The Body in Motion concerns the integration of film in experimental physiology in the late nineteenth and early twentieth centuries. Descriptions of motion studies of beating hearts and the human gait are given as evidence that cinematography quickly became an experimental technique with broad visual appeal.  With instruments such as the X-ray, myograph, the kymograph, and the electrocardiograph; Doctors have been better able to diagnose disease, breaks, fractures and ailments.

Cartwright reads into these early graphs and films a particular way of conceiving, studying, and depicting life distantly, graphically, and sometimes violently: The Body in Motion, and/or how the body should act in motion.