CHULA VISTA, Calif. (AP) _ As often as he likes, American pole vault star Toby Stevenson competes against Sergey Bubka, his idol and world record holder. In tandem, they race down the runway and fling themselves over bars more than 19 feet above the ground. That's some Olympian feat, considering that Bubka is retired.
Actually, these head-to-head duels play out on a computer screen, superimposed in digital video overlay. It's part of the latest way USA Track and Field is preparing its runners, jumpers and throwers for Athens.
Since October, USATF has been using a software program called Dartfish to help athletes evaluate their performance through real-time digital video analysis.
To Stevenson, a 27-year-old Stanford graduate, Dartfish has become as essential as the helmet he wears while competing.
``I use it until smoke comes out of the machine. It's great,'' Stevenson said after a recent workout at the U.S. Olympic Training Center in this San Diego suburb.
A few days later, Stevenson finished second at the U.S. track and field trials, securing a spot on the Olympic team.
Stevenson can review his practice jumps on a laptop within seconds of a return to earth from one of his vaults. Within two hours of a track meet, he can watch himself on an LCD projector back at the hotel. Or he can have his day's work burned onto a CD.
While Stevenson's muscles tell him one thing, the digital video might reveal something else.
``It's a big reason for my success,'' Stevenson said. ``I jump, and between every jump I watch my jump, and after practice I watch every jump on Dartfish.''
Stevenson can look at a jump in real time, quarter time, half time or frame-by-frame. He can compare up to four different jumps at once, or have two jumps overlaid to see how consistent he is.
Or he can vault versus Bubka. The technicians who run the DV program converted analog video of Bubka to digital with a few extra steps outside of Dartfish, which grew out of a Swiss company in 1998 with early success in ski racing broadcasting.
``Obviously it's not Dartfish alone, but yeah, I increased my PR (personal record) 10 inches this year,'' Stevenson said. ``I've got the Nos. 1, 2 and 3 jumps in the world right now.''
``It's a comparison tool unlike nothing else,'' says Jen Davidson, sports science technical coordinator for USATF. ``The possibilities with this are kind of infinite.''
A college high-hurdler, Davidson used to use explosive force to launch a bobsled down an icy track. She was unceremoniously dumped by driver Jean Racine just two months before the 2002 Winter Olympics in her hometown of Salt Lake City.
Now she's clicking away with a mouse, making sure the DV analysis gets to the athletes.
Davidson and her staff videotaped every competition at the track and field trials in Sacramento and will be at the Olympics from Aug. 13-29. Since access is extremely limited, they'll have to render from international broadcast feeds in lieu of taking their own video.
``In Athens it might actually be a better training tool than it is review of competition,'' said Davidson, whose software runs on the Windows 2000 and XP operating systems and handles a variety of video formats.
Named after the only tropical fish with a dorsal antenna, Dartfish can overlay video of two skiers to make it look as if they're racing head-to-head.
``The training applications quickly became apparent,'' said Kristin Dilworth, director of education and Olympic support for Dartfish.
Dilworth formerly worked for the USOC and estimates that more than half of America's Olympic-caliber athletes in all sports _ archers, gymnasts, rowers _ have either been exposed to Dartfish or use it regularly.
Olympians aren't alone in having their movements charted and measured by computerized video tools.
The Seattle Mariners use the software on their TV broadcasts and for training. Swimmers and divers like it, too.
Davidson likes how it can help a shotputter determine his arm angle in relation to his body. Or how she can overlay vertical lines on the video, showing the strongman whether he's moving his head too much.
The company's Web site says simply: ``If you know how to move, you know how to win.''