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force-velocity relationship in overarm throwing was determined using
ball weights varying from 0.2 to 0.8 kg. Seven experienced handball
players were filmed at 240 frames per second. Velocity of joints of
the upper extremity and ball together with the force on the ball were
derived from the data. A statistically significant negative relationship
between force and maximal ball velocity, as well as between ball weight
and maximal ball velocity was observed. Also, with increase of ball
weight the total throwing movement time increased. No significant
change in relative timing of the different joints was demonstrated,
suggesting that the subjects did not change their "global"
coordination pattern (kinematics) within the tested range of ball
weights. A simple model revealed that 67% of ball velocity at ball
release was explained by the summation of effects from the velocity
of elbow extension and internal rotation of the shoulder. With regard
to the upper extremity the internal rotation of the shoulder and elbow
extension are two important contributors to the total ball velocity
at release.
KEY
WORDS: Kinematics, handball, ball weight, proximal distal sequence.
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