At Everton between 2016 - 2017
Jan Kluitenberg, Fitness Coach, followed Koeman to Southampton in the summer after working under him at Feyenoord and joins him once again at Everton.
The duo also enjoyed spells together at AZ Alkmaar and Benfica.
Kluitenberg's role at Everton is to ensure the players reach peak physical fitness and is responsible for devising individual training programmes to ensure maximum physical output and prevention of injuries.
Having worked with him at four previous clubs, Koeman clearly has trust in Kluitenberg's methods and it would be hard to argue with his techniques.
Jan's role with the club ended on 24th October 2017, after the dismissal of manager Ronald Koeman.
Good luck to Jan from all at Love Everton Forum.