抄録
The mechanism of hammer head acceleration was understood by a simulation based on a parametric excitation of its handle movement. It was also important for this simulation to adjust initial conditions of differential equations at the start of first turn after preliminary winds. Head speed fluctuation per turn was basically determined by a principle of a parametric excitation from first turn to fourth turn, especially head speed increment was resulted from the accumulation of more positive power translated into the head through its handle and wire during delivery phase. If negative work which caused decrease of head speed was done with a little decreasing wire tensile force during single support phase of fourth turn, some reserves up to the maximum wire tensile force or handle power in actual throwing would augment release speed during delivery phase.
