It is 4:30 in the afternoon. Your child walks onto the court looking perfectly fine. No limp, no headache, no obvious reason to adjust expectations. But something significant has already happened before the first ball is struck, and most coaches and parents never account for it.

The school day is a cognitive workout. A long one.

A review published in the April 2026 issue of the ITF Coaching and Sport Science Review puts a precise frame on why this matters for tennis. “From Brain to Court: How Executive Functions Shape Self-Regulation in Tennis” describes three mental capacities that sit at the foundation of everything we want from a tennis player: inhibitory control, the ability to resist impulsive reactions; working memory, the ability to hold a plan in mind while executing under pressure; and cognitive flexibility, the ability to shift strategies when the situation changes.

These show up in the most recognizable moments of a match. The player who stays composed after a double fault. The one who remembers the game plan when the score gets tight. The one who adjusts when the opponent changes pace. And the research is consistent: these capacities predict not just match-day performance but long-term development. One study cited in the review followed junior players for 18 months and found that those with stronger executive function scores improved their rankings significantly more than those with lower scores.

Here is the part that rarely gets named directly: these are the same capacities a child spends all day at school.

Sitting still and staying focused. Following multi-step instructions. Suppressing the impulse to call out an answer. Switching between subjects, teachers, and social contexts. Managing the low-grade stress of tests, presentations, and the complicated social world that school involves. All of it draws on the same three resources. By the time practice starts, a child has been spending them for six or seven hours straight.

Research published in the Proceedings of the National Academy of Sciences tracked the full population of Danish schoolchildren and found that cognitive performance dropped measurably with each passing hour of the day. Not because the children became less capable, but because the mental resources required to perform were progressively depleted. A 20 to 30 minute break reversed much of the decline. The same pattern holds in sport. Separate research cited by Di Muccio and Grossenbacher found that mental fatigue directly impairs physical performance by overloading the executive mechanisms involved in effort regulation, and this happened without any measurable change in physiology. The body was ready. The brain was not.

What does this actually look like on court?

It looks like a child who rushes through points and makes the same error twice without seeming to notice. An emotional reaction to a mistake that feels out of proportion to the situation. A straightforward tactical instruction forgotten three minutes after it was given. A player who cannot switch gears even when what they are doing is clearly not working. These things get read as attitude problems, lack of focus, or not trying hard enough. More often they are the predictable result of a system that has been running since morning and is now running low.

That distinction matters for how coaches and parents respond. Frustration directed at a child who is genuinely trying to hold it together does not build resilience. It builds negative associations with the sport.

What to do with this

For coaches, the most useful adjustment is simply to account for the context. An after-school session is not the same as a Saturday morning, and it does not need to be treated the same way.

Give players a real transition before introducing anything cognitively demanding. Five or ten minutes of low-pressure hitting lets the nervous system shift gears. If working memory drills are on the plan, where players hold a tactical intention while competing under pressure, those belong early in the session rather than after 45 minutes of accumulated load.

A quick check-in takes 30 seconds and gives you real information. Asking how school was that day is not small talk. A test, a presentation, a difficult social situation is a signal to simplify the structure. More repetition, less problem-solving. That is not lowering standards. It is coaching to the actual conditions in front of you.

The review also recommends using a simple mental effort scale, asking players to rate how loaded they feel on a scale of 1 to 10 before the session starts. A player arriving at a 7 or 8 needs a different practice than one arriving at a 3. It takes one question to find out.

For parents, two things are worth considering seriously. The first is food. Executive functions are metabolically expensive, and a child who has not eaten since lunch is not in a good state for the kind of demanding work tennis requires. A proper snack before practice is not a minor detail. The second is sleep. The primary way executive functions recover is through sleep, and consistent late nights do not just affect energy levels. They create a running deficit in the capacities that determine how a young player learns, adapts, and performs over time. It is one of the highest-leverage decisions a family makes, and it almost never comes up in conversations about tennis development.

Understanding cognitive fatigue does not lower the bar for young players. It moves the bar to where it actually belongs. A child who holds it together through a difficult afternoon session, resets after errors, and finishes with their effort intact has done something genuinely hard, and that is worth naming out loud rather than glossing over because the groundstrokes were not their best.