The role of sports and physical activity
has become more and more popular in some developed countries. Trainers and
athletes are becoming more concerned with prevention and sports injuries than
ever. Muscular injuries are the most commonly occurred in sports that required bursts
of speed and rapid acceleration and deceleration, such as rugby, football and sprinting
events, and are the major causes of lost time from the sporting activities. Sports
therapist found that hamstring muscle strain is a common injury among sports.
There are many proposed etiologies for hamstring muscle group injuries:
(1) Strength imbalance
(2) Lack of flexibility exercises
(3) Muscle fatigue and
(4) Inadequate warm up before exercise.
Since sport injury is multifactorial, we
could pay more attentions to the activities between the flexibility of the
muscles and the other measurable performance factors.
Muscle stretching has long been
considered a major component in the prevention and rehabilitation of sports
injuries in warm up period. In the past, much of the investigation focused on
the most effective hamstring muscle group stretching method. Ballistic stretching, static stretching and proprioceptive neuromuscular facilitation (PNF)
are presently used to improve flexibility.
But, the ballistic technique is performed with a bouncing movement and
will reflexively cause a protective muscle contraction of the activated
muscles. Thus, stretching a muscle against muscle contraction would increase
the chance of injury to the muscle and tendons.
Muscle flexibility and isokinetic strength are very
important to athletes, more effort and training should be put to enhance their
athletic performance. Some sports therapy focus on the relationship between
hamstring muscle flexibility, rate of injury and the most effective hamstring
stretching method. They support the fact that stretching provides a good mean
to increase the muscle flexibility. A great deal of variability exists,
however, concerning which type of stretching technique is the most effective
method.
The sports therapist suggested that both
the static stretching and the proprioceptive neuromuscular facilitation (PNF)
can increase the hamstring muscle flexibility and the isokinetic peak torque
after a 3-week training. Increases in hamstring muscle flexibility range from
26.5 % for the static stretching group to 30 % for proprioceptive neuromuscular
facilitation group.
Hamstring muscle length is only one of
many factors, which can affect hip flexion and knee extension during the
assessment and stretching training. Other limiting factors and psychological
reaction toward muscle stretching cannot be eliminated. It is concluded that the static stretching exercises
and the proprioceptive neuromuscular facilitation may be effective technique
for increasing the hamstring muscle flexibility and the hamstring isokinetic
peak torque in the open kinetic chain.
