Kinds of Flexibility and the Right Role of Splits in Taekwondo, Karate,
Kurtz, author of Stretching Scientifically and Secrets
This is the fourth installment of my column on training that appeared
in September 1999 issue of TaeKwonDo Times.
Read the previous installment
In previous articles in this column (in TaeKwonDo Times
March 1999, May 1999, and July 1999) you learned how to determine if you
have the potential to do a
side split and a
front split, even before you start your stretching program. In this
article you will learn about kinds of flexibility and the right role for
splits in kicker's training.
There are three kinds of flexibility:
DynamicThe ability to perform dynamic movements within a
full range of motion in the joints. High kicks are a display of dynamic
Static passiveThe ability to assume and maintain extended
positions using your weight (splits), or using strength not coming from
the stretched limbs, such as lifting and holding a leg with your arm or
by other external means.
Static activeThe ability to assume and maintain extended
positions using only the tension of the agonists and synergists while
the antagonists are being stretched. One example is lifting the leg and
keeping it high without any support.
The principles of flexibility training are the same in all sports. Only
the required level of a given kind of flexibility varies from sport to
Flexibility training is speed-specific because in the muscle there are
two kinds of stretch receptors, one detecting the magnitude and speed
of stretching, the other detecting magnitude only. Dynamic stretches improve
dynamic flexibility and static stretches improve mostly static flexibility,
which is why it does not make sense to use static stretches as a warm-up
for dynamic action.
Flexibility training is also joint-specific. One person may have great
flexibility in some joints but not in others, some joints may have great
range of motion in one plane of motion but not in all planes. Finally,
flexibility training is position-specific. If you stretch lying down but
display your flexibility standing up, your range of motion is going to
be worse than if you stretched standing up (Breit 1977).
Dynamic stretching by using movements similar to the taskfor example,
leg raises before kicking, lunges before fencing, arm and racquet swings
before playing tennis, done with gradually increasing range and speed
of motionfacilitates neural pathways that will be used in the task.
(Facilitates means increases the excitability or receptivity of
the neurons involved in the movements because of repetitive use or because
of the accumulation of impulses arriving from other neurons.) These
movements of gradually increasing similarity in range and speed of motion
require muscular contractions increasingly similar to those of the task
(e.g., kick, fencing attack, serve). These contractions cause arterioles
and capillaries in the working muscles to dilate in proportion to the
force of contraction.
Static stretches do not facilitate these neural pathways, do not prepare
the nervous system and blood vessels in the muscles for the dynamic task.
You even sweat differently when warming up with dynamic actions than when
doing static stretches. During dynamic exercises you sweat all over and
your sweat is hot. During static stretching you sweat little, mainly on
the face. This tells you that static stretching, such as attempting splits,
is a poor warm-up. That takes care of the common misconception that sitting
or standing in stretched positions, and attempting to do splits during
a warm-up, improves one's range of motion for kicking. (In a future column
I might address the misconception that static stretching before a workout
prevents injuries.) Static stretches are most effective at the end of
your workout, during cool-down (Stretching Scientifically,
As a kicker, then, why should you be interested in doing a front splita
static stretch nonspecific for kicking that requires static flexibility
while kicks require dynamic flexibility? Because being able to do the
front split facilitates (though it is not necessary for) learning high
side and roundhouse kicksthe position of legs in a front split is
the same as in high side and roundhouse kicks (the rear leg in this split
corresponds to the kicking leg and the front leg to the supporting leg).
If you can do the front split, you can practice the high side and high
roundhouse kicks slowly enough to control and correct your body alignment,
especially of the supporting leg in relation to the kicking leg and of
the trunk in relation to the legs.
and a high roundhouse kick
The side split, if done according to my method of developing flexibility
and strength both at the same time, strengthens muscles of the inner thigh.
These are the muscles of the supporting leg that are stressed when you
do high kicks. During a kick the kicking leg displays only dynamic flexibility
but the stretch on the supporting leg is more like a static stretch, albeit
short. The inner thigh of the supporting leg tenses while being stretched
by the momentum of your whole body moving toward a target. To strengthen
the muscles of the inner thigh you can either tense them in a wide straddle
stance and eventually in a side split or you can do resistance exercises
such as adductor flyes and adductor pulldowns (shown on the video Secrets
In the next column you will learn about the method of developing dynamic
flexibility so you can kick high anytime without any warm-up.
Read the next installment of this column
Breit, N. J. 1977. The effects of body position and stretching
technique on development of hip and back flexibility. Dissertation
for degree of Doctor of Physical Education. Springfield College
Kurtz, T. 1990. Secrets of Stretching: Exercises for the Lower
Body. Island Pond, VT: Stadion Publishing Co. Inc.
Kurtz, T. 1994. Stretching Scientifically: A Guide to Flexibility
Training. Island Pond, VT: Stadion Publishing Co. Inc.