Few experts would argue with Oriole coach Allan Johnson's insistence on the importance of mid-body strength.
"That's the core of any athlete; transmission of energy from the legs to the arms goes through the trunk," says Pat Croce, a Philadelphia-based physical therapist, athletic trainer, and consultant to professional athletes. "You can have superstrong legs, but if you don't have a strong trunk, you will lose some of that power."
"No matter what the sport, whether it's golf or playing tennis, running or even simple jogging, people with weak abdominals are at risk for low back strain or injury," agrees Dr. Charles Silberstein, assistant professor of orthopedic surgery at the Johns Hopkins School of Medicine and medical director of the Bennett Institute at Children's Hospital.
Even if you're not an athlete, a belly that bulges in front can give you back trouble; it shortens the muscles in the lower back, stretches the muscles in the upper leg, and stresses the facet joints in the lumbar vertebrae, warns physical therapist Shobha Makhijani of the Union Memorial Hospital Sports Medicine Center.
The standard stomach strengthener -- the half sit-up, done with the knees flexed, the feet flat on the floor, and the shoulders raised only part way -- is fine for the upper abdominals, according to Ms. Makhijani, but you have to work the lowers, too. She recommends a pelvic tilt: Lie on your back, with knees bent. Keeping your shoulders on the floor, press the small of your back flat and pull pelvis forward, as if you're trying to tuck your abdominal muscles under your rib cage.
"You have to maintain a flat back," she emphasizes. "As soon as you lose contact with the floor, youcause stress on the back."
Mr. Johnson prescribes a tougher series of abdominal exercises for the well-conditioned O's:
* For the lower abdominals: Lying on the back, bring knees to chest, then lower the feet almost to the floor; bring knees back to chest.
* For the upper abdominals: Lying on the back, raise legs straight up from the hips, keeping the knees slightly bent. Raise shoulders off the floor and try to touch the toes.
* For the oblique abdominals: Lying with the left knee bent and the right leg crossed over it, with the right arm out to the side and the left hand is behind the ear, raise the left shoulder and try to touch the elbow to the right knee. After 15 repetitions, switch sides, crossing left leg over right knee and trying to touch the right elbow to the left knee.
Too much stomach work can hurt your back, however. "There has to be a balance between the abdominals and the extensors of the spine," says Dr. Silberstein. "In people who overdo sit-ups, the hip flexors get too tight and they lose flexibility in that area. Those tight muscles throw the lower back into [swaybacked] posture."
To maintain muscle balance, Dr. Silberstein recommends stretching the muscle that runs from the front of the hip to the knee: Lie on your abdomen, bend your knees, and try to touch your feet to your buttocks.
And for the extensors of the back, he advises: Lie prone, with a pillow or two under your stomach, and your arms and legs extended in a straight line. Lift one arm and the opposite leg simultaneously; hold for a few seconds, relax, and repeat with the other arm and leg.
The Orioles work their low-back muscles, too, using a device called a "Roman chair." Lying prone, with their ankles held by a bolster, the upper body hanging down from the waist and the fingers behind the ears, they have to raise the upper body to a horizontal position.
"This is not a fun exercise," Mr. Johnson said. "It is not one of those that you feel great after. You think, 'Geez, what have I done?' But six to eight weeks down the road, you feel good because you are limber in the lumbar area."