Before the shooting of The Matrix, the actors were supposed to undergo 4 months of training because the stunts in the movie required special flexibility. It was twice as difficult for Reeves because he was restoring his health after a neck surgery at that time. He had 2 damaged disks — one was compressed and one was completely shattered. This meant that whenever he wanted to turn his head, his shoulders and chest would follow due to limited flexibility. Reeves once said that thanks to this movement, he looked dynamic and it’s why he continues to get so many roles in movies featuring martial arts.