Tips for the Stretching Exercise to get a Healthy Body
Muscles must contract for movement to occur. The contracting muscles are called agonists and are the prime movers. For an agonist to contract, shorten, and produce movement, a reciprocal lengthening of its antagonists must occur. For example, when the biceps muscle of the upper arm contracts, its opposite, the triceps muscle, must relax and lengthen. In this case the biceps is the agonist and the triceps is the antagonist. The triceps becomes the agonist for movements that require it to contract, in which case the biceps becomes the antagonist. Understanding these concepts is necessary to understand stretching techniques.Ballistic stretching uses dynamic movements to stretch muscles. Each time a muscle is stretched in this manner, the myotatic reflex (stretch reflex) located in that muscle is also stretched. It responds by sending a volley of signals to the central nervous system that order the muscle to contract, thus resisting the stretch. This is not only counterproductive-the muscle is forced to pull against itself-but can lead to injury because the elastic limits of the muscle may be exceeded. Ballistic stretching is not recommended for flexibility development.
Static stretching involves slowly moving to desired positions that are held for 15 to 30 seconds and are then slowly released. This method of stretching does not activate the stretch reflex (automatic or reflexive contraction of a muscle being stretched), so the muscle is essentially stretched without opposition. These positions should produce a feeling of mild discomfort but not pain. Static stretching results in little or no muscle soreness, has a low incidence of injury, and requires little energy.
These guidelines should be followed for safe and effective stretching -
- Warm-up for a few minutes before stretching by walking, slow jogging, and light calisthenics.
- Stretch to the point of discomfort.
- Do not stretch to the point of pain.
- Hold each stretch for 15 to 30 seconds.
- Move slowly from position to position.
- Perform each stretch at least twice.
- Stretch after the workout; this may actually produce the greatest benefit because the muscles are warm and more amenable to stretching.
- Perform stretching exercises daily if possible.
- Proprioceptive neuromuscular facilitation (PNF) is another effective and acceptable stretching technique. It is more complex than most methods of stretching, but it is the most effective. By combining slow passive movements (the force for passive movement is supplied by a partner) with maximal voluntary isometric contractions, you can bypass the myotatic reflex stimulation that accompanies changes in muscle and tendon length.
- All variations of PNF stretching require a partner and some combination of passive stretching and isometric contractions. Two of the common PNF methods, contract-relax (CR) and slow-reversal-hold-relax (SRHR) are presented. For comparison, both figures exemplify stretching the hamstring group (muscles in the back of the thigh). The hamstrings are the antagonist muscle group, and the quadriceps muscles (muscles in the front of the thigh) are the agonists. For example, the CR method is performed as follows.
- A partner gently pushes the upraised leg in the direction of arrow A. This movement passively stretches the antagonist (hamstrings).
- The subject follows this with a 6-second submaximal contraction of the agonist (quadriceps).
- This is followed by another passive stretch of the hamstrings.
This is repeated twice with a few seconds of rest between sequences.
- The SRHR method is performed in the following manner:
- A partner gently pushes the upraised leg in the direction of arrow A.
- The subject then performs a 6-second maximal voluntary isometric contraction (MVIC) of the antagonists (hamstrings) against resistance supplied by the partner.
- The subject follows this with a 6-second submaximal contraction of the agonists (quadriceps).
- This is followed by another passive stretch of the hamstrings.
- This sequence is repeated twice with a few seconds of rest between exercises.
Although PNF appears to be the most effective stretching method for enhancing flexibility, it has some limitations. It requires a partner, it produces more pain and muscle stiffness, it requires more time, and the risk of injury is increased, particularly when novices use this technique.
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