The purpose of this study was to quantify the hammer head speed generating mechanisms of male hammer throwers, using a simplified model for the thrower and hammer. Fourteen male hammer throwers of differing skill level performed maximum effort throws in an indoor experimental facility. The dynamic contributions to the generation of hammer head centre of gravity speed from (1) joint moments, (2) gravity, (3) a generalised initial velocity term, and (4) an acceleration constraint term relating to the proximal end of the simplified system were derived from the equations of motion for the individual segments and constraint conditions arising from the connection of adjacent segments. The motion-dependent term (MDT), a nonlinear term consisting of centrifugal force, Coriolis force and gyroscopic effect moment components, was the greatest contributor to hammer head speed, with the centrifugal force component especially important. The components of the MDT would be key factors in differentiating between throwers of different skill level.