of our biggest problems in youth sports is that we organize children chronologically instead of developmentally. While this makes it easy to organize and segregate classes and teams, it puts our preadolescent children (ages five to thirteen) into situations where some may have a head start, or be denied one, because of birth month. Sure, two kids may be seven years old, but there may be eleven months of additional development for the child born in January. That difference can be huge at this age and affect them for the rest of their lives.


















When we segregate our youth athletes too soon the effects are amplified. As a result, studies in nearly every sport indicate that athletes born in the first three months after the calendar cutoff are overrepresented, and those in the other 9 months, especially the last three months, are underrepresented. For example, in the English Premier League Youth Academies, a whopping 57% of kids are born in the first third of the soccer year!


John O'Sullivan (no relation) is the head honcho at the Changing the Game Project and he says those “top” athletes are given the best facilities, the best coaching, better teammates to play with, and stronger opponents to play against. From a very young age, these “elite” kids are given a special advantage that other, oftentimes slightly younger kids are not.


Over the course of a year, the differences in performance may be small and not that noticeable. But when we project better coaching, stronger opposition in training and games, and additional positive reinforcement over ten years, we realize that we are creating athletes who have been trained better, and who have more self-confidence than many of their peers, all because of the early “tryout” they went through when they were very young. This is a result of what sociologist Robert Merton calls the self-fulfilling prophecy, where “a false definition, in the beginning … evokes a new behavior which makes the original false conception come true.” Our system often eliminates almost 50 percent of our potential elite performers because of the month they were born.


But please, do not lose hope. Below are two ways around this issue of selecting players based on chronological age versus developmental age.  


This creates a larger pool of players at the junior high and high school

level, some of which may have grown into their bodies by then. 


First, more and more leagues are following the lead of others and are working more towards the developmental grouping of players. This affords the players good competition equal to their playing level and does not force out underdeveloped players at a young age - the players that would be at a physical disadvantage playing specifically with their age group. This creates a larger pool of players at the junior high and high school level, some of which may have grown into their bodies by then. 


Secondly, the child can overcome the Relative Age Effect. Numerous studies have

found that those ‘young’ athletes who overcome the effects of relative age are

often among the most successful professional athletes based upon average salary

(in soccer), length of career (in handball) and draft position (in NHL hockey).

Researcher Dr. Joe Baker has hypothesized that “relatively younger athletes who

are able to continue in a system that may be biased towards their relatively older

counterparts may end up developing superior skills…through competing against

larger, more capable opponents during key stages of development.”


(Click here to read a fantastic review of the literature by Dr. Joe Baker and Dr. Nick Wattie on relative age in education and sport).


In a fascinating study on junior tennis players from 1994 through 2002, Piotr Unierzyski evaluated 1000 players age 12-13 in 50 different countries, a pool that included future stars Roger Federer, Kim Clisters, and others. His study found that of all these players, the ones who eventually made it into the Top 100 Professional Rakings were:

  • 3-4 months younger than the mean age for their group

  • Slimmer and less powerful than their age group

  • Usually faster and more agile than average

  • Their parents were supportive, but not overly involved


In a 2006 study on 55 Serbian U14 soccer players in professional youth teams, researchers found that when measuring skeletal age rates, the players ranked as follows:

  • 43.8% Early Maturity

  • 35.4% Neutral Maturity

  • 20.8% Late Maturity


By 2012, 16 of these players had signed top-level professional

contracts. The breakdown of the players who reached the top level:

  • 11.8% Early Maturity

  • 38.1% Neutral Maturity

  • 60.1% Late Maturity!


60 percent of the elite level professional players came from only 20 percent of the top U14s, those who were relatively young! WHAT?!?!











The good news is that many sporting organizations are trying to address relative age in athlete development (check out this article about US Soccer’s new national camps for late bloomers). If you have late bloomers in your midst, here are five suggestions from the Changing the Game Project to give them the best chance of continuing in sport and reaching their potential.
























2. Be Patient

Recognize that early sport success is not a great

predictor of later success. You should be far more

concerned that your child is in an environment that is

promoting a lifelong love of the game and is surrounded

by coaches that are positive mentors and role models.

Physical differences usually even out by the later teen

years, and then skill and the ability to think creatively

become the predictors of success, so keep focused on

those. If the young athlete has a good experience and

learns a solid basis for future success, he or she is more

likely to continue playing into the age where their bodies

catch up. 













4. Ensure they get Playing Time

Kids quit when they don’t get to play. Coaches and

organizations that are overly results focused oftentimes

do not allow kids to play. Young players must play

significant minutes in games. Being selected to the “A”

team and not getting to play is not helpful to a young

child’s development, and this often happens with

coaches who believe that your child “is not athletic

enough to help us win.” Additionally, being

"relegated" to the B team provides less training, fewer

events, lesser trained coaching, unequal competition,

and a generally worse experience. 
















We live in a sport culture that selects and promotes the “best kids’ at far too young an age. In reality, we are very often not selecting the best kids, simply the oldest and most physically developed ones.


If your child is a late bloomer, by following the 5 steps listed above you will give him the best chance of developing at his own pace, and reaching his full potential. Take the time to find the right organization and right coach for your child early on, and don’t let her get discouraged.


If they can overcome the “Relative Age Effect,” they are quite likely to perform at a very high level later on!

1. Find the Right Youth Sports Organization

Organizations that are interested in tournament championships, All-Star teams and segregating players into A and B teams at very young ages (sometimes as young as 7 or 8 years old) may not be the place for your most young athletes. Don't fall for the attractive organization with 3 uniforms, 2 different warm-up uniforms, clinics and camps advertised as free but really come from your over-the-top registration fee. That organization is more about how cool can they make the league versus how well-developed will the athletes be. Some organizations do an excellent job of

3. Educate your child

Help him understand that it is far more important to develop technique and that in all likelihood the physical piece will even out eventually. Teach them to be gritty, to compete hard, and overcome challenges. Teach them that sports development is not a sprint but a marathon, and help them see areas that they can control to become better (skill development, attitude, and effort) and not get too caught up in size and strength. Use being a late bloomer to their advantage!

5. Love Watching them Play

While I recommend you tell all young athletes how proud you are and how much you love watching them play, it is perhaps most important to let the “relatively young” kid know this. They often will struggle physically, and psychologically, when competing against bigger, faster and stronger kids, and it's up to you not to let them get discouraged. Be sure you separate your love of them from their sports performance and focus on praising them for their ability and courage to be able to compete against these ”older” kids.

providing equivalent levels of coaching and player development across entire age groups for the critical developmental years through age 13, and these are great clubs to be in. Others are results driven, and give far more resources and support to the A team at these ages (where we've already covered there should be no such thing as an A team and a B team). This is not a good place to be. The longer an organization waits to place athletes on different developmental paths with varying levels of resources and coaching, the better the chance they will develop the late bloomers.

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