Is it a strain to reach the top shelf or bend over to tie your shoes? If so, some flexibility training might be in order. The answer to tight, stiff muscles is careful stretching. Stretching can make you feel better and able to do more things, and can help prevent injury to muscles.

"People who lack flexibility may be unnecessarily exposing themselves to an injury," according to Leslie Williams, P.T., division director of Spectrum Rehabilitation. Even if you’ve felt stiff for quite a while, you can regain flexibility. Older people who regularly stretch can be as flexible as younger people.

Basic stretches should focus on the body’s major muscle groups. Important parts to stretch include the muscles of the calf, thigh, hip, lower back, neck, and shoulders. If you routinely use certain other parts of your body, stretch these as well.

Here are a few good exercises to begin with:

• Lower-back stretch: Lie on a firm surface. Gently pull your knee toward your shoulder and hold it.
• Quadriceps stretch: Stand facing a wall with one hand on the wall. Bend one knee backward and grab your foot with your other hand. Gently pull the heel toward your buttocks until you feel a stretch in the front of your thigh.
• Shoulder stretch: Move your hand across your upper body and grab the shoulder so that you feel the back of your shoulder stretch.

Keep these tips in mind when stretching:

• Contrary to what you may have heard before, it's better to stretch AFTER rather than before exercising. But DO warm up before a workout by doing a simple exercise at low intensity for five minutes, such as walking. If time allows, you will get most benefit by stretching before AND after your workout.
• Don’t bounce or lock your joints. Slowly stretch into the desired position and hold it for 30 seconds. "The most effective stretch is a long, slow and gentle stretch," Ms. Williams cautioned.
• Relax and breathe deeply while you stretch.

Stretching may not be advised if you have certain types of injuries. Ask your doctor or physical therapist first. Most people, even with conditions such as arthritis, can indeed maintain a stretching program that will help them feel limber, younger, and more fit.