Welcome to Crew and A, an occasional feature where we will tackle your fitness questions with the same melange of brilliance, wit and shrewd deference to outside experts that sets us apart from other fitness columns clamoring for your attention.

I have recently taken up walking and have built up my distance to 10,000 steps, which I usually complete in about 80 to 90 minutes. I develop shin splints after about 40 minutes. Am I overdoing this?

-- Raju Lathigra, Germantown

With the possible exception of blisters, shin splints are the most common malady facing beginning walkers, says Jim Rippe, author of numerous fitness books, including "The Complete Book of Fitness Walking" (Simon & Schuster).

"That muscle in the front of the leg is the anterior tibialis and its sole function is to brake the foot" -- i.e., to slow your forward motion, Rippe explains. Your pain is likely caused by inflammation of the tendons that connect to the anterior tibialis. Because that muscle is small, it doesn't take much stress to cause inflammation. And because of the muscle's limited function, there is little you can do besides running and walking to strengthen it.

Shin splints are common among "people who ramp up their distance or speed too quickly," Rippe says. "The brake has to work harder" and gets overused, resulting in the painful inflammation. Rest until the pain subsides, then return to walking at reduced speed or distance. Ramp back up slowly; if you experience pain, take an anti-inflammatory and ice your shins.

You can reduce impact by walking on softer surfaces such as grass, and by wearing well-padded walking shoes. You can also try something other than walking: "Aerobic exercise that does not strain the tendon includes cycling, swimming, elliptical machines and stair-steppers that accommodate your whole foot (not just the ball)," Rippe says. "Let your body guide you. If it hurts, rest it."

Can flexibility be increased after one's thirties? How regularly must you stretch before you should expect to notice a difference?

-- Rebecca Adams, Hyattsville

Flexibility can be increased somewhat, but how much depends largely on your body type, says stretching expert Bob Anderson, author of "Stretching" (Shelter Publications).

"Most people will lose flexibility over time," Anderson says, mainly due to sedentary behavior, which tightens the back of the body: lower and upper back, hamstrings, calves and neck. "The most realistic goal for most people is to keep what flexibility you have . . . [and] maybe gain back what you've lost over time."

To test your flexibility, sit straight-legged on the floor and reach for your toes. Notice where your fingertips reach. You can gauge improvements over time by your progress in this stretch, Anderson says.

Anderson cautions against over-stretching, especially at the beginning, mainly because people "will not like it and will quit," he said. "Don't worry about how flexible you are. Just learn to stretch properly; you will naturally limber up. How flexible you are has nothing to do with whether you are doing it right."

In addition to Anderson's book, stretching videos can be a good source of instruction. Briefly: Warm up with a few minutes of light aerobic exercise; don't bounce; don't reach beyond the point where you feel a slight pull; and try to keep your body relaxed rather than strained.

Any stretching is better than none, but stretching major muscles at least three times weekly is ideal, Anderson says. Once you learn proper technique, you can do it even while watching TV. If you have trouble motivating yourself, Anderson suggests taking a yoga or stretching class.

Staying hydrated is crucial to flexibility, he adds. Without enough water, tissues lose pliability. Drink water regularly and remember: Clear urine is good; dark yellow is bad.

Have a question for Crew and A? Send it to move@washpost.com.

-- John Briley