'Long-term athlete development' has perhaps never been more topical, with an ever-growing number of programmes worldwide providing training for children and adolescent athletes. Mostly there is agreement on the need for structured 'athlete development' programmes for kids who engage in youth sports. We have consensus that appropriate physical and athletic development is beneficial for kids' health, performance and long-term outcomes. Still, confusion remains among parents, young athletes and practitioners, as authorities in the field continue to hotly debate the details. Here we will attempt to cut through these debates and provide much needed clarity and context to resolve some of the confusion. As we generally agree on the 'why', we will attempt to move things forward by finding shared ground and common principles to guide the 'what' and 'how' in relation to long-term athlete development.
THE GOVERNING PRINCIPLES OF ATHLETE DEVELOPMENT...
As was aptly put in a recent presentation, @@the focus for any athlete development programme should be the athlete@@. Whilst this might be stating the obvious, too often this is lost sight of by those involved in development pathways in the sport, and the growing number of 'talent' programmes at school, club, and representative-level.
So perhaps this merits repeating: @@the best interests of the individual (i.e. the child or teenager concerned) must govern all processes and decision-making in athlete development programmes@@.
Likewise, by definition, @@long-term outcomes must take precedence over short-term results@@. Hence, long-term athlete development. Once again, this is a fundamental premise that few would disagree with. And yet, the odds are those who have experienced youth sports will have observed instances where this principle is violated.
There are many cases of myopia in youth sports, chasing the win on game day with little or no regard for long-term perspectives. Indeed there are numerous examples in different sports where policy and age-grade competition structures directly contradict governing principles of long-term athlete development.
THE GREAT DEBATES...
Taking such contradictions in practice aside, few among the key 'stake-holders' (coaches, practitioners, parents, athletes) would argue against the governing principles of athlete development we have described. All parties would tend to agree that the approach should be 'athlete-centric' and prioritise long-term outcomes. So, what exactly are we arguing about?
Essentially there are three major areas of debate and disagreement in relation to athlete development.
The first major debating point surrounds the model or system that we should employ for long-term athlete development (see a recent post dealing with the topic of training systems).
The second concerns how we should assess or evaluate maturation, often termed 'relative' or biological age.
Finally, in various sports there are diverging views on specialisation (focusing on one chosen sport) versus 'sampling' (continuing to engage in multiple sports). For example, arguments remain on what age athletes need to choose to specialise in order to acquire mastery in a particular sport, and ultimately attain elite level in senior-grade competition.
DEBATE #1 - BATTLE OF THE 'ATHLETE DEVELOPMENT' MODELS...
Until recently, the long-term athlete development (LTAD) 'model', originally pioneered by Istvan Balyi, was the predominant and most widely accepted approach. For a number of years, the popular version of the LTAD model attributed to Balyi had been enthusiastically adopted by many national sporting organisations worldwide.
In the recent period notable publications in the sports science literature have raised questions over the LTAD model as commonly employed. These authors have highlighted flaws in certain aspects of the LTAD framework. The empirical evidence underpinning particular elements of the model has also come under challenge.
Some of the authors of these publications have since proposed alternative models, including the Youth Physical Development 'YPD' model. The implication is that the 'new' model proposed should replace to the 'old' LTAD model.
Such publications 'debunking' the established LTAD approach have therefore heralded something of a shift in popular opinion. To some degree there is a trend of rejecting the LTAD model in favour of alternative approaches which have risen to prominence (including the aforementioned YPD model).
It is important that flaws in the details of the existing popular 'LTAD' frameworks and associated methodology are acknowledged. That said, it is also critical that we stop short of discrediting the wider premise of long-term athlete development.
Clearly an unwanted outcome is that LTAD as a concept falls out of favour and becomes a discredited term among authors and practitioners in field. Flaws in the interpretation and application of the LTAD model should detract from the fact the fundamental premise and central tenets of the approach are sound.
HOW DO WE RESOLVE THIS..?
There are a number of parallels here with the present debates on training periodisation. In recent times John Kiely in particular has exposed the tenuous rationale for many of the popular periodisation models. It is argued that much of what is proposed by conventional periodisation schemes is arbitrary and not grounded in physiology. However, even the most scathing critics of these periodisation models nevertheless agree on the need for planned and systematic variation in training prescription. This is of course the essence of what periodisation exists to provide. We are therefore debating the merits of the methodology and conventions that have become associated with the principle, rather than the principle itself.
Returning to the debates on athlete development models, legitimate questions have been raised over how the LTAD framework has been applied. The growing field of research in paediatric exercise science continues to generate new findings and data. These emerging insights indicate certain assertions of the original LTAD model to be somewhat flawed.
For instance, some (quite logical) assumptions on what training is appropriate at different developmental stages based on biological maturation and physiology have been dispelled. For example, it turns out interval training is actually quite effective even prior to puberty; the nature of the adaptations that result are simply different.
The reality is that any model will prove to have shortcomings over time as research fills in the gaps in our knowledge. Equally, taking a wider view (and as we have identified in a previous post) @@any system too rigidly and dogmatically applied will inevitably lead to flawed practice and adverse outcomes@@.
Much like Matveyev's linear periodisation framework, it is should also be considered that Balyi's original LTAD framework was likely intended as an illustrative example, rather than a blueprint that must be strictly and religiously followed.
The concept of long-term athlete development has value. Putting another way, we might argue that @@the main value of long-term athlete development lies in its use as a wider concept@@. Once again, principles trump methods:
We must also consider the fact that, however well-meaning, by introducing new terms we muddy the waters. Sports science and medicine as ever are plagued by issues of nomenclature; a myriad of different terms exist in the literature that essentially describe the same thing (e.g. youth physical development, long-term athlete development). This presents an obstacle and a source of confusion for the audience we need to reach (parents, coaches, and the athletes themselves).
There is a lot of value in the 'new' methodology described in the recent literature. That said, taking a wider view, it is crucial to recognise that proposing competing models to replace the LTAD model is more likely to divide opinion rather than moving things forward.
Allowing arguments on details of application and specifics of methodology to spill over risks the wider concept of long term athlete development becoming discredited in the eyes of practitioners, coaches, parents and athletes. It might serve us better to focus on the principles we share agreement on. Shared purpose will allow the practice conducted under the banner of 'LTAD' to evolve.
DEBATE #2 - METHODS TO ASSESS MATURATION...
The central issues concerning the assessment of 'biological age' or relative maturation in youngsters revolve around ethics and practicality. What might be considered best practice or 'gold standard' from an academic viewpoint does not necessarily equate with what is realistic in a practical setting. This is not a new problem. For instance, standard methods in paediatric research to evaluate maturation based on markers of puberty and secondary indices of sexual development, such as Tanner stages, have long been plagued with these issues.
Similarly, the present 'gold standard' measure of maturity involves assessment of 'skeletal age' via X-ray. Clearly there are issues of practicality with this mode of assessment, given the cost and difficulty getting access to specialist equipment and staff. There are also ethical issues of routinely exposing children to X-ray radiation without any medical cause to do so.
To safeguard both the child and the practitioner, indirect assessments of biological age are therefore the norm. Typically these methods yield predictions and estimates based on simple measurements, such as height and weight.
Age at peak height velocity (PHV) is one of the more popular 'field' assessments which measures body mass and height, and uses regression equations developed by Mirwald and colleagues to derive individual estimates for males and females, respectively. The reference point used for the maturity estimate is 'peak height velocity' - i.e. the steepest portion of the growth curve corresponding to the greatest rate of growth in height. This 'PHV' reference point is more commonly termed the 'adolescent growth spurt'. The 'maturity offset' values derived therefore refers to the how many (decimal) years the individual is away from this reference point. For instance, +1.1 years indicates that the individual is 1.1 year past the age they are estimated to have hit their adolescent growth spurt (age at PHV).
The regression equations developed by Mirwald and colleagues are based on the original growth curve data of a sample population of children and adolescents in Canada. More recent attempts to validate these regression equations in other populations in different parts of the world have reported discrepancies in predicted versus measured values for the respective populations. This is not entirely unexpected. Naturally, genetics will differ between populations, and environmental influences on growth and development inevitably exist in different parts of the world.
Another potential issue recently reported with this method is that the degree of prediction error may depend on the athlete's age and how close they are to their adolescent growth spurt at the time of assessment.
In response to the issues and sources of prediction error identified in the literature, some authors are steering away from Mirwald's age at PHV assessment in favour of other approaches.
One of the alternatives being championed involves prediction of adult height and related estimates based on standing height data recorded from both biological parents. It should however be noted that this method may also prove problematic, depending on different factors such as the particular family circumstances of the young athlete.
CAN WE FIND RESOLUTION HERE..?
An important starting point is to recognise that any indirect mode of evaluation represents a compromise. By definition any indirect method has limitations; this is accepted because it also provides a pragmatic means to gather data, avoiding ethical and practical issues.
The other governing principle in choosing an indirect measure of biological age is to consider how we will apply this information.
Let me give you an example. The athlete development programme I run operates using three 'bio-banded' tiers. These bio-bands are quite broad. For instance, as depicted the figure below, the middle tier is around 2-2.5 years in 'width'. The lower and upper tiers are broader still, encompassing quite a wide range in terms of chronological ages.
With this approach, athletes' maturation assessment data is employed in two ways. The first is to guide which of the three tiers each new athlete is assigned to upon entry to the programme. The second application is as an objective means to track readiness to transition to the next stage, or 'bio-band', as the young athlete progresses over time.
Once again, the structure of the programme dictates what we need from the maturation assessment. Returning to the 3-tier 'bio-band' athlete development programme outlined above, given the broad groupings employed we essentially just need our maturation estimate to identify which 'ballpark' the athlete is in. For instance, if we were employing more narrow bio-banded groupings (e.g. 1-year increments), there would be a need for 'higher resolution' - demanding a greater degree of accuracy and narrower confidence limits from the measure chosen.
As it stands, the mode of assessment I personally choose to employ involves the aforementioned Mirwald regression equations. Along with date of birth information (captured on entry to the programme), we periodically measure body mass, standing and seated height to derive the measures we need to input into the respective equations for males and females.
At this stage we should note that it is perfectly acceptable to use the alternative method that derives estimates from (biological) parental height data. Other programmes in different parts of the world choose to use this method. Once again, it comes down to preference and individual judgement. You simply need to weigh up practicality and logistical factors. And of course we should consider context, particularly with respect to how the data will actually be used.
There are other important points to note here. Whilst the athlete's maturation data is considered when assigning an athlete to a respective bio-banded group, or deciding whether to transition them to the next stage, equally it is not the only information considered.
Firstly, the assessment process is not a single snap shot: we continue to take serial measurements to track changes in height over time. Consider a young male who is estimated to be at a biological age marking him as ready to transition to the upper bio band. If his serial measurements - and my own observations - indicate that the athlete is still growing at an accelerated rate then we will not transition him, regardless of what the maturity assessment indicates.
This example illustrates the second important point: it is incumbent upon the practitioner to interpret the maturation data derived for each athlete. Once again, it is critical to consider context, and be mindful of the limitations of the assessment mode and 'confidence limits' of the estimates derived.
Returning to the programme I presently run in New Zealand, clearly we must bear in mind that the demographics of the population are somewhat different to the original Canadian sample the regression equations are derived from. A related consideration is ethnicity. Once again, a limitation of the regression equations is that it will likely cope less well with ethnic groups other than white-European. On that basis, I interpret the values derived with a great deal of caution when assessing Maori or Pasifika athletes, those of Chinese or Korean descent, etc.
DEBATE #3 - SAMPLING VERSUS SPECIALISATION...
Our final point of contention differs somewhat to the debates described previously. On the topic of early specialisation most authorities in the academic fields of paediatric exercise science and long-term athlete development are largely in agreement. The risks of early specialisation with respect to overuse injury and restricted development are well documented. Conversely, the potential benefits of sampling a diverse range of sports during the developmental years are widely identified.
The discrepancy here relates to what is overwhelmingly recommended, versus what can practically be achieved or supported when faced with the realities of competitive youth sports in the present era.
Let us state from the outset that the arguments in favour of 'sampling' multiple sports in preference to concentrating on a single sport (i.e. early specialisation) are many and all very sound. Not least from the viewpoint of developing global athleticism (see a recent post defining what constitutes 'athleticism'), the potential benefits of exposing a young developing athlete to a wide and diverse array of sports and 'movement environments' are considerable.
HOWEVER, as stated, there are also some realities to face here. There are numerous examples of youth sports which now afford the opportunity to practice and compete year-round. Given these opportunities exist, we must consider that many kids will choose to engage in these sports year-round, regardless of what may be recommended. For these kids the time left over to participate in other sports is likely to be severely restricted.
One illustrative example is ice hockey in America, as discussed in a recent podcast hosted by Rob Gray with Prof Joe Baker (recommended listening for anybody with an interest in talent ID and development). In the past, ice hockey was a seasonal sport. For instance, if you grew up in Canada you would play ice hockey (perhaps outdoors) in the winter, and then find another sport in the summer months. Now there are organised spring/summer leagues, in addition to the main winter season, providing the opportunity to play (and be scouted) in the period in between.
However we might rail against this, often these are simply the realities we face. The growing number and severity of injuries reported in youth sports underlines that we must be prepared to move beyond the standard guidelines in these cases. For instance, it was reported recently that ACL reconstruction surgeries among children have tripled over the past 15 years.
Given the stakes involved, @@we must meet young athletes and parents where they are@@. To this end, it is time to propose compromise solutions to cater for those young athletes (and parents) who fall into this category of year-round single sport participation. What is recommended as the 'ideal' for the majority, i.e. sampling a range of sports perhaps until late in adolescence, may also not be manageable in practice or even beneficial in some instances.
IS SAMPLING ALWAYS THE ANSWER..?
A strong case for 'sampling', or multi-sports participation, can be made from a physical development, motor learning, and even psychosocial development perspective. However, this does assume that there is spare capacity in the young athlete's schedule to accommodate adding other sports.
There are certain practicalities to consider when attempting to participate in multiple sports. For instance, practices and competition seasons for the respective sports may overlap. Inevitably there will be some trade-off involved; generally something has to give. Whatever might be recommended, often what is sacrificed is adherence to physical preparation sessions. In this case, participating in additional sports is unlikely to bring the desired benefits if it is at the cost of being able to fully participate in general physical development.
Finally, we must also be mindful of managing overall load - and the how it is distributed within the week. Once again, the potential benefits must be weighed up against the risk of overwhelming the athlete and predisposing them to overuse injuries that are common in this population.
We must therefore consider that there will be cases where the young athlete's existing scholastic, sporting, physical preparation and other commitments simply do not support adding another sport.
ALTERNATE ROUTES TO PROVIDE 'DIVERSIFICATION'...
The major benefits of sampling from motor development and sensory-perceptual perspectives stem from providing the athlete with a variety of movement challenges in different environments as they grow and develop. Ensuring continued exposure to a wide 'bandwidth' of movements and interactions during these key developmental years is critical to foster global development of athleticism, and ultimately acquire a wider array of skills and abilities.
The question therefore is whether we can provide this diversity of motor development and sensory-perceptual challenge in another way?
Outside of sports participation, an alternative vehicle for providing the necessary diversity is the other training or physical preparation that young athletes might undertake alongside their sporting activities.
This alternate route will necessitate shifting the emphasis of physical preparation programmes delivered with youth sports athletes. At the outset we must re-frame the overall objective. It must be clear and explicit that the priority outcome is global development of athleticism, rather than more narrow goals which are bound to the sport or to the weights room.
Having clarity on the ultimate objective and associated outcomes will then inform our approach when training young athletes, as outlined in a previous post. In particular, physical preparation sessions should encompass a range of activities and challenges; and these should also deviate from what the athlete is exposed to elsewhere, such as in their sport. Hereby we can provide the requisite diversity of input and challenge to stimulate global development of athleticism.
Clearly how this is communicated to the athlete, parent and coach is critical. Sport-specific youth training programmes clearly will not fulfill the need for diversification; equally from an engagement viewpoint it is crucial that we make a compelling case for this approach. Once again, we return to the need for long-term perspectives which take precedence over short-term outcomes and associated metrics. By happy coincidence, in the short- and medium-term this approach will however also help safeguard against injury and allow the young athlete to perform better in whatever youth sport they are engaged in.
BRINGING IT ALL TOGETHER...
Having delved into the great debates of long-term athlete development, hopefully we are now closer to a way forward. Whatever the issues with the original model proposed, LTAD is an important concept and we must consider the consequences before we discredit the term. As our understanding improves, the methodology should be allowed to evolve and the rationale employed revised and updated without abandoning the concept and governing principles of LTAD altogether.
Pragmatism should also guide our selection of maturation assessments. Whichever method is chosen the limitations should be considered and the data interpreted in context. Ultimately it is up to the practitioner to apply whatever data is available to the programme in question, and use their own judgement to make informed decisions.
Finally, whilst it is important we remain vigilant to the dangers of early specialisation, we must also do what is necessary to reach our audience. Continuing the theme of pragmatism, where the realities of the situation demand it, we must be ready to move beyond blanket recommendations to propose alternative solutions. Where the young athletes schedule makes participation in multiple sports problematic, we should consider our approach to ensure the necessary diversification is provided in the physical preparation they undertake.
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