Why can a person cycle more in a day than they can walk or run?

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A.T. said:
But walking and running also involves lifting the center of mass, even on level ground.
Very little raising and lowering is necessary with the right technique but that technique can be very tiring. russian dance (wait for the ads)
 
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sophiecentaur said:
Very little raising and lowering is necessary with the right technique but that technique can be very tiring. russian dance (wait for the ads)
Yes, the straight leg acting as an inverted pendulum raises the CoM in normal walking, but is still more efficient than bending the leg to keep the CoM on constant height, because then muscles need more force to stabilize the bent joints.
 
A.T. said:
Yes, the straight leg acting as an inverted pendulum raises the CoM in normal walking, but is still more efficient than bending the leg to keep the CoM on constant height, because then muscles need more force to stabilize the bent joints.
The muscles 'waste' a lot of energy, just holding a load up and doing no actual work on the load. Fibres keep tensing up and relaxing, which uses significant energy just to stay still. A Bike frame uses no energy just staying rigid and the rider is sitting there, doing no work apart from pedalling etc. when necessary. Far more efficient.
There is a certain amount of energy storage in the leg tendons (same for horses too) which gets returned to the system but that's not as good as you get from a wheel.