Solved by a verified expert:Assume that the amplitude of the EMG has a greater change from rest when the same weight is lifted overhand rather than underhand (the typical outcome in this experiment). The muscles that are doing the lifting have to produce the same force to lift the same object. So why is the change in EMG amplitude greater when the lifting is overhand rather than underhand? Before answering this question, you may wish to assess the muscle mass at different places in your forearm