How does a bicycle trainer work?
A bicycle trainer is a bicycle frame fixed to an immoveable
frame fastened to the floor, or a bicycle that runs on horizontal
rollers, on which a person can pedal as an indoor exercise. The
pedalling pressure can be adjusted, and the distance pedalled, time
taken, heart beat, etc, can be recorded. Racing cyclists often warm
up on a bicycle trainer before a race, and then warm down after the
race - so as to avoid straining their muscles.