Past athletic performance doesn’t guarantee future results

Sunday, October 1st, 2023

Athletes who succeed in junior age categories are, for the most part, completely different from those who succeed in adult competition:

The overall pattern was that top juniors tended to pick a sport early, practice it to the exclusion of other sports, and progress rapidly. But those who made it to the top as seniors had precisely the opposite pattern: they had spent less time training in their main sport and more time playing other sports as kids, and they made slower initial progress in their main sport.


The results are clear: most successful juniors don’t become successful seniors, and most successful seniors weren’t successful juniors. One example: 89 percent of international-class under-17 and under-18 athletes never reach that level as seniors, and 83 percent of international-class seniors didn’t make it to international class at the under-17 and under-18 level. To put it another way, these junior and senior populations are 93 percent different and just 7 percent the same.

These results undermine both of the main theories of how outliers get so good—i.e. that it’s all about natural talent, or that it’s all about how much and how effectively you practice. Both theories imply that how good you are as a junior will predict how good you are as a senior, and that success at both levels is predicted by the same factors. Instead, Güllich argues that what predicts junior success—a focus on training to maximize immediate performance—might actually work against the prospects for sustained long-term improvement.


  1. Grasspunk says:

    I’ve been watching this play out in the sport of rugby, which is extremely strong in our SW France region. The best young players around 10-11yo get invited to start at a specific middle school associated with the big club. Three years later a lot have already been let go because they did not grow enough and there’s a second cohort that comes through at the start of high school. Often the let-go kids quit the sport because they had huge expectations that were not met.

    Rugby has a lot of international competition at the U20 level and it is instructive to see a match from, say, 2017 to how many made it to international level. Then you see if you could have guessed them from their match performance.

    [After "Grasspunk the math tutor" there's now "Grasspunk the assistant rugby coach and boxing coach". One day I'll write out a cheat sheet.]

  2. Bomag says:

    The late bloomer is a thing; appears to be more common than I thought.

    I’m wondering about measuring the early maturing aspect: growth plates? I suspect the top juniors are early mature-ers; wondering what percentage of early mature-ers go on to be top seniors compared to percentage of slow mature-ers. The article doesn’t cover this: if ten percent of kids are early maturers, and nine of them are tagged as top athletes as youths, time would be expected to weed them out later to match the one percent of late bloomers who become top seniors.

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