Because of the terrain outdoors, like rolling hills, “it’s really hard to [work on your cadence] out in the field because you’re varying your speed and your cadence, probably,” says Kernozek.

In the fire and emergency services, hard work is more than a job requirement—it’s a way of life. The profession demands physical strength, mental acuity, emotional resilience, and integrity.

If so, then how come people, and even animals, often prize things that require hard work for no additional payoff? Why is being hard-to-get a route to value? Anyone who has labored hard for ...