CLEVELAND — When Kentucky’s basketball team emerges from timeouts, the last coach to speak to players tends to be not John Calipari but John Robic, his assistant. As the huddle breaks up, Robic grabs as many players as he can and shows them a diagram of the court on a whiteboard, walking them through what is about to happen one more time.

Robic is hands-on before games, too. He sits and watches both teams warm up. He runs drills for the guards, throwing hard passes in suit pants and dress shoes. He takes copious notes on his copy of the opponent’s roster. Calipari, by contrast, usually emerges only a few minutes before the national anthem.

These roles partly reflect the personalities of the two coaches, who are in their 17th season together. Calipari is extroverted and boisterous; Robic is introverted and dry. Calipari’s expressions are dynamic; Robic has a steady gaze. Calipari has carefully slicked-back black hair; Robic has a mop of blond and gray.

The division of labor is partly strategic. If Calipari had tried to do it all, he might not have led Kentucky to three of the past four Final Fours or to a 36-0 record this season entering the N.C.A.A. tournament’s round of 16.