Stretching
Passive stretching
     - While the athlete is relaxed, an exteranl force, applied either manually or mechanically, lengthens the shortened tissues.
Active Stretching
   - The athlete participates in the stretching maneuver to inhibit tonous in a tight muscle.
Flexibility exercises
    - The terms stretching and flexibility exercises are often used interchangeably.

Ballistic Stretching
   - A bouncing movement in which repetitive contractions of the agonist muscle are used to produce quick
     stretches of the antagonist muscle.
   *If the forces generated by the jerks are greater (twice much as static one) than the tissues' extensibility,
      muscle injury may result.
    ... So, We DO NOT use this method for the athletes at early stage of warming up. But you can do this
        stretching for late stage of warm-up because muscles have to ready for bouncing mortion thorugh
        activities.

Static Stretching
   - Passively stretching a given antagonist muscle by placing it in a maximal stretch and holding it there.
   * 30 ~ 60 seconds (3 ~ 4 times)

PNF Stretching Techniques
   - Combinations of alternating contractions and streches.
      Hold-relax (5~6 seconds 3 times) - end-range isometric contraction of the tight muscle before it is
                                                        passively lengthend.
      Contract-relax -  After the tight muscle has been passively lengthened, concentric isotonic contraction of
                              the tight muscle against resistance before the muscle is elongated.
      Hold-relax with agonist contraction - Prestretch isometric contraction of the tight muscle and relaxation of
                                                          the tight muscle follwed by a concentric contraction of the muscle
                                                          opposite the itght muscle. As the agonist muscleopposite the tight
                                                          muscle shortens, the tight muscle lengthens. This technique
                                                          combines autogenic inhibitaion and reciprocal inhibitation to lengthen
                                                          a tight muscle.
     Agonist contraction - Dynamic contraction of muscle opposite the tight muscle against resistance. This
                                    cause a reciprocal inhibitation of the tight muscle, and the tight muscle lengthens
                                    more easily as the extremity moves.
     Rhythmic Stabilization - Alternating isometric contractions against resistance, no motion intended.

- When soft tissue is stretched, either elastic or plastic changes occur.
   Elasticity is the ability of soft tissue to return to its resting length after passive stretch.
   Plasticity is the tendency of soft tissue to assume a new and greater length after the stretch force has been
   removed. Both contractile and noncontractile tissues have elastic and plastic qualities.
- Muscle strength can also be altered when soft tissue adaptively shortens over time. As muscle losses its
  normal flexibility, a change in the length-tension relationship of the muscle also occurs. As the muscle
  shortens, it no longer is capable of producing peak tension, and tight weakness develops. Loss of flebility,
  for whatever reason, can also cause pain arising from muscle, connective tissue, or periosteum. This, in
  turn, also decreases muscle strength.       
Oh, look at this guy!! His elbow is rotated amasingly!! This hyper-flexibility prevent the elbow injuries. If his elbow were rigid, wouldn't the elbow endure the stress of fast pitching? Probably not... What do you think?