It used to be that the hammer was as heavy as the user desires. Then, with the introduction of mass manufacturing, hammers become available only in discrete weights and the user was forced to make due with a hammer that is either slightly too heavy or slightly too light, because nobody manufactures the precise weight of hammer the user desires and the local industry to have a custom hammer created for yourself no longer exists.
My meaning was that the fundamentals for the task cannot be avoided. Nature doesn't shape itself for our convenience unbidden. You can change your approach and the ergonomics but there is no helping that digging a trench is going to involve moving a lot of heavy dirt.
