Below are the different MMT grades. Short video clips are included near the end of this post discussing about manual muscle test grading.
How to Grade Muscle Strength Through Manual Muscle Testing - Manual Muscle Test Grades
Grade 5 (Normal; 100%)
The patient or subject can complete the whole range of motion (movement) against gravity with maximum resistance applied by the therapist at end-of-range.
Grade 4 (Good;75%)
The subject can complete the whole range of motion against gravity with moderate resistance applied by the physical therapist (PT) at end-range. Testing the uninvolved limb should always be considered to know whether you are applying too much force on the involved limb or not.
Grade 3+ (Fair+)
The patient can complete the motion against gravity with minimal resistance applied by the examiner at end-range.
Grade 3 (Fair;50%)
The patient can only complete the range of motion against gravity. When external (outside) force is applied by the PT, the patient gives way.
Example: Let's say, you're going to test the muscle strength of your patient's/client's left knee extensors (quadriceps femoris/quads). Your patient is sitting on the edge of a bed or treatment table with his or her legs dangling. Tell your client to straighten his or her left knee. If your client can perform the movement fully, then you'll know that the grade is at least 3. But, he or she gives way immediately upon applying force.
Grade 2+ (Poor +)
In grade 2+, your subject can move his or her joint at a certain range but cannot complete the motion against gravity. When gravity is eliminated, such as performing the motion in side-lying, your client can perform the movement at full range of motion with ease. However, muscles being tested give way immediately when you apply some resistance.
Grade 2 (Poor;25%)
Your patient cannot perform the movement against gravity. But patient can do complete range of motion when pull of gravity is eliminated. No resistance is applied.
Grade 2 - (Poor -)
Initiation of movement can be done only as gravity is eliminated. That is, only a partial movement is observed. Here, full range cannot be completed.
Grade 1 (Trace)
Patient is not able to move the joint even with gravity eliminated. However, closer examination by the therapist would reveal slight muscle contraction through palpation.
Grade 0 (Zero; No trace)
No contraction is noticed, even with physical therapist's palpation (touch).
Note: Always tell your client about what procedure you are going to perform and what you are going to obtain from that procedure. Remember to check the uninvolved side first and be consistent on where you apply the resistance. Also, instruct your client not to hold his or her breath as you apply force or resistance. For more information check out the Do's and Don'ts in Manual Muscle Testing.
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Manual Muscle Testing Videos
The following are some videos (thanks to Youtube and the uploader) on manual muscle testing grading. The first video is a brief explanation of how to easily know if a muscle being tested is at least grade 3. The second video demonstrates how to determine the other grades.
A Brief Explanation on MMT
You can view more manual muscle testing procedures at Chad's Youtube channel through the URL below. Thanks.
Video Source: http://www.youtube.com/user/chadcurtisschneider
Practice, Practice, Practice Correctly
Often, MMT grading is subjective, relying on the physical therapist's judgement. At first, you may have difficulty deciding on what grade your going to give a particular muscle or muscle group, especially grades lower than 3. Correct practice is the key to a reliable manual muscle testing.
Mastering muscle testing may be a daunting task for the physical therapy student. Imagine those many muscles to test. But, as you go into your clinical internship, muscle testing becomes easier for you.
A good companion book for learning manual muscle testing is the "Daniels and Worthingham's Muscle Testing: Techniques of Manual Examination, 8e." The book has a good companion DVD where over 100 muscle tests and procedures video clips are included to enhance your learning and manual muscle testing skills.
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More physical therapy MMT books and muscle testing devices at our PT Notes Associates Store
Hislop, H. & Montgomery, J.: Daniels and Worthingham's Muscle Testing: Techniques of Manual Examination. 6th ed. W.B. Saunders Company, 1995.