How flexible are you? If you're unsure, just try leaning over and touching your toes. As a physican and martial arts practitioner, I see the good and bad effects of stretching. There are many good reasons to stretch, especially for those who want to age gracefully, because improving physical condition inside the body also shows on the outside. As we age, our muscles tighten and range of motion in the joints can decrease. This can put a damper on active lifestyles and even hinder day-to-day, normal movements. Stretching can help improve flexibility. Better flexibility may improve your performance in physical activities or decrease your risk of injuries by helping your joints move through their full range of motion. Many people don't know that muscle type influences flexibility.
I've noticed throughout my years of medical training and practice that most people pay more attention to stretching their legs and hamstrings than to any other muscle group. You might try on rare occasions to stretch your biceps, chest muscles or shoulders, but I'm willing to wager that, like most people, you spend more time stretching your legs, if you stretch at all. The attention to legs and hamstrings isn't surprising, since sitting in chairs -- which we tend to do for too many hours -- shortens and stiffens the muscles in your legs.
Many people want to be able to touch their toes, and it's a good instinct. Medically speaking, if you're suffering from back pain, being able to bring your legs up to a 90-degree angle when you're lying down is a signal that you're in pretty good shape regarding flexibility. Your nerves and muscles are most likely fine. If you happen to be unable to stretch your legs up to 90 degrees, your caregivers may take it as a sign that more diagnosis may be necessary.
To put it somewhat simplistically, there are generally two types of people with regards to flexibility -- those who have it and those who don't, and muscle type has a lot to do with it.
If you lack flexibility
There may be many reasons for this, but the most common cause is short, wide muscles. Those with this muscle type who are not as limber as others have their work cut out for them, but tight muscles feel much better after moderate stretching. Reduced muscle tension that results from stretching improves range of joint movement and muscle coordination, and increases blood circulation that produces higher energy levels. People in this group have to consistently stretch to prevent the physiologic loss of flexibility that comes with age. The more frequently you stretch, the more quickly you will gain flexibility, though big changes take time. After every exercise session, try to stretch your arms, your back from the base of your neck to the top of your sacrum and your legs from toes to hips. If you don't exercise, stretch at least three or four times a week. Do each stretch to the point of "mild discomfort," and hold each stretch for 10-30 seconds.
If you are flexible or hyperflexible
You might have long, thin muscles or just be a naturally flexible person. Generally maintaining appropriate flexibility and range of motion in joints is good for people of any muscle type. However, those who fall into this category need to be extra vigilant. Over-stretching can cause muscle and/or tendon strain, most commonly in the neck, shoulder, hips, legs and back. Less commonly, subluxation/dislocation of joints can occur. For those who are extremely flexible, over-stretching is a huge temptation. You sometimes may want to push beyond what you can do. You will have to use reason and common sense. If you feel pain, damage may already have been done.
The rules of stretching are basic. If it hurts, you've gone too far. Everyone who stretches should be careful not to stretch to the point of even moderate pain. Be careful not to stretch a muscle beyond its natural range, which you can see and feel. Breathe while stretching, so as not to deprive your muscles of the oxygen they need -- never bounce.
Medicines
Use extra caution when stretching and participating in sports if you are taking certain medications. Muscle relaxants may enable you to go too far or dull your perception of pain. Antibiotics such as Cipro or Levaquin are associated with tendon weakening and rupture.