Pogo stick
Overview
 
A pogo stick is a device for jumping off the ground in a standing position with the aid of a spring, used as a toy or exercise equipment. It consists of a pole with a handle at the top and footrests near the bottom, and a spring located somewhere along the pole. The spring joins two sections of the pole, which extends below the footpads.

The operator places his feet on the footpads while balancing on the pole, then jumps up or down with a bending action of the knees to add or subtract energy in the spring.
 
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