By JAMES GLANZ and ALAN SCHWARZ

In the endless quest for athletic advantage, a handful of major league baseball teams are engaged in an elaborate, largely clandestine race to master an advanced imaging technology that some baseball officials think could influence the way athletes of all ages train, perform and recover from injuries.

The technology, which has also drawn strong interest from some professional and college football teams, is an unlikely hybrid. It combines the technology that captures the human gestures at the core of three-dimensional animations like “Avatar” with advanced sensors, biomechanics and orthopedic research on the most powerful and least damaging ways to hurl a ball, swing a bat or simply run like the wind.

Essentially, the technique produces a full, three-dimensional representation on a computer that can be viewed from any direction, run forward and backward, and analyzed to calculate precise limb angles and accelerations, stresses on joints, ball speeds and the G-forces that produce them.

The technique, called motion capture, has become a recognized tool for helping athletes and nonathletes recover from injuries, said Chris Bregler, an associate professor of computer science and director of the Movement Lab at New York University.

“It’s just a matter of time before it goes into not just sports medicine but making a team better,” Dr. Bregler said.

With little public notice, motion capture technology has caught on in an increasing range of athletic endeavors. In one permutation, a company found a way to create the illusion that a football player was immersed in an EA Sports Madden-style video game. This allows an athlete to train against life-size animations whose movements are based on statistics of specific opponents. The real player — while wearing 3-D goggles — runs, jukes and throws as the EA Madden characters chase him.

Researchers have also used similar technology to create and transmit life-size images of dancers, allowing people in two locations, say New York and Los Angeles, to practice dancing together. A version of the technique called tele-immersion has also been used for a kind of “distance coaching,” in which a coach in one location can watch a team perform drills in three dimensions in another location. This has been particularly helpful to elite wheelchair-basketball teams, which find it difficult to travel.

Operating largely in secrecy, a few baseball teams have begun using the technology on a large scale with the hope of avoiding injuries, adjusting pitchers’ motions and batters’ swings and even helping players in slumps. At least three teams — the Boston Red Sox, the San Francisco Giants and the Milwaukee Brewers — are recording dozens of players, according to trainers, doctors, and technicians familiar with the work.

In football, the Green Bay Packers tested an early version of the system, according to officials with a company involved in developing the technology, and a motion capture laboratory was recently built on the campus of the New England Patriots in Foxborough, Mass.

The Foxborough program is part of the Massachusetts General Hospital Sports Performance Center, located in a large health clinic next to the Patriots’ stadium. The program, which also involves research at the Massachusetts Institute of Technology, is led by Dr. Eric Berkson, an orthopedic surgeon and team doctor for the Red Sox. He provided a glimpse of the system on the condition that he would not discuss his work for the Red Sox.

Inside the cavernous laboratory, Phil McCarthy, a lanky young amateur pitcher from Old Dominion University in Virginia who had been recruited for the demonstration, went methodically through his workout, throwing fastballs, changeups, curveballs and a dipping split-finger pitch. About 75 small white globes were stuck to his body as if he had contracted some alien disease. Above him was a ring of 20 high-speed cameras, each glowing an eerie scarlet, capturing images of the reflective globes with an infrared strobe.

The disembodied cloud of globes appeared on a large video screen, and then — flash! — a computer program connected the dots, and a sketchy but biomechanically exact twin of Mr. McCarthy appeared on screen. His windup and delivery had been captured in three dimensions, with enough detail to calculate the stress on his wrist and the angular velocity of his shoulders.

Although the Red Sox declined to discuss their use of the technology, a physician on the project, Jim Zachazewski, said: “They are a very data-driven team. This will help to take that to the next level.”

Some sports insiders predict that once the programs become more widely known, they could set off a technology race and give younger, technically savvy coaches a new edge over traditionalists.

Bill Schlough, the chief information officer for the San Francisco Giants, declined to let reporters see his team’s system or even confirm its location, but he said: “There are some coaches that see it as some sort of hocus-pocus. Are there going to be a lot of coaches like that left in 20 years? I doubt it.”

He added: “It’s not the holy grail. It’s another tool in our arsenal to improve performance.”

Trainers and team doctors are still grappling with how to use the overwhelming amount of information the analysis provides. But if an athlete is captured when healthy and performing with peak effectiveness, a second recording can effectively let the athlete “step inside” himself or herself after an injury or a slump, compare the two sequences and reveal in precise detail what has changed and how to focus rehabilitation.

By capturing dozens or even hundreds of players, teams hope to better understand mechanical problems — say, a pitching motion that puts too much stress on an elbow — and correct them before an injury occurs, said Jason Long, a biomedical engineer at the Medical College of Wisconsin Sports Medicine Center in Milwaukee, which operates a motion capture system that is used by the Brewers.

The Brewers’ pitching coach, Rick Peterson, said, “It’s getting an M.R.I. of a pitching delivery — you see everything that’s going on, how efficient the kinetic chain is.” Mr. Peterson is a co-founder of 3P Sports, a company that analyzes amateur pitchers’ motions through video.

Mr. Peterson said that at least three Brewers pitchers — Yovani Gallardo, Randy Wolf and John Axford — had made adjustments based on the motion capture system, and that “some other pitchers have had velocity increases in the minors, too.”

Perhaps the most tantalizing and hotly debated possibility is that the data will help trainers and coaches crack the code of a nearly perfect swing or the safest throwing motion and improve the performance of healthy players. But whatever the ultimate uses, the technology opens an analytic universe that is not available with standard video.

“They’re the automobile versus the bicycle,” said Glenn S. Fleisig, the director of research at the American Sports Medicine Institute in Birmingham, Ala., where much of the research that forms the basis for the new work has been done over the years. Experts in motion capture think that even with the latest initiatives, athletes are still only scratching the surface of the technology.

One of the most sophisticated applications is the system that enables football players to essentially practice against “a virtual defense,” said Rob Moore, the vice president and chief technology officer for EA Sports. “He’s getting the reps in without getting the physical punishment.”

A digital technology company called XOS produced at least two facilities, one at Marshall University in Huntington, W.Va., and another at the University of Arizona, although teams have found them cumbersome to use. XOS has terminated that program, focusing instead on a laptop-based trainer that has proved more popular, the company said.

All of these new possibilities have sparked questions on whether they could help college teams evade rules on how much athletes may train with coaches, although an N.C.A.A. spokesman indicated that no immediate concerns had been raised.

Peter Bajcsy, a research scientist at the University of Illinois and the National Center for Supercomputing Applications, said that whatever its other uses, the technology offered an unparalleled medium for capturing great athletic performances.

“If we don’t record Michael Jordan doing a slam dunk today, a hundred years from now, nobody will know how he moved,” Dr. Bajcsy said.