I am all about "being strong." And I usually say that means being able to receive large amounts of resistance without faltering.
But if you frame strength in a temporal context, pretty interesting things happen. I mean, it makes sense that while someone might squat 300 lbs 1 time, that same person would only be able to hold a 1-min squat with much less weight. What weight could they hold for 7 days? A month? 3 years?
Of course, the resistance involved on that sort of time-scale would be too much to handle if we were actually squatting. But imagine a similar "exercise" going on internally, that is really just each of us "receiving resistance" from the world around us. What if we could get stronger at that exercise? What might we fix? And how would we not get injured?