Abstract: An inertial weight for physical conditioning includes a hollow housing having an inner cavity with first and second spaced apart opposed ends and defining a longitudinal axis extending therebetween. The inner cavity tapers transversely outwardly along the longitudinal axis from a mid section to each of the first and second spaced apart opposed ends. A viscous fluid mass is carried in the inner cavity, the viscous mass filling the inner cavity less than full to allow the viscous mass to move within the inner cavity. An attachment member is affixed to at last one of the opposed ends.