RowToTri wrote:
Sorry to keep replying to you! I want to do a little thought experiment about power (or not) to keep a bike and rider stationary in a 30 mph wind: Without a force applied, the bike will roll backwards. If the force is applied by a rigid structure and nothing is moving in order to generate the force, then yes, power is 0. But if it is held in place by a human applying force to the pedals, power is definitely required, even though the bike's power meter would read 0 because cadence is 0. Things are moving - your heart is pumping, electrons are flowing through neurons, muscle fibers are contracting...
Think about it as if it were an electric motor, rather than a human, connected to the crank. Just enough current is supplied to the motor to keep it from turning backwards. The power in that case is easy to measure - voltage * current.
Comment? Disagree? Agree?
Force is being applied to the pedal, but since it isn't moving, then by definition no power is being "used"...but, in the case of a muscle supplying that force, electro-chemical energy will be "spent"...but, as you say, a rigid link could also easily do the same job.
http://bikeblather.blogspot.com/