Ergonomics of US

Around ¾ of ambulance assistants are females, whose hands are smaller than those of males’. The average length of a female hand is 172mm (189mm), with a width of 74mm (84mm). For all assistants to grab the handle (possibly with the actuators) tightly during turbulence, the surface area of width and length of the handle should be limited below 342mm sqr.

The assistants are required to apply at least 3.8, 4.2, 6.4 Newtons of forces in the x,y and z direction during a FAST examination with somehow an awkward gesture. In long terms, this will fatigue mainly the shoulder joint of the assistant as well as the wrist. This effect can start appealing 5 years into the career.