Patrick Ward talks about movement reserves and physiological buffer zones. A while back, I posted about variability for stability. McGill always considers load vs capacity.
I can go on and on but ultimately it comes down to having some wiggle room to spare.
And in manual and rehabilitative therapy, it is also important to have a shed of tools (treatment options) in order to be able to match the requirements - or presentation - of the individual you are working with in the event that your first choice of options aren't appropriate.
Several weeks ago, I posted several foot-ankle exercises I had used with a young gymnast to improve foot and ankle control. Unfortunately, these specific exercises weren't appropriate for one of our soccer players so I had to think laterally - yet under the same principles - to match the exercise to the individual.
Here are the ones I used.