Sand Castles: A mental model of endurance training
Training endurance is like building a sand castle. You need sand and water, the sense not to overdo it, and the expertise to make something great.
- Basic endurance is like piling dry sand. It can’t be shaped, just piled higher. For every inch of height, it takes a greater volume of dry sand than the inch before.
- Adding intensity is like adding water. You can increase the angle of repose of the sand, steepening the cone, getting higher with the same volume.
- Artists (great coaches) can get the saturation just right, creating amazing sculptures. But those sculptures will always be temporary.
- HIIT proponents misunderstand the sand/water relationship. They assume that water is the big secret:
- “If water makes sand piles steeper, let’s just use that!”; and
- “If the pile of wet sand starts to crumble, add more water!”
- The distinctions are:
- First, it’s not either sand or water, but the mix of sand and water that’s important;
- Second, wet sand is born from dry sand; it’s not independent. The volume of dry sand still determines the ultimate height of the cone or size of the castle; and
- Third, if the pile starts to ooze downward, adding more water won’t help. To restore it, you have to dry it out (by adding more dry sand).