Most paint sprayers are designed with the reservoir located in front of the handle. This provides an obvious ergonomic problem. Enter industrial design consultancy Bluemap:
"Campbell Hausfeld, a leader in hardware and power painting tools manufacturer, wanted to establish a unique design for a handheld airless paint sprayer in the marketplace. Bluemap Design's product development team uses extensive user testing, motion study, and observation during the research phase. We found that all handheld paint guns have a cantilevered structure, which leads to a lack of balance and wrist and forearm fatigue while painting."
"To counteract this tendency, we designed the sprayer with an overall vertical structure, with the handle between the motor at the top and the paint reservoir at the bottom. The result was an ergonomically conscious product that differentiated the Campbell Hausfeld Airless Sprayer from its competitors regarding look, feel, and comfort."