In addition, Louisville Slugger (www.slugger.com) makes its Air Inertia models, which cost about $250 and have an inner chamber of nitrogen to support the bat's walls. And Easton (www.eastonsports.com) offers its ConneXion line of bats (also in the $250 range), which feature an aluminum shell bonded to a graphite core -- which improves the strength and durability of a bat.

Sidebar: Seventh-Inning Stretch

1. Hamstring

Jim Wharton, Exercise physiologist and coauthor (with his son, Phil) of "The Whartons' Stretch Book" (1996), has seen a parade of corporate softball players limp through his Manhattan office. "In terms of staying loose," he says, "softball and baseball are the most challenging sports, because you stand around for a long time, and then suddenly you have to run like a sprinter."

Smart softballers, says Wharton, stretch before they start running and sliding. Begin with a pregame hamstring stretch: Grab some outfield, and lie on your back. Bend one leg at a 90-degree angle. Then slowly raise the other leg toward your head, in a straight, locked-knee position. Put one hand on the back of your thigh to guide the leg; put the other hand on the back of your calf. Hold each stretch for a second or two. Wharton recommends 10 reps per leg.

While standing in the dugout between innings, lift each leg (with the knee locked) to about waist height. That might be enough to prevent you from straining a hamstring when you finally come to bat and have to leg out an infield single.

Coordinates: $15. "The Whartons' Stretch Book" (Times Books); www.randomhouse.com

2. Groin Muscle

Spring is the season for groin pulls -- that is, straining the adductor muscles that run along the inside of your thighs. Michael Alter, stretching researcher and author of "Sport Stretch" (1997), recommends the following exercise for softball players who don't want to pull up lame this year.

Squat, with your feet about a foot apart and your toes turned slightly outward. Put your elbows against the insides of your thighs, and push your legs outward. Hold each stretch for 15 to 45 seconds; do two or three reps.

Exercise physiologist Jim Wharton prefers the rope: Make a loop with a rope, put one foot in it, and grasp the rope's ends at hip level. Then lie on your back, with both legs extended straight out. Lock the knee of the rope-looped leg, and extend that leg out from the side of your body, leading with your heel. Push against the rope to deepen the stretch but without causing discomfort. Do 10 reps per leg, holding each stretch for one or two seconds.

Coordinates: $15.95. "Sport Stretch," Human Kinetics, www.humankinetics.com

3. Rotator Cuff

You don't need to be a major-league fastballer to have problems with your rotator cuff -- the sheath of muscle that connects your arm to your shoulder. As muscles age and lose their elasticity, simply throwing a ball can be hazardous to your shoulder. "The heavier ball that's used in softball," says exercise pro Jim Wharton, "puts even more strain on your shoulder than a regulation baseball." To avoid injury, try this external-rotator stretch before doing any heavy throwing.

Hold your arms at your sides, and then raise them to shoulder level. Bend your elbows so that they're perpendicular to your shoulders, with forearms pointing downward and palms facing behind you. Then move both forearms back as far as you can toward the middle of your body. Do 10 reps, holding each stretch for one or two seconds.

To do a pitcher's internal-rotator stretch, extend your arms out from your sides and raise your forearms, palms facing in front of you. (Imagine being held up at gunpoint.) Press both forearms backward as far as you can. Do 10 reps of one or two seconds each.