Tuesday, November 15, 2005

Static Stretching and Isometric Stretching

Static stretching is different from passive stretching. Static stretching consists of stretching a muscle or group of musclesto its farthest point and then maintaining or holding that position. Passive stretching consists of a relaxed person who is relaxed while some external force such as a person, apparatus, wall or other, brings the joint through its range of motion.

Isometric stretching is a type of static stretching which involves the resistance of muscle groups through isometric contractions or tensing of the stretched muscles. This increases static-passive flexibility and is much more effective than either passive stretching or active stretching alone. It also helps to develop strength in the "tensed" muscles, which in turn helps to develop static-active flexibility, and it seems to decrease the amount of pain usually associated with stretching. Resistance can be applied manually to one's own limbs, a partner can apply the resistance, or an apparatus such as a wall or the floor can provide resistance.
Examples manual resistance are holding onto the toes of your foot to keep it from flexing, or putting you leg high on the wall and pressing against the wall, making sure you do not lower your leg. Or a partner could hold your leg up high.
Isometric stretching is an intermediate to advanced movement, and is not recommended for children and adolescents whose bones are still growing, or for people with high blood pressure and osteoporosis. Another type of stretch or warm-up should be done before isometric stretching. Isometric stretching can look easy, but can be strainful and can have your hear rate go up. Do this type of stretching if you have been cleared by a physician and are fit. Also, do not do isometric stretches every day. They are too be done a few times a week, month or year, depending on your fitness level and goals. If you do these stretches one day, wait at least two days before you do them again.

To perform an isometric stretch, assume the position of a passive stretch for the desired muscle. The stretched muscle should be stretched for 7-15 seconds. Then, relax the muscle for at least 20 seconds.
When you stretch, some muscle fibers are resting. During an isometric contraction, some of these resting fibers are being pulled upon from both ends by the muscles that are contracting, and they stretch! If you are only performing an isometric stretch, not many muscle fibers contract. But if you are already stretching a muscle, the initial passive stretch overcomes the stretch reflex if you hold the stretch long enough. When you subject it to an isometric contraction, some resting fibers contract and some resting fibers would stretch. Many of the fibers already stretching may be prevented from contracting by the inverse myotatic reflex (the lengthening reaction) and would stretch even more. When the isometric contraction is completed, the contracting fibers return to their resting length but the stretched fibers would remember their stretched length and will retain the ability to elongate past their previous limit for a period of time. The muscle spindles habituate to an even further-lengthened position.

Some medical studies show that a certain type of stretching for certain periods of time does not always make a difference in health, flexibility, prevention of injury and circulation. Everyone’s body is different. Try out warm-up and cool-down stretches for yourself. Getting to know your body is key. See the difference each type of stretch makes at different part of your work out. And vary your stretches throughout the year according to how you feel and results. For medical journal articles, see www.pubmed.gov, which gives free access to Medline, the largest database of medical journals, probably in the world!

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Some information for this blog was obtained from http://www.cmcrossroads.com/bradapp/docs/rec/stretching/stretching_4.html
Accessed on November 14, 2005

Disclaimer: Information on this blog is posted for information purposes, not as a substitute for professional medical advice.

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