Everything about the pike's shape serves one movement. The body is a straight cylinder, the dorsal and anal fins are placed close to the tail so that the whole rear third acts as a single paddle, and the mottled green flank breaks up outline against weed. The fish holds motionless, then covers a body length or more in a fraction of a second.
High-speed analysis of pike fast-starts shows a C-shaped body bend followed by a single sweep of the tail. Mechanical power calculated from those films reaches several hundred watts per kilogram of muscle fibre, close to the maximum measured for vertebrate striated muscle, which led researchers to conclude that muscle power itself sets the limit on the strike rather than any stored spring. Backward-curved teeth then prevent escape once the jaws close.
Elastic energy storage does occur in fish backbones during steady swimming, but at the high strain rates of an escape or a strike most of that energy is thought to be dissipated rather than returned, and how much it contributes to a pike's lunge has not been measured directly.