Bionics enhance human strength and endurance from the inside out. An alternative to boosting physical abilities is to wear some type of hydraulically or otherwise powered device, either armor (an enclosed metal suit with the wearer inside) or an exoskeleton, in which the human wearer is only partially enclosed. Lobsters are born with an exoskeleton serving as a protective body armor, as are crabs and crayfish.
In Robert Heinlein's Starship Trooper (1959), soldiers wear mechanized suits that give them superior strength, vision, hearing, and protection against weaponry. Bruce Sterling describes armor consisting of a wearable exoskeleton in A Good Old-Fashioned Future (1999).
In the film Aliens (1979), Ripley wears an exoskeleton -- a mechanical lifting device - to become a "temporary cyborg" in her fight with the acid-spitting alien on the loading dock of the spaceship. The human soldiers in the underground city of Zion in the Matrix wear exoskeletons equipped with machine guns in the arms to battle the sentinels -- machines that invade the city.
Now science fact is once again catching up with science fiction. Inventor Troy Hurtubise has build several versions of a personal suit of body armor designed to be strong enough to survive attack from a grizzly bear.
His latest mode, called the Mark VII, is made from stainless steel, heavy-gauge aluminum, and cast titanium. It features a built-in video screen, cooling system, pressure-bearing titanium struts, advanced protective airbags, shock absorbers, fingered hands, swivel shoulders, and built-in arms.
Yoshiyuki Sankia of the University of Tsukuba in Japan has developed a motor-driven, wearable exoskeleton called the Hybrid Assistive Limb, or HAL. By strapping HAL to the waist and legs, people with disabilities will be able to talk again. There is also an upper portion of the exoskeleton that enables the wearer to lift up to 80 pounds more than they can carry without wearing HAL.
Sensors attached to the wearer's skin detect signals sent from the brain to the muscles indicating an action to be taken, such as moving a leg. The signals are detected by the sensors, which activate the exoskeleton's motors and perform the action.