Abstract: The invention relates to a weights system, for use with a bar, including a body, a weight means to give the weight system a useful weight for performing exercise and a lock and release mechanism. The lock and release mechanism is movable between a locked state, whereby the body and weight means are retained on the bar, and a released state which is operable to release the body and weight means from the bar. In use, the lock and release mechanism enables quick and easy exchanging, removal or addition of weight to the bar for use in a sequence of exercises. The invention also relates to use of the weights system with a blade. The invention also relates to a method of use of the weights system. The invention also relates to a method of use of the weights system and blade apparatus.