Equating, conflating, exaggerating, whatever you want to call it, it's easy to imagine all those pedal strokes make one a cheetah-swift runner. Ballerina like in grace and rhinoceros like in power. The reality is the most ridiculous pain through feet legs back and lungs and giving up heinously close to home.
BONUS TIP: Do not be tempted by triathlon. Would you set out to make a bloody Mary if you only had tomato juice? Make a BLT with just lettuce? Buy neapolitan ice cream that was all strawberry? Consume a breakfast cereal that just snapped?