When Ernie Els launches towering drives onto the deserted range at the Bear's Club in Jupiter, Fla., three weeks after his electric victory at the Open Championship (see related article), he makes full, graceful passes that look the same as ones from his U.S. Open win at Oakmont in 1994. "My swing hasn't really changed, but occasionally problems just creep in," he says. "You adapt so quickly as an athlete, and you go into bad habits overnight." In Els' case, the compensations began in late 2005, when he came back from a ruptured ACL in his left knee. Instructor Claude Harmon III could still see them when he and Els started working together in the fall of 2010. "He worried about his left knee hurting him, so he backed out on shots," Harmon says. "He wasn't putting pressure on the ball the way he wanted."
In favoring his left knee, Els unconsciously shifted his ball position forward and closed his stance. His swing didn't look much different, but it became much more reliant on hand action and timing, and he lost significant distance--almost 10 yards off the tee from 2005-'09, in a stretch when many players picked up at least 10 yards from new equipment alone.
Eschewing cutting-edge teaching tools like force plates and K-Vests, Harmon used old-fashioned video to help Els make some subtle tweaks. "We've been working on the same things for more than two years--ball position back, alignment more open and the club more in front on the downswing," Harmon says. "His miss used to be a quick hook with his irons and a block with the driver. Now he feels like he's getting on top of the ball with his chest, and he has room to bring the club down from a wider position and extend through impact."
Feel is the operative word. Els is one of the least-technical players on tour, and he processes swing changes with his eyes, not measurements. "In an era when everybody wants data, he's a film guy," Harmon says. "We try to attach feels to what he sees. We'll play something in slow motion three or four times, then play it at regular speed, and he'll say, 'I got it.' "
Els himself came up with his latest adjustment--a Nicklausian lift of the left heel in the backswing--as a way to feel that he was getting behind the ball. "From a good, solid fundamental base, you can put some speed behind your swing," Els says. "You can be more aggressive."