During his active career as a surgeon Haider in the box of trainer-coach. As twenties he went abroad at his own expense, whose objectives have been to collect as much as possible, hockey knowledge. So was Haider in 1989 to witness the tournament for the Intercontinental Cup, where the Dutch team led by coach Hans Jorritsmaparticipation at the hockey World Cup, forcing more than half a year later in Lahore (Pakistan).
Practical experience did Hendriks on at big leaguer Amsterdam as an Assistant to head coach Joep Brenninkmeijer. In 1995, he was given the opportunity to stand on its own two feet at HGC. With the club from Wassenaar Haid won immediately the League title (1996) in the Big League. In that same season added national coach Rafik O.him as an Assistant to the Dutch selection.
That was the beginning of a successful collaboration: for more than half a year later Netherlands won the Olympic title at the games in Atlanta (1996), followed by winning the Champions Trophy (1996 and 1998) and the world title (1998). After Oates ' farewell (december 1998) followed Haider his teacher on.
To his authority, however, was challenged by several experienced players, including goalkeeper Ronald Jansen and midfielder Jacques Brinkman, because they were of the opinion that Haider to perfectionist attitude on relevant today. Despite internal struggles, the team defended in Sydney (2000) the Olympic title, after which Haider by order of the then Board of the hockey Federation had to pay the price for his alleged lack of leadership qualities: his contract was not renewed.
After not long after a number of guest training in Pakistan have cared, joined Haider in March 2001 in the service of the Spanish hockey Federation. He started behind the scenes, as technical director and coach of Young Spain, and took over after the WORLD CUP hockey (2002) the lead over at the somewhat impoverished hit Spanish A-selection. Haider won the Champions Challenge (2003), the Champions Trophy (2004) and the European Championship (2005).
In december 2008 he was at NOC * NSF Sports Dome the successor of Charles van Commenee as technical director and chef de mission for the 2012 Summer Olympicsin London and the 2014 Winter Olympics in Sochi.