Kenetic Energy Storage (KES) Is how you store motion into a flywheel or electrical charge system (See below), for later usage.
https://www.youtube.com/watch?v=GchjFXif_hYObviously it's a bit more difficult to use a flywheel on a bicycle, but a trike on the other hand is very doable.
For those who want to understand KES more in depth.
https://en.m.wikipedia.org/wiki/Flywheel_energy_storagehttps://www.treehugger.com/bikes/amp/engineering-student-builds-flywheel-energy-recovery-into-bike.html 