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1
BIOMECHANICS OF THE KARATE FRONT-KICK D. Gordon
E. Robertson, Carlos Fernando, Michael Hart and
François Beaulieu School of Human Kinetics,
University of Ottawa, Ontario, CANADA, K1N 6N5
Introduction The front-kick (mae geri) in karate
is one of the strongest and most easily mastered
kicks. This project examined the powers produced
by the lower extremity joints of the kicking leg
of two elite (fourth dan) martial artists
performing both closed and open stance
front-kicks.
Results The moments and powers of the ankle were
insignificant and are not reported. The angular
velocities, net moments of force and the powers
produced at the knee and hip for a typical open
stance kick appear in Figure 2. Two arrows
indicate when the foot left the ground and when
it contacted the pad.
Discussion The powers produced by the open stance
kicks, as expected, always produced larger
moments and powers than the closed stance kicks.
Obviously, the added range of motion and greater
pre-stretch enabled the subjects to generate
greater impulses and foot velocities.   The
sequencing of the moments were consistent across
all trials and both subjects. The motion began
with almost simultaneous flexing of the hip and
knee joints. The hip flexors were responsible for
flexing both joints as shown by the burst of
positive work done by the hip flexors while the
knee moment of force was relatively
unproductive. After the hip reached maximum
flexion velocity, the hip moment of force became
extensor (presumably due to eccentric contraction
of the gluteals) causing the hip to slow its
flexion and initiate knee extension (whip
action). Not surprisingly, based on similar
research on the mechanics of soccer kicking
(Roberson Mosher, 1985) and sprinting (Lemaire
Robertson, 1989) the knee extensor moments did
not contribute to knee extension. Instead, the
knee moment was flexor producing negative
(eccentric) work to presumably protect the knee
from hyperextension at the end of the kick.
Purpose The purpose was to determine the
contributions and sequencing of the ankle, knee
and hip moments during the Karate front-kick (mae
geri).
Methods Two subjects with fourth Dan levels
(black belts) were videotaped while kicking from
both open (feet apart) and closed (feet together)
stances at a kicking pad. The subjects performed
five kicks each with the support leg on a force
platform. Reflective markers were only placed on
the kicking leg. Inverse dynamics was used to
compute the net moments and their powers produced
at the ankle, knee and hip. Figure 1 shows the
experimental setup and a stick-figure and profile
representation of a typical open-stance kick.
References Lemaire ED,Robertson DGE (1989) Track
Field J, 3513-17. Park, YJ (1989) A
biomechanical analysis of Taekwondo front-kicks,
Unpublished Ph.D. dissertation, U.
Minnesota. Robertson DGE, Mosher RE (1985)
Biomechanics IX-B, 533-538 Robertson DGE (2002)
Biomech Motion Analysis System,
http//www.health.uottawa.ca/biomech/-software. S
orensen H, Zacho M, Simonsen EB, Dyhre-Poulsen P,
Klausen K (1996) J Sports Sci, 14483-495.
Figure 2. Typical angular velocities (top),
moments of force (middle) and moment powers
(bottom) of the knee and hip moments during an
open stance karate front-kick. Left arrow
indicates lifting of kicking leg right arrow is
contact. Positive angular velocities and moments
of the knee are flexor positive angular
velocities and moments of the hip are extensor.
Figure 1. Stick-figure and profiles of
closed-stance front-kick
Biomechanics Laboratory