Flexibility

Introduction

Flexibility is recognized as an important component of physical fitness. Like other components of fitness, flexibility is more important for some sports than others. For example, long distance runners tend to be relatively inflexible because the activity of running does not require large deviations in joint motion. However, sprinters, and especially hurdlers, require excessive hip motion for the sprinting stride and to clear the hurdles in stride. Subsequently sprinters are required to be relatively flexible in the hip region. Not only are flexibility requirements sports-specific but they can also be joint- specific. In general, athletes must have sufficient musculoskeletal flexibility to meet the demands of the sport, otherwise performance will be sub-optimal and the risk of injury will be increased.

Definition and Measurement

Flexibility can be measured using static or dynamic tests that involve either passive or active motion. Flexibility is typically understood to refer to the maximum available range of motion in a joint or series of joints. For example, the passive straight leg raise test measures hip flexion range of motion with the knee extended, and is though to reflect hamstring flexibility. This is a measure of static flexibility, measured passively. Field tests of flexibility generally involve passive static measures. However, tests of maximum active motion, such as the sit and reach test, are also commonly used. More recently there has been increased interest in the measurements of dynamic flexibility whereby the passive or active stiffness of muscle is quantified. While these measurements are thought to better reflect the functional significance of flexibility the measurement techniques are not conducive to testing large populations.

While the term flexibility is generally thought to refer to the extensibility of muscles, the measurements are also affected by ligamentous laxity or joint looseness. The most flexible athletes also tend to have ligamentous laxity. For example, gymnasts are more flexible than soccer players on most standard flexibility tests and a higher number of gymnasts will have ligamentous laxity than soccer players.

Developing Flexibility

An individual’s flexibility is an inherent attribute with some potential for adaptation to habitual activity or with flexibility training. Flexibility training refers to the practice of stretching. There any many approaches to stretching musculoskeletal tissues but typically stretching practices involve some type of static or ballistic stretches. Static stretches are thought to be safer because they involve a slow passive stretch to the targeted muscle. The muscle is held in a stretched position for a time period usually varying from 10-60 sec and this is repeated two-to-six times. Ballistic stretches are cyclic active movements intended to repeatedly stretch and release the target muscle group without a hold period. Five to ten repetitions or cyclic movements for up to 60 sec are typical. There is some injury risk with ballistic stretching if the movement velocity is high.

Regardless of the type of stretch that is utilized, it is essential that the stretch sufficiently stresses the target muscle or joints in order to induce an adaptation. However, it is also important to avoid causing an injury by overstressing the target area. Therefore, the recommendation is to stretch to the point of mild discomfort but not to the point of pain. One of the first adaptations to a stretching program is an increased tolerance of stretch, whereby the perceived discomfort decreases for a given degree of stretch. This allows for an increase in joint range of motion. For long-term improvements in flexibility, stretching should be performed at least every other day for a minimum of six weeks. However, soon after training discontinues the gains in flexibility will start to reverse.

Flexibility and Injury Risk

The flexibility concerns of the athlete should be twofold: 1) Do you have sufficient specific flexibility to adequately perform the activities required of your sport? 2) Is your overall flexibility sufficient so as not to place you at increased risk for injury? Too often, the emphasis is on overall flexibility rather than addressing the specific flexibility requirements of a given sport. The association between flexibility and injury risk is often overstated and interpreted simplistically. The inflexibile or “tight” athlete may not be at increase risk for injury. It is probably those athletes at either extreme of the flexibility continuum that may be at increased risk. The key is to determine the flexibility patterns typical for individuals in a given sport, and assess the athletes with inadequate flexibility can be encouraged to work on improving their flexibility by emphasizing that it is not within the accepted standards for their sport.

Warm-up and stretching prior to a sports activity are thought to protect against injury and prepare the athlete to adequately perform the given activity. It is important to consider warm-up and stretching prior to activity as distinct from flexibility. Flexibility is largely an inherent or intrinsic attribute while pre-activity warm-up and stretching are practices that the athletes chooses to perform (extrinsic factors). Warm-up and stretching are as important to the flexible athlete as the inflexible athlete. Warm-up by lightly exercising the major muscle groups to be used in the given activity has the same effect as stretching. Both activities decrease the passive tension in the muscles thereby increasing available joint motion.

Flexibility and Aging

Flexibility is known to decrease with age and the older athlete often complains of increased stiffness when tying to perform habitual sporting activities. The loss of flexibility parallels the age-associated strength loss. The primary flexibility problem is that the functional range within which the muscles operate decreases as one gets older. Surprisingly, the muscle stiffness with this functional range is not significantly increased. The muscles are simply shorter and subsequently lose their ability to operate effectively at the extremes of motion. Although flexibility exercises are useful in improving mobility, maintaining muscle strength throughout the range of motion is probably more important for the elderly.

Summary

Athletes must have sufficient flexibility to meet the demands of their sport, otherwise performance will be impaired and there may be increased risk for injury. Flexibility patters are specific to given sports and are typically quantified using static tests of maximum range of motion. Stretching techniques involving constant stretches or cyclic stretches are used to improve flexibility in the long term and are also used as part of pre-activity warm-up.

This is provided for general information. It does not purport to encompass all risks associated with flexibility training, nor is it a substitute for your own good judgment.

Expert Consultant: Stephen J. Nicholas, MD From http://www.sportsmed.com

Article courtesy of ARA Content
http://www.aracontent.com/

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