WHAT IS IT?
Strength testing, in a PT sense, is not the same as maxing out in the weight room. Strength testing, professionally known as Manual Muscle Testing (MMT) is a graded technique that provides the ability for a therapist to produce an objective measurement of perceived muscle strength based on a patient's ability to resist an opposing force.
In Layman's terms, this essentially means your physical therapist is going to place a body part of yours in a specific position, and they're more than likely going to push against that same body part and ask you to resist that external force as best you can. With that numerical value, they'll be able to test continuously throughout your treatment to determine whether or not therapy is/has been beneficial for your specific injury.
SIDE NOTE: They are not going to push hard.
They're simply trying to determine whether or not you can withstand the force and maintain your position with only slight deviation, or whether or not your muscles give out due to weakness, or maybe even pain.
HOW DOES GRADING WORK?
They are going to grade you on an integer - only, numerical scale, with 5 being the best. You may hear some therapists use terminology such as 4+ or 4- and that is more of a subjective notation for your therapist to notate smaller gains or regressions in strength or ability.
SIDE NOTE: They do not share these tested scores with anyone aside from your referring specialist, as it is common lingo utilized to extend information across fields of medicine.
CAN I DO THIS AT HOME?
No.
Simply put, Manual Muscle Testing seems like a simple concept, but your physical therapists complete a 3-year doctorate program to ensure that they're testing injured areas in the correct way, while respecting protocols instilled by your orthopedic specialists, or your surgeon. It's vital that you do not attempt to test yourself, whether alone or with a partner.