Body
Grasshoppers -- which can grow up to six inches long in some areas -- have extremely strong leg muscles, especially in the hind legs. The dense, fibrous muscles that make up the legs allow a one-inch grasshopper to easily leap up to 20 inches. Although grasshoppers have three sets of legs, the hind legs are by far the largest and strongest.
Wings
Let's not let the grasshopper get away with pulling a quick trick, though -- many species of grasshopper also have wings. Very often, when a grasshopper hops, it will also use the wings in conjunction with hopping, making the hop look much longer than what was actually created by the legs. The winged species contain four wings, all attached to the thorax. When not in use, the wings fold back against the body.
Making the Jump
Prior to making the jump, the grasshopper's large legs act much like a catapult; they squat and bend, placing the femurs pressing against to the other half of the leg. The compression builds tension and allows the grasshopper to take off with a velocity closing in on 10 feet per second. According to Graham Hoyle, a scientist from the University of Glasgow, this places the grasshopper's muscle power second only to the muscles that close a clam's shell.
Controlling the Ability
Like humans, the grasshopper controls its movements by firing impulses as signals. The jumping muscles contain two nerve fibers. Only one focuses on the leaping ability, while the other is a slow-action response. Outside of aggression, all impulses trigger the leaping muscle. Past this, the grasshopper can also control the distance of the hop by sending different numbers of impulses. Three signals produce the complete effort, while two and one produce only moderate to light jumps.