Difference between S.A.I.D. principle & specificity principle?

[SmithJLee]

I'm a former certified trainer but—until this year—I had been out of the fitness game and out-of-shape for over a decade (due to several non-gym related injuries). I have the short-term goal of getting back in shape and getting recertified and this morning, during my daily walk, I was trying to remember the difference between specificity and S.A.I.D.

Yes, of course, I could Google it, but if someone here could explain it in a way that enabled her or him to remember it, that would be helpful.

Also, I had been ISSA certified but I want to go NASM or ACSM this time around.

[KyleAaron]

Specificity principle is about movement skills, SAID about general physical traits.

Saying, "squats make you better at squatting" is specificity. Saying, "squats make you stronger" is the SAID principle.

The key is the "imposed demand" part. Simply doing squats, like throwing hoops or practicing darts, won't improve the strength of anyone but the most detrained person. Adding sets, reps or load, or some similar variable, will impose a demand on the system which it adapts to.

Put another way, there's that stress-recovery-adaptation cycle. In learning skills, you need only time for recovery; in adapting to imposed demand, you need time, but also rest and food.

Obviously, there is overlap. It's not really possible to impose a demand on the system without doing some particular movement, and doing that particular movement improves your skill in doing that particular movement. Likewise, repetitively practising some movement will lead to some development of the muscles etc involved in that movement.

Quibbling between the two isn't a useful distinction for the people we train. Personal trainers don't work with athletes, coaches do. We'll be working with people who are 50% or less of world record performance. For them, developing a movement skill will make them stronger, and making them stronger will improve their movement skill.