... photographer Edweard Muybridge continued his studies underwritten by the University of Pennsylvania. He did studies on the motion of animals and of humans, mainly for artistic purposes rather than scientific ones. He would often use young women in various stages of undress for these experiments.
One of Muybridge's models was himself, as he is shown here, naked swinging a pick axe. Muybridge always considered himself trim and athletic, even when in old age, and he was close to that here, at age 51. Why a pick axe? Muybridge liked to think of himself as somebody who helped tame the wild west, and perhaps to him a pick axe was a sign of that wild west.
Although Muybridge was supposedly studying motion, he often photographed his female models doing things that "nice" women did not do at the time - such as smoking. It is hard to figure out what can be learned of motion by photographing women smoking.