抄録
An increase or decrease of the hammer head mechanical energy was caused by an accumulation of the positive or negative handle power which was the product of wire tensile force and handle velocity in the wire length direction. During single support phase a decrease of the wire tensile force was reduced by a fictitious force caused by handle relative pulling acceleration and relative leading velocity to thrower's center of mass (C.M.). Ground reaction force was resulted from maintaining balance with wire tensile force, hammer head centrifugal force, hammer handle coriolis force, and so on under rotational coordinate system. During double support phase handle relative pushing acceleration and relative drawing velocity to thrower's C.M. caused a fictitious force which make balance with the addition of wire tensile force and hammer head rotational force in the wire length direction and with hammer head rotational force in the horizontal direction perpendicular to wire, so that thrower pushed the ground on his/her feet.
