Bear-cave crunches.

If you hear crunches from a bear cave, should you run? Nah; the bear might just be doing sit-ups. Scientists are learning that bears make very good use of their hibernating time. Instead of caving in to the winter blahs, these big bruins actually exercise--in their sleep!

"When bears emerge from the den in the spring, they're in good shape," says Wayne Kasworm, a wildlife biologist for the U.S. Fish and Wildlife Service. Instead of getting fat and losing muscle tone over the cold, idle months of winter--like some people--bears manage to stay sharp, fit, and ready for action.

Are they really doing exercises like abdominal crunches? No, but what they do is almost as good.

Can you exercise in your sleep? Probably not; you might fall out of bed. But try these exercises when you are awake to stay sharp and ferocious just like the bears.

BEAR SCRATCH

Scratch your bear back this way: Lean back against a smooth wall, then slowly bend your knees so your back slides down along the wall. Stop when your upper legs are parallel to the floor, then straighten your legs again to stand up. This is great for itchy backs and for building strong thigh muscles.

BUILDING BEAR TOES

Exercise your calf (lower leg) muscles this way: Stand with your toes on a step or raised surface. Slowly lower your heels and then come up on tip-toes to reach the best morsels of bear food up high in the trees.

BEAR GRIP

Squeeze a small rubber or soft ball with your paws to increase your grip and grab strength.

BEAR IN MIND:

All exercises should be done in moderation: That means don't make your muscles hurt or injure yourself. Let your body tell you how many to do, then slowly build up so you can do more. Take your time!