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Got Stretch?
November 21 , 2004 by Mike MasoodFlexibility is defined as the range of motion (ROM) within a joint. A joint itself is limited to the properties and body segments that come together to form its structure. There are many factors that limit joint mobility. Genetics, aging, growth spurts, connective tissue elasticity, strength of opposing muscle groups, tendons, neuromuscular coordination and the joint structure itself all play a role in how the joint functions.
What are the benefits of stretching? Research shows that stretching can improve performance, decrease the risk of injury, improve blood flow, increase the nutrient exchange within muscles, improve coordination, improve balance and reduce muscular tension.
What are the factors that affect flexibility? Age, gender, body temperature and pregnancy are the main factors that affect flexibility. Studies have shown that the greatest increase in flexibility occurs between the ages of seven and twelve. After age twenty five, our connective tissues tend to lose their elasticity. Aging increases the number of collagen fibers and we also lose the ability to keep soft tissue hydrated. Women in general tend to be more flexible then men. One theory is that women, due to childbearing, must have a greater range of motion especially in the pelvic region. Pregnancy causes changes in hormonal levels which affect the laxity of joints. The release of estrogen, relaxin and progesterone allow joints to become more mobile. A warm muscle will have more viscosity then a cold muscle. This basically means that the warmer the muscle the greater the chance of increasing the range of motion.
There are two basic types of flexibility: passive and active. Passive flexibility can best be described as flexibility that involves slow gradual movement through a range of motion. An example would be a gymnast moving into and holding the split position. Passive flexibility can be affected by body temperature, connective tissue elasticity, joint structure and the musculotendonous junction. Active flexibility actually involves rapid movement throughout the joint. Emphasis here is on the ability to maintain speed and force through the range of motion. A gymnast performing a split leap is any example of this type of flexibility. Active flexibility is affected by the same variables as static flexibility and also includes balance, speed and torque.
There are four basic stretching techniques; Static, Dynamic, PNF (Proprioceptive Neuromuscular Facilitation) and AIS (Active Isolated Stretching). Static stretching is a form of passive flexibility which involves a slow sustained movement. It usually incorporates low intensity and a long duration. Dynamic stretching is a form of active flexibility. It incorporates high force and short duration. PNF involves the contract-relax reflex. The purpose of this type of stretching is to confuse the nervous system to allow you to go into a deeper stretch. AIS is the newest technique and was originally used in the rehabilitative setting. AIS incorporates repetitions, mild resistance and never holding the stretch for more then 2 seconds. The key component here is to contract one muscle so the muscle on the other side relaxes which allows it to be stretched.
Over the years I have been frequently asked “what is the best way to stretch?” My response has been “just stretch!” I suggest that you are warmed up as a muscle that is cold won’t stretch as well as one that is warm. You also increase your risk of injury if you are not warmed up. Like training, stretching can be specific for the activity that you are doing. I have found that if you are involved in activities that require explosive movements then you should warm up that way. Perform what you are going to do on the field or court at a lower level. Gradually increase your speed and force of movement until you are ready to go. After the activity, a more passive stretch can be used to help relax the body.
When you are designing your stretching program keep the following in mind: an elevated tissue temperature will help increase your range of motion, connective tissue elongation is the main objective, intensity and duration of the stretch are specific to the type of stretching and maintaining proper body alignment to maximize the efficiency of the stretch.
