Manual Muscle Test (MMT)

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

“The first editions of two classic textbooks describing muscle strength testing were published in the 1940s by Daniels, Williams, and Worthingham68 and Kendall and Kendall.69”¹

“One primary difference between these texts is the focus on testing muscles as they work to move a joint in planar motion (acting as a group; Daniels et al.68) or testing muscles based on how each one individually contributes to motion (based on origin, insertion, and action; Kendall et al.69)”¹

Procedure

1. Consistency in Explanation
2. Assess unaffected side first
3. Precise patient positioning
4. Stabilization
5. Consistent hand placement

Assess Unaffected side first

The unaffected side should always be assessed first in order to have a “baseline” to compare the affected side with¹. In addition, this also helps the patient understand what is required of the affected leg, which will help reduce apprehension¹.

Precise Positioning

The patient should be positioned precisely in order to determine weaknesses between two extremities or even between sessions. In addition, the position should isolate the muscle and optimize the muscle’s ability to produce a force¹. Lastly, the position should prevent the patient from compensating and altering the movement or be obvious to the clinician when the patient is compensating¹.

• One-joint muscles (e.g., soleus, gluteus maximus, and pectoralis major) are typically assessed at the end of a joint’s range of motion.
• Two-joint muscles (e.g., biceps brachii, rectus femoris, and hamstrings) are typically assessed at the mid-range of joint motion.33,71

Stabilization

Most commonly, one of your hands will be used to help stabilize the patient while the other hand is used to provide resistive force to the muscle being tested. Providing stabilization for the patient helps to reduce substitutions and increase testing reliability and often allows the patient to feel more comfortable exerting maximal force against examiner resistance.

Consistent hand placement and force generation

Lever Arm

Lever arm: The patient’s ability to resist examiner force has a great deal to do with the length of the lever arm through which the force is applied. The patient will be able to resist force to a greater extent (sometimes much greater) when a short lever arm is used versus a long lever arm (see the Try This! exercise on the following page). Thus, it is imperative that the length of the lever arm is consistent each time the test is performed through the course of rehabilitation. Most commonly, to allow for more sensitive and discriminative grading during MMT, you should use a long lever arm.33,71

Direction of Force

“Direction of force: The placement of the hand that provides the testing force, as well as the direction(s) of the force provided, are highly important. Once the limb or body segment is in the optimal testing position, pressure is applied in a direction (or directions) that is directly opposite the line of pull of the muscle. The more precise your direction of force, the better each muscle’s primary action can be elicited. Imprecise direction of examiner-applied force can substantially diminish the accuracy of the test. For example, testing of the tibialis posterior requires the ankle joint to begin in a position of plantar flexion and inversion, with the examiner’s force applied in the directions of dorsiflexion and eversion.72 If the examiner fails to apply adequate force in the direction of dorsiflexion (primarily applying force in the direction of eversion) then the patient’s tibialis anterior would likely attempt to kick in because it is also a strong ankle invertor.”

Speed of Force production

“The resistive force you provide should ramp up over the course of 1–2 seconds, be held 3–5 seconds, and then be ramped down over the course of 1–2 seconds”

Magnitude of Force

“As mentioned in the Gross Muscle Strength section, you must provide adequate force to overcome the force produced by the patient for any given muscle. The magnitude of force will naturally be different for smaller muscles versus larger ones.57 It should be intuitive that one will not provide the same amount of force when testing the biceps as one would use to test the extensor digitorum of the hand.”

Grading

MMT Grading Scale

Letter	Number	Definition
	0	No evidence of contraction
Tr	1	Slight contraction, no motion
Poor- (P-)	2-	Movement through partial range in gravity eliminated position
Poor (P)	2	Movement through complete range in gravity eliminated position
Poor+ (P+)	2+	Movement through complete ROM in gravity eliminated and thru less than half ROM against gravity
Fair- (F-)	3-	Movement through complete ROM in gravity eliminated and thru less than half ROM against gravity
Fair (F)	3	Movement through complete test ROM against gravity
Good (G)	4	Movement through complete ROM against gravity and mod resistance
Normal (N)	5	Movement through complete test ROM against gravity with MAX resistance

Grading Scale
Manual Muscle Tests
Grades		Definition
Numerical	Terminology
Against gravity
5	Normal	Holds test position against strong pressure
4+	Good plus	Holds test position against moderate to strong pressure
4	Good	Holds test position against moderate pressure
4-	Good minus	Holds test position against slight to moderate pressure
3+	Fair plus	Holds test position against slight pressure
3	Fair	Holds test position against with no added pressure
3-	Fair minus	Gradual release from test position
2+	Poor plus	Moves through partial ROM
Horizontal plane
2+	Poor plus	Moves to completion of ROM and holds against resistance
2	Poor	Moves through complete ROM
2-	Poor minus	Moves through partial ROM
1	Trace	Tendon becomes prominent but no visible movement of the part
No movement
1	Trace	Feeble contraction felt in the muscle but no visible movement of the part
0	Zero/Absent	No contraction felt in the muscle
Data from Fruth1.

References

1.

Fruth SJ. Fundamentals of the Physical Therapy Examination: Patient Interview and Tests & Measures. 2nd ed. Jones & Bartlett Learning; 2018.