Passage Summary: Special shoes don't actually make your leg muscles work any harder than regular shoes do, yet people who wear them still end up with stronger legs.

Reasoning: N/A

Analysis: The paradox here is the disconnect between the 'effort per step' and the 'result over time.' If the shoes don't provide more exercise per step, how are people getting stronger? To resolve this, we need a third factor that explains the improvement. Perhaps the shoes are so comfortable that people walk ten miles instead of two, or perhaps the 'fitness enthusiasts' who buy them are also hitting the gym more often. It’s a bit like buying a fancy new blender and suddenly getting healthier—it’s probably the kale you're finally buying, not the motor in the machine.