An inch

There is a point where something is weak, then it becomes strong, only to become weak again. Like a 'bell curve'... The human lifespan is like this: a baby, to adulthood, to decrepitude and death.

Seek to do only what is necessary to find that optimal point of strength. Sometimes it requires just an inch of movement.

Just enough?

It is so tempting to stretch, to extend, to reach. To force, to push.

Don't do this. Just do what you need to do to accomplish the result and nothing more.

Aim for this ratio: minimal effort achieves maximum results.

A different way?

Tai chi advocates moderation in all things. e.g. over-training is as bad as under-training. If you do not train enough, there will be very little fitness benefit and no martial development.

If you train too much, the body will become tired and there is an increased risk of injury.