Some of the tools, such as back-and-forth print correspondence, are older but still valuable.
Jump again almost immediately after your feet make contact with the ground and return to the starting position, and repeat for a continuous, back-and-forth hopping.
The current version allows the cable to swivel, which allows for a smooth back-and-forth motion.
The back-and-forth motion also engages your legs and your core.
Long, it is easy to obtain the equivalent of a slowly-moving very long pendulum which is too sluggish to follow the back-and-forth movements of its supports.
Although by compounding corresponding portions of the diagrams given by instruments of this type, it is possible to determine the range and direction of the movement of which they are the resolved parts, their chief value is that they enable us to measure with ease the extent of any vibration, half of which is called its amplitude, and the time taken to make any complete back-and-forth movement, or its period.