Eamon Devlin : "A coach (here Antonio Conte) must weigh the impact of their intervention before distracting their player" / ©Icon Sport

In just a few years, psychology researcher Eamon Devlin and his consultancy, Minute9, have become go-to advisors for the world’s football elite. From Real Madrid and Brighton to the Brazilian national team—extending even to the NBA and top-tier rugby—Devlin’s team provides data-driven guidance to high-performance coaches based on rigorous scientific research. A Gaelic football coach himself, Devlin specializes in touchline posture and demeanor. Specifically, he warns against "hyperactivity" in the technical area. "While a burst of energy can be useful for relaying a tactical instruction or sparking a reaction, coaches must realize that shouting or frantic gesturing inevitably breaks a player’s concentration for a fraction of a second. Against a player like Kylian Mbappé, that split second can be fatal. A coach must weigh the impact of their intervention before distracting their player." The consequences of over-shouting extend beyond the pitch and into the locker room. "When a coach enters the dressing room at half-time with a raspy, strained voice, our studies show that players fixate on the unusual tone of voice rather than the actual content of the message," says the psychologist.