Leaving aside its value as fun, about the only thing to be said for baseball as exercise is that it gets the heart thumping.

Occasionally. And for a few minutes at a time.What can you say about a game in which players mostly just stand still but have to be poised to sprint or throw a ball or swing a bat as fast as possible at any moment?

You can say the game builds character, but not the body. If anything the reverse, when you factor in strained backs, sprained ankles and pitcher's elbow.

New concepts in fitness have not been kind to baseball. The ideal games for firming up the heart and muscles are those like soccer or basketball that keep people moving. Baseball, by contrast, whipsaws the body without mercy between alert inaction and full-tilt exertion.

Players can turn baseball's weaknesses into strengths, however, by training and preparing for the game, suggests the American Physical Therapy Association.

Since kids tend to be less aware of their bodies' limitations, the advice applies particularly to Little League players getting back into action.

Perhaps the greatest hazard of the game is long-term damage to the pitcher's elbow, particularly in kids who have had little experience with sore arms.

"Kids sometimes mistake strength for proper pitching mechanics and may be trading six innings of excitement for years of arms problems," said Marty Stajduhar, a physical therapist for the Texas Rangers and a member of the association.

Incorrectly thrown curve and fast balls twist the arm and often cause small tears in the muscles and tendons around the elbow. Muscle that is torn repeatedly is eventually replaced with less resilient scar tissue. The result can be chronic pain, permanent loss of strength and an unstable elbow joint.

"Kids have to start by understanding what proper (pitching) mechanics are, and then concentrate on being in the best condition possible," said Nolan Ryan, a Texas Rangers pitcher and former Little Leaguer.

Pre-season training in mechanics, the association suggests, should include aerobic conditioning and strength-building exercises, combined with a regular stretching regimen that works on the muscles of the arms, shoulders and legs.

The physical therapy association recommends three stretches as especially valuable before a game:

- Stand just in front of a doorway and reach back both arms to hold either side of the door jamb behind you, with arms fully extended at shoulder level. Hold for five seconds, leaning forward slight-ly, and repeat.

- Grab one arm just above the elbow and pull it across the chest until the point of resistance. Hold for five seconds and repeat with the other arm.

- Pull each arm the same way behind the head.

Little League coaches and parents should discourage players from overusing their throwing arms, suggests the physical therapy association. Work into distance throwing gradually with progressively longer tosses.

After a game, apply ice to the skin of sore arms and elbows for about 20 minutes to discourage blood from leaking into frayed muscles.

- Robert Engelman is health editor of Scripps Howard News Service.