|
Many people are unaware of the fact that there are different types of flexibility. These different types of flexibility are grouped according to the various types of activities involved in athletic training. The ones which involve motion are called "dynamic" and the ones which do not are called "static". The different types of flexibility (according to Tom Kurz, an expert in the field) are:
"dynamic flexibility"
Dynamic flexibility (also called "kinetic flexibility") is the ability to perform dynamic (or kinetic) movements of the muscles to bring a limb through its full range of motion in the joints.
"static-active flexibility"
Static-active flexibility (also called "active flexibility") is the ability to assume and maintain extended positions using only the tension of the agonists and synergists while the antagonists are being stretched. For example, lifting the leg and keeping it high without any external support (other than from your own leg muscles).
"static-passive flexibility"
Static-passive flexibility (also called "passive flexibility") is the ability to assume extended positions and then maintain them using only your weight, the support of your limbs, or some other apparatus (such as a chair or a barre). Note that the ability to maintain the position does not come solely from your muscles, as it does with static-active flexibility. Being able to perform the splits is an example of static-passive flexibility.
Research has shown that active flexibility is more closely related to the level of sports achievement than is passive flexibility. Active flexibility is harder to develop than passive flexibility (which is what most people think of as "flexibility"); not only does active flexibility require passive flexibility in order to assume an initial extended position, it also requires muscle strength to be able to hold and maintain that position.
Factors Limiting Flexibility
According to Gummerson (another expert), flexibility (he uses the term "mobility") is affected by the following factors:
Internal influences
- the type of joint (some joints simply aren't meant to be flexible)
- the internal resistance within a joint
- bony structures which limit movement
- the elasticity of muscle tissue (muscle tissue that is scarred due to a previous injury is not very elastic)
- the elasticity of tendons and ligaments (ligaments do not stretch much and tendons should not stretch at all)
- the elasticity of skin (skin actually has some degree of elasticity, but not much)
- the ability of a muscle to relax and contract to achieve the greatest range of movement
- the temperature of the joint and associated tissues (joints and muscles offer better flexibility at body temperatures that are 1 to 2 degrees higher than normal)
External influences
- the temperature of the place where one is training (a warmer temperature is more conducive to increased flexibility) - the time of day (most people are more flexible in the afternoon than in the morning, peaking from about 2:30pm-4pm)
- the stage in the recovery process of a joint (or muscle) after injury (injured joints and muscles will usually offer a lesser degree of flexibility than healthy ones)
- age (pre-adolescents are generally more flexible than adults) - gender (females are generally more flexible than males) - one's ability to perform a particular exercise (practice makes perfect)
- one's commitment to achieving flexibility
- the restrictions of any clothing or equipment
Some sources also the suggest that water is an important dietary element with regard to flexibility. Increased water intake is believed to contribute to increased mobility, as well as increased total body relaxation.
Rather than discuss each of these factors in significant detail as Gummerson does, I will attempt to focus on some of the more common factors which limit one's flexibility. According to `SynerStretch', the most common factors are: bone structure, muscle mass, excess fatty tissue, and connective tissue (and, of course, physical injury or disability).
Depending on the type of joint involved and its present condition (is it healthy?), the bone structure of a particular joint places very noticeable limits on flexibility. This is a common way in which age can be a factor limiting flexibility since older joints tend not to be as healthy as younger ones.
Muscle mass can be a factor when the muscle is so heavily developed that it interferes with the ability to take the adjacent joints through their complete range of motion (for example, large hamstrings limit the ability to fully bend the knees). Excess fatty tissue imposes a similar restriction.
The majority of "flexibility" work should involve performing exercises designed to reduce the internal resistance offered by soft connective tissues. Most stretching exercises attempt to accomplish this goal and can be performed by almost anyone, regardless of age or gender.
Overflexibility
It is possible for the muscles of a joint to become too flexible. According to `SynerStretch', there is a tradeoff between flexibility and stability. As you get "looser" or more limber in a particular joint, less support is given to the joint by its surrounding muscles. Excessive flexibility can be just as bad as not enough because both increase your risk of injury. Once a muscle has reached its absolute maximum length, attempting to stretch the muscle further only serves to stretch the ligaments and put undue stress upon the tendons (two things that you do not want to stretch). Ligaments will tear when stretched more than 6% of their normal length. Tendons are not even supposed to be able to lengthen. Even when stretched ligaments and tendons do not tear, loose joints and/or a decrease in the joint's stability can occur (thus vastly increasing your risk of injury). Once you have achieved the desired level of flexibility for a muscle or set of muscles and have maintained that level for a solid week, you should discontinue any isometric or PNF stretching of that muscle until some of its flexibility is lost.
|
