| Four
black belt throwers (tori) and one black belt faller (uke) were filmed
and analyzed in three-dimensions using two video cameras (JVC 60 Hz)
and motion analysis software. Average linear momentum in the anteroposterior
(x), vertical (y), and mediolateral (z) directions and average resultant
impulse of uke's center of mass (COM) were investigated for three
different throwing techniques; harai-goshi (hip throw), seoi-nage
(hand throw), and osoto-gari (leg throw). Each throw was broken down
into three main phases; kuzushi (balance breaking), tsukuri (fit-in),
and kake (throw). For the harai-goshi and osoto-gari throws, impulse
measurements were the largest within kuzushi and tsukuri phases (where
collision between tori and uke predominantly occurs). Both throws
indicated an importance for tori to create large momentum prior to
contact with uke. The seoi-nage throw demonstrated the lowest impulse
and maintained forward momentum on the body of uke throughout the
entire throw. The harai-goshi and osoto-gari are considered power
throws well-suited for large and strong judo players. The seoi-nage
throw is considered more technical and is considered well-suited for
shorter players with good agility. A form of resistance by uke was
found during the kuzushi phase for all throws. The resistance which
can be initiated by tori's push or pull allows for the tsukuri phase
to occur properly by freezing uke for a good fit-in. Strategies for
initiating an effective resistance include initiating movement of
uke so that their COM is shifted to their left (for right handed throw)
by incorporating an instantaneous "snap pull" with the pulling
hand during kuzushi to create an opposite movement from uke.
KEY
WORDS: Biomechanics, impulse, kinematics, martial art, momentum,
collision.
|
