Hi,

Some people when starting riding a bike do pedal too slowly.

The answer is simple, tell them to pedal as fast as they feel
comfortable before changing up, and work on pedalling faster.
For hills drop gears if your pedalling is slowing down.

This will literally get you up to speed faster as it requires
less initial development of core leg strength, and that can
be worked on later at lower cadences once you can pedal.

rgds, sreten.