Final answer:
A nurse should prevent lift injury by keeping the back straight and using the legs to lift, which reduces the forces on the spine and prevents injuries.
Step-by-step explanation:
To prevent lift injury when transferring a client from bed to chair, a nurse should keep the back straight and use leg muscles. This is important because lifting with the back or twisting the body while lifting can cause significant strain and result in injury. When the back is kept straight and the legs are used to raise the body and load, the forces exerted on the spine are substantially reduced, preventing injuries.